Passive House Plus (Sustainable building) issue 35 IRL by Passive House Plus (Sustainable Building)

INSULATION | AIRTIGHTNESS | BUILDING SCIENCE | VENTILATION | GREEN MATERIALS

S U S TA I N A B L E B U I L D I N G

ZERO IN

Inspired Sandycove home offers route to net zero energy living

SPECULATIVE EFFORT

Radon reductions

Study shows lower lung cancer risk in passive houses

Deep retrofit

Exclusive: details of government scheme emerge

Pecking order

Award-winning passive house inspired by chicken sheds

Issue 35 €6.95 IRISH EDITION

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ADVERTORIAL

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PA S S I V E H O U S E +

Publishers

Temple Media Ltd PO Box 9688, Blackrock, Co. Dublin, Ireland t +353 (0)1 210 7513 | t +353 (0)1 210 7512 e info@passivehouseplus.ie www.passivehouseplus.ie

Editor

Jeff Colley jeff@passivehouseplus.ie

Deputy Editor

Lenny Antonelli lenny@passivehouseplus.ie

Reporter

John Hearne john@passivehouseplus.ie

Reporter

Kate de Selincourt kate@passivehouseplus.ie

Reporter

John Cradden cradden@passivehouseplus.ie

Reader Reponse / IT

Dudley Colley dudley@passivehouseplus.ie

Accounts

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Design

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EDITOR’S LETTER

editor’s letter W

e have been living through extraordinary times, and the next few months are set to be no different. When I sit down to write the editor’s letter for our next issue, the next US presidential election will have taken place, hopefully leading to a peaceful, democratic, conclusion culminating in the end of the reign of a man who has done so much damage to the world in such a short time. We will be closer to a conclusion on the Brexit saga, hopefully delivered in a way which doesn’t threaten the peace, stability and prosperity of Ireland and the UK. We will also be heading decisively into winter, and I hope with every fibre in my being that a time of year when people tend to stay indoors, close windows and reduce ventilation doesn’t contribute to a significant spike in Covid-19 cases. If the authorities had been quicker to accept the growing weight of evidence on the airborne path as not only a significant but perhaps the most significant route for transmission of Covid, we could have been so much better prepared, and our chances of avoiding a dreadful winter may have been substantially better. That’s not to say that airborne spread is the only issue, or that accepting its significance would lead to its eradication. We’re faced with a fiendishly complex problem, and solving it requires us to make lots of changes in how we live in our day to day lives. So, ventilation is important, but if we place too much emphasis on it, it could give us false

ISSUE 35 confidence. That includes everything from social distancing, to spending less time mixing with people from outside our households, to wearing masks, to being hypersensitive to activities that may significantly increase aerosols, and many more considerations besides. But caveats like this side, it’s becoming increasingly clear that ventilation is a critical tool that we must use to tackle Covid, and with much higher ventilation rates than we would normally advocate in buildings where people are congregating. Hopefully in the process we’ll start to collectively gain an appreciation of the health, wellbeing and productivity benefits that good ventilation brings. In the longer term, this should give us pause to reflect on how to ensure our new build and retrofit efforts help to give us resilience in a world where pandemics may linger on, or where another pandemic may be around the corner. It’s one thing to justify colder indoor temperatures and higher heat energy use over this winter given the exceptional circumstances we face. But neither our pockets nor the planet can afford this to become part of the new normal. We must learn from these circumstances and prepare ourselves so that our buildings don’t threaten our health, but instead protect it, and help us to adapt to whatever adverse circumstances the future may throw at us. Regards, The editor

Contributors

Simon Bell Passive House Association of Ireland Toby Cambray Greengauge Building Energy Consultants Marion Jammet Irish Green Building Council Marc Ó Riain doctor of architecture Peter Rickaby energy & sustainability consultant David W Smith journalist

GPS Colour Graphics www.gpscolour.co.uk | +44 (0) 28 9070 2020

Cover

Mel Reynolds’s mews passive house Photo by Paul Tierney Publisher’s circulation statement: 9,000 copies of Passive House Plus (Irish edition) are printed and distributed to the leading figures involved in sustainable building in Ireland including architects; consulting; m&e and building services engineers; developers; builders; energy auditors; renewable energy companies; environmental consultants; county, city and town councillors; key local authority personnel; and to newsagents nationwide via Easons. Disclaimer: The opinions expressed in Passive House Plus are those of the authors and do not necessarily reflect the views of the publishers.

ABC Certified Average Net Circulation of 6,417 for the period 01/07/18 to 30/06/19

About

Passive House Plus is an official partner magazine of the International Passive House Association. Passive House Plus (Irish edition) is an official magazine of the Passive House Association of Ireland.

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CONTENTS

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CONTENTS COVER STORY

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INTERNATIONAL

NEWS

COMMENT

This issue features an intriguing new passive house apartment building in north-west Spain.

Government retrofit plans revealed, Dún Laoghaire to get one of world’s largest passive house schemes, and Irish courts make landmark ruling on radon.

Returning to his regular series on the evolution of sustainable building during the 20th century, Dr Marc Ó Riain takes look at the first serious attempt to build a house with net zero energy use; and Dr Peter Rickaby writes about domestic retrofit in the wake of Covid, and the importance of doing it right.

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CASE STUDIES

Highland warrior Scottish passive house built with innovative local timber system

A beautifully detailed and rustic new passive house in the north of Scotland was built with a unique offsite construction system using local timber, and was created by a design-and-build firm that aims to put sustainability at the heart of everything it does.

Pecking order Award-winning passive house makes an elegant mark on the South Downs

Despite the challenges of getting planning permission within a national park, a new passive house on a hillside in the South Downs managed to woo the planners with a sympathetic, discerning design inspired by a surprising source — two dilapidated old chicken sheds.

INSIGHT Radon

Speculative effort Extraordinary A1 Cork upgrade is Ireland’s first developer led Enerphit

In 2016, builder David Lane decided to buy a large 1950s house in Cork city and undertake a tricky deep retrofit, turning the run-down property into an upmarket passive house. It’s about as far from the traditional model of property development as you can imagine — but it holds some crucial lessons for what we do with our urban buildings in the era of climate breakdown.

Zero in Inspired design offers route to net zero energy living

It sounds like an impossibility: a high density, architectural, zero energy home on the tightest of back garden sites, adaptable to the needs of everyone from empty nesters to a family of six without opening a toolbox. But sometimes a project comes along that redefines what is possible.

CONTENTS

Radon is one of the most dangerous indoor air pollutants, yet there is little research on how it is affected by different forms of construction and ventilation. A new study, however, suggests that homes built to the passive house standard are significantly less at risk of radon build-up.

MARKETPLACE Keep up with the latest developments from some of the leading companies in sustainable building, including new product innovations, project updates and more.

The condensation myth

Condensation within the structure of buildings is a lot more complex than condensation in a sweaty pub on a Friday night, writes building physics expert Toby Cambray.

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INTERNATIONAL PAS S I V E & EC O B UIL D S F R OM A R OU ND THE WO R L D

IN BRIEF Building: Seven-storey apartment block Location: Vigo, Galicia Building method: Externally insulated clay block with concrete frame Standard: Passive house classic certified

I N T E R N AT I O N A L

S PA I N

VIGO, GALICIA, SPAIN

Photos: Carlos Prieto

striking new block of passive house apartments has risen in the city of Vigo, in north-west Spain, on the site of a popular old hotel. But the team behind the project, led by architect Leonardo Llamas Álvarez of Edifico Arquitectura, faced a daunting challenge: preserving the concrete slabs and columns from the original Hotel Galicia while building an airtight and superinsulated structure on the narrow urban site, between two existing party walls. The new walls were built from clay blocks, insulated externally with mineral wool, with new triple glazed passive house certified windows installed too. A gypsum plaster coat on the inside of the new walls provides the primary layer of airtightness. Where it faces the street, the building has a ventilated façade finished with granite, and an external lattice of pine slats for shading. The finished building has one large apartment per floor. Inside, the feel of the building is defined by the wood and concrete finishes, particularly in the circulation spaces. Cross-laminated timber from Norway spruce was used for the construction of the entrance stairs, including a first step which appears to be floating in thin air. Meanwhile four air source heat pumps supply an underfloor heating and cooling system in each apartment. And while the project’s developer was initially afraid that building to the passive house standard might compromise the aesthetics of the project, he is reportedly delighted with the end result — particularly with the indoor air quality. The building’s mechanical ventilation with heat recovery systems also helps to reduce the build-up of radon gas, for which Vigo is in a highrisk area. Overall, achieving the full passive house standard while preserving some of the original hotel’s structure represents a remarkable achievement on such a difficult site.

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WANT TO KNOW MORE? The digital version of this magazine includes access to exclusive galleries of architectural drawings. The digital magazine is available to subscribers on www.passive.ie

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NEWS

PA S S I V E H O U S E +

NEWS New retrofit plans to ensure no more ‘downtime’ for industry

he government is building cross-party retrofit commitments to ensure a long-term and continuous programme of retrofit work, Passive House Plus has learned. “Sources from government are working really hard and have absolute commitments from across the political landscape to ensure the retrofit industry never has a downtime again,” a source from within government told Passive House Plus. Delivering high quality deep retrofits requires investment in technical skills and expertise, and there has been concern in the industry about the stop-start and seasonal nature of grant schemes to date, and uncertainty over whether future governments will maintain current retrofit commitments. The government is also planning to ramp up retrofit activity to deliver 33,000 B2 retrofits in 2022, then 56,000 a year by 2024, the Department of Communications, Climate Action and Environment confirmed — a significant and ambitious increase on current activity. Passive House Plus has published the full statement from the department on page 20 for our readers. The programme for government aims to retrofit 500,000 homes to a BER of B2, and to install 400,000 heat pumps in existing buildings, over the next ten years. The statement revealed the government has also established a cross-departmental retrofit taskforce to develop a new retrofit delivery programme, and that SEAI is expected to announce the first details of new and expanded retrofit schemes shortly. SEAI received a €100 million funding boost in the government’s July stimulus programme. “This money will be focused on community retrofit schemes, retrofit schemes supporting those in energy poverty as well as other initiatives to support the achievement of our retrofit targets,” the statement read. Meanwhile, the Department of Housing told Passive House Plus that “The number of local authority dwellings to be retrofitted to a B2 each year between now and 2030 is currently under review and will be considered as part of the estimates process for Budget 2021”. •

No delay on ventilation changes: Department of Housing The Department of Housing expects sufficient numbers of people will have undergone training to satisfy requirements for new ventilation systems introduced to the building regulations last November. Technical Guidance Document F requires that ventilation systems are designed, installed and commissioned by competent people, and that each system’s performance is independently validated. The relevant training courses are run by Waterford and Wexford Education and Training Board, which had been unable to complete courses until recently due to Covid-19 restrictions. A departmental spokesperson told Passive House Plus: “DHPLG are working closely with Waterford Wexford Education and Training Board and with NSAI to train installers and validators and it is expected sufficient validators and installers will be in place for full implementation of Part F 2019.”

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Experts call for CO2 sensors as tool in Covid fight

O2 levels in rooms and other enclosed spaces should be used as a proxy for Covid transmission risk, a number of leading experts have said, as the evidence increasingly points towards airborne transmission being a major factor in the spread of the virus. “Since the coronavirus is spread through the air, higher CO2 levels in a room likely mean there is a higher chance of transmission if an infected person is inside,” leading aerosol scientist Prof Shelly Miller writes in The Conversation. “Simply put, the more fresh, outside air inside a building, the better. Bringing in this air dilutes any contaminant in a building, whether a virus or a something else, and reduces the exposure of anyone inside.” Miller cites a 2019 study on a tuberculosis outbreak in Taipei University, Taiwan, where many rooms were poorly ventilated and reached CO2 levels above 3,000 parts per million (ppm). When engineers brought levels down to under 600 ppm the outbreak stopped. “According to the research, the increase in ventilation was responsible for 97% of the decrease in transmission,” said Miller, before going on to recommend a CO2 target of 600 ppm. Meanwhile REHVA, the Federation of European Heating, Ventilation and Air Conditioning Associations has called for the installation in school classrooms of CO2 monitors with traffic-light indicators, “at least in schools where ventilation depends on opening windows and / or grids”. Prof John Wenger, director of the Centre for Research into Atmospheric Chemistry in UCC suggests a target of 1,000 ppm if CO2 is being used as a proxy for Covid in classrooms, and argues that room level transmission is “the key. It’s in the air, and it can fill a room. The amount of the virus in the air can accumulate, and we get an increased exposure. If you’re indoors, in a poorly ventilated room for a long time, then you’re at quite a high risk even if you’re distanced, because the air moves around.” A new study by leading aerosol scientists Zhe Peng and Jose L Jimenez, titled ‘Exhaled CO2 as Covid-19 risk proxy for different indoor environments and activities’, has found that indoor CO2 measurements by low-cost sensors hold promise for mass monitoring of indoor aerosol transmission risk for Covid-19 and other respiratory diseases, but that different CO2 level targets should be set based on the environment and activity type. The study – published as a pre-print in September – explains that target CO2 levels for a given infection risk level can vary by a factor of 100 or more depending on the situation and activity type. This is because the risk is subject to factors such as the number of infected people in a region, and the fact certain measures such as mask wearing or air filtration may reduce presence of the airborne virus without reducing CO2 levels. As Jimenez points out, certain activities increase virus emission far more than CO2 levels, such as talking, singing and shouting. “The stronger vocalization, the higher risk, and the more intense activity, the higher risk,” the study says. Jimenez nonetheless argues that using CO2 levels to monitor infection risk is a “very good idea”, because infected people exhale CO2 and Covid as they breathe, talk etc., and as both CO2 and the virus are removed by ventilation with outdoor air. •

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NEWS

Dún Laoghaire passive house scheme will be one of world’s largest

BK Architects has received planning permission for 597 homes at Shanganagh, Co Dublin, the overwhelming majority of which will be passive houses. The project has been developed in partnership with Dún Laoghaire-Rathdown County Council and the Land Development Agency. The project is currently Ireland’s largest social and affordable scheme to receive planning. Set within a historic landscape adjacent to Shanganagh Park, the proposal is centred around a new public square and an avenue leading to Shanganagh Castle. The project will be one of the largest in Europe to be designed to passive house standards, with eight buildings incorporating 546 apartments being designed to achieve passive house certification. An emphasis has been placed on pedestrian and cycle accessibility too, with the development also in close proximity to the proposed new Dart station at Woodbrook and BusConnects. One-third of the units will be social housing while two-thirds will be so-called affordable homes for rent or purchase. The development will offer a mix of accommodation suitable for larger and smaller families, couples and single people. Construction is expected to start on the site in the first half of 2021, subject to the final decision of the council, and government approval. “We are delighted to announce that Shanganagh Castle has received planning permission from An Bord Pleanala,” read a statement from passive house consultants on the project, MosArt. “At Shanganagh, 546 of the 597 new homes will be delivered to the passive house standard, representing what looks set to be the largest

passive house urban settlement in the world. The project will deliver superb energy efficiency as well as high comfort and excellent indoor air quality, and all based on a quality assured science-based design and delivery process that avoids performance gaps.” “MosArt are delighted to be the passive house consultants for this ground-breaking scheme, providing energy consulting services, including BERs, thermal modelling and passive house modelling, together with development of ventilation and airtightness strategies. “We look forward to playing our part in the delivery of the scheme, which will provide much needed high-quality affordable housing for our citizens.” Meanwhile Dún Laoghaire-Rathdown County Council chairperson and Green Party representative Una Power said: “The achievement of full planning permission for our project in Shanganagh is excellent news for people looking to buy or rent a home in our county at an affordable cost and will make a significant contribution to meeting the council’s social housing requirements. “The development will offer people an attractive place to live that is close to key transport links and supported by a wide range of local amenities. It will also serve as a flagship for sustainable development – with best in class environmental practice incorporated into the project from the outset.” • (above) Illustrations of the proposed Shanganagh Castle scheme, which is set to become one of the largest passive house schemes in the world.

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NEWS

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Landmark case may empower tenants on radon

Photo: AlphaRadon

landmark legal case may give tenants the chance to discover if their building poses a lung cancer risk, Passive House Plus can exclusively reveal. The commissioner for environmental information has taken back a decision which denied a tenant access to test results from nearby buildings for radon, a naturally occurring radioactive gas linked to roughly 300 lung cancer cases per year in Ireland. The decision could have far reaching consequences regarding access to information on natural emissions into the environment in Ireland and across Europe. Friends of the Irish Environment member Anna Conlan submitted an Access to Information on the Environment (AIE) request in January to the Environmental Protection Agency, the state agency responsible for radiological protection, to ask if a radon test had been conducted on a property in Dublin City she was renting, or failing that from the ten most closely located homes that had been tested. The EPA told Conlan that no test had been conducted on the property, and refused the request on nearby homes on the basis that the information was personal data. Conlan appealed to the commissioner for environmental information, who upheld the EPA’s refusal decision, again on the basis that it was personal data. Conlan then instructed FP Logue Solicitors to issue a high court appeal. In September, having heard Logue’s legal argument, the commissioner conceded the case, which has to be formally struck out and sent back in October, with the commissioner required to make a new decision. “If the information relates to emissions into

16 | passivehouseplus.ie | issue 35

the environment it has to be released, except for very specific circumstances,” Fred Logue, Conlan’s solicitor, told Passive House Plus. “The directive says you can’t rely on a personal data exemption to refuse information on access to information on emissions into the environment. Radon relates to emissions that are particularly harmful. I’d be hoping that the information is released.” Logue said that the issue of personal data and emissions has long needed to be worked out. While there is established case law that access should be given to information on man-made emissions such as those occurring from pesticides, there has not been much on natural emissions, and the ones that effect homes. The office of the commissioner for environmental information told Passive House Plus it had agreed to take back the decision. “Once remitted, the case will be reviewed and the commissioner will make a new decision. As the case is ongoing we cannot comment further at this stage.” A spokesperson for Friends of the Irish Environment (FIE) told Passive House Plus: “The Access to Information on the Environment regulations are specifically intended to ensure environmental information is available in order to protect human health and the environment. The fact that it seems the commissioner is now likely to make available the information on radon concentrations means that effect may be given to the Access to Information on the Environment regulations in a way that should lead to a reduction in lung cancer deaths in Ireland. “We hope that the information will be

actively disseminated in accordance with Ireland’s obligations under article 5(1) of the Aarhuus Convention,” the spokesperson continued. “There’s a very low level of radon testing in general. There’s next to zero testing of rented properties.” While giving people access to radon levels from nearby properties may help to draw attention to how high or low levels may tend to be in a given area, it’s important that people don’t read too much into these results, as high radon levels can be registered in supposedly low radon areas for a simple reason: the ground is not homogenous, and consequently radon levels can vary greatly in adjacent buildings. Given that radon tests can be completed for less than €50, the onus should instead be on widespread testing. “In order to reduce exposure to radon far more testing needs to be done,” said the FIE spokesperson. “An awareness of radon levels in neighbouring properties would encourage this. We absolutely believe landlords need to be placed under a legal obligation to test their properties.” FIE are hopeful that the commissioner on environmental information’s decision will open the door to the release of other environmental information relating to buildings. “There’s been a tendency to consider information about property and buildings to be personal information,” the spokesperson said. “We think that’s a misinterpretation of what personal information is. We hope that this will be a precedent in relation to other areas of environmental information.” • (above) Radon testing kits are available for less than €50 in Ireland.

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Energy Awards finalists include NZEB & retrofit projects Pappan Grove, a 35-unit NZEB apartment scheme procured from Cosgrave Group by Tuath Housing for social housing.

he Cosgrave Group, ESB and SSE Airtricity Energy Services, are among the finalists in the SEAI Energy Awards 2020. The annual awards recognise and reward excellence in sustainable energy in business, communities, research, buildings, renewables and the public sector. Twenty-four applicants across eight categories have been shortlisted, with the winners to be selected by a VIP judging panel in the coming weeks. Winners will be named at the awards ceremony in mid-October. The finalists were chosen for their innovative sustainable energy solutions and for inspiring energy action among colleagues and peers. The Cosgrave Group, ESB and SSE Airtricity Energy Services are finalists in the Energy in Buildings category. The Cosgrave Group has built an impressive energy efficient development consisting of 251 A2 rated apartments in Santry, Dublin. The homes at Bridgefield and Pappan Grove include renewable heating, heat recovery ventilation systems, airtight and thermally broken building details, and a district heating system that includes combined heat and power units and heat pumps. ESB Engineering & Major Projects is a finalist for the ESB Archives facility on St Margaret’s Road, Finglas, which SEAI said combined the highest level of energy efficiency with meeting strict functional performance criteria as an archive facility. SEAI also praised SSE Airtricity Energy Services’ Moyola Court retrofit project as helping to bring old inefficient properties owned by Dún Laoghaire-Rathdown County Council back to life. Fergus Sharkey, head of business and public sector with SEAI said: “Each year we are blown away by the quality of entries to the SEAI Energy Awards and this year has proved no different. We received 125 entries

from businesses, communities, and organisations across the country who are leading the charge, reshaping our communities and businesses, and inspiring each and every one of us through their action.” John Sisk & Sons will contest the headline Energy Manager of the Year award. Sisk Group energy manager, Ian O’Connor, has led the company to become the first construction company in Ireland to achieve certification to ISO 50001. The company is aiming to become zero carbon. SOLA Energy Solutions is a finalist in the ‘Small and Medium Business – Exemplary Energy Management’ category. SOLA purchased a building in late 2018 to develop into offices and a showroom. They showcased how a small business can transform an old inefficient building to become A-rated through implementing energy efficiency measures and renewable technologies. Other finalists include: 1 E nergy Team / Manager of the Year: Astellas Ireland Kerry Plant and Johnson & Johnson 2 L arge Business: Danone Wexford, Wyeth Nutritionals, and Boston Scientific 3 S mall and Medium Business: Finian O’Harte Poultry and Terra Spirits & Liqueurs 4 P ublic Sector: Dublin City Council, NUI Galway and Ervia Business Services 5 Inspirational Energy Community: Lárionad Acmhainní Nádúrtha CTR, Dunleer Sustainable Energy Community and Leitrim Cróga (Ballinaglera SEC) 6 I nnovative Deployment of Renewable Energy: Aurivo Consumer Foods, Green Generation and Energia 7 E xcellence in Energy Research and Innovation: NUI Galway, Glasport Bio and International Energy Research Centre (IERC). •

NEWS

Ballymore to deliver mooted zero carbon Guinness Quarter

iageo has chosen developer Ballymore as its partner to deliver the transformation of 12.6 acres of its iconic St James’s Gate site into the first “zero carbon” district in Dublin. A joint statement from Diageo and Ballymore said the companies will work together on a shared vision for the Guinness Quarter that will preserve the “heritage assets” and create an inspiring urban neighbourhood, which will open up the historic St James’s Gate site to the people of Dublin and beyond. The project’s zero carbon plans will involve re-using some of the existing buildings and examining all available renewable energy sources and how “zero energy ratings” can be met. The statement said the Guinness Quarter will “spread the heart and soul of Guinness across Dublin and beyond” – with a seamless union of residential living, community, entrepreneurship, creativity, sustainability, commerce, culture and generous new public space”. It added: “This regeneration will reshape and extend the heart of the south inner city, and act as a catalyst for the further regeneration of the wider Liberties area, and Dublin as a whole.” Ballymore was selected following a “rigorous and thorough” search by Diageo since the autumn of 2017. The selection process evaluated potential partners on the basis of their ability to deliver against Diageo’s vision to “open up a portion of the historic brewery site, using new and existing buildings to create a dynamic mixed-use urban quarter that will include residential, office, cultural and commercial spaces, fully integrated into the wider Liberties area”. Diageo Ireland managing director Oliver Loomes said: “St James’s Gate is a unique and extraordinary place. We are committed to a long-term sustainable future for the site and are delighted to be moving closer to our vision of opening streets, creating spaces and generating opportunity in the Guinness Quarter. As we move into the next chapter of this 261-year-old brewery, we are very excited about the possibilities of creating a quarter that will form part of the fabric of the city for generations to come. Since our announcement in 2017, we have been committed to doing it right and know that Ballymore share our vision for the future of the site. We look forward to partnering with them on this exciting project. Our ambition is also to work with the Iveagh Trust, one of Dublin’s largest social housing providers, as a partner in this project.” •

(above) A rendering of the proposed Guinness Quarter scheme at the St James’s Gate site.

ph+ | news | 17

NEWS

PA S S I V E H O U S E +

Why join the PHAI? Architect Simon Bell of the Passive House Association of Ireland outlines how the organisation can help clients, professionals and suppliers to deliver the passive house standard.

he impact of global climate change and the Covid-19 pandemic are challenging us all to think differently about how we live, the places we design and build, and ultimately the legacy we leave. With a need to act fast to reduce carbon emissions and respond to client demands for better buildings. The industry must upskill, learn from the pioneers, and develop experience in delivering buildings successfully to passive house or NZEB standard. These approaches have expanded from the realm of the aspirational eco house self-builder to all building typologies including schools, offices, factories and even swimming pools. Of course the industry isn’t fully prepared to

others as well as promoting the experience and innovation within the PHAI membership. Members of PHAI receive automatic membership to the iPHA and its related resources. These include the useful Passipedia, an online library of specialised passive house knowledge; the iPHA forum offering the opportunity to engage and share with other professionals worldwide; access to the excellent iPHA webinars often covering pioneering projects and building types, and of course discounts on the International Passive House Conference which is now scheduled to take place online from 20 September to 8 October.

• •

• • • •

More than ever the construction industry must work collaboratively to deliver buildings to higher standards. deliver to these standards yet, not everyone has the necessary skills or experience, there may be limitations with product availability, and some project types just haven’t been delivered to a standard like passive house before. More than ever the construction industry must work collaboratively to deliver buildings to higher standards, with better outcomes for residents or users. The Passive House Association of Ireland (PHAI) exists to promote the passive house standard, and passive house principles as an approach to delivering NZEB, and to support clients, professionals, contractors and suppliers in delivering high performing buildings. It has educated, facilitated discussion, shared knowledge, lobbied government and supported research across Ireland and Northern Ireland. PHAI recently submitted a paper in response to the call for evidence for the energy strategy being developed by the Department for the Economy in Northern Ireland, and we look forward to engaging with the department as that strategy is developed. PHAI is an affiliate of the International Passive House Association (iPHA), which is the global passive house network established by the Passive House Institute to advance the standard. Through this affiliation PHAI is connected to 18 other passive house organisations around the world, providing the opportunity to learn from

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PHAI membership enables individuals, practices, companies and public bodies to be part of this community and to contribute to its growth. Only through the support of its membership can PHAI continue to undertake the work that it does.

•

groups and other committees, thus influencing policy Be able to attend exclusive meetings to develop strategies and proceedings Have logo and name associated and displayed on all relevant Passive House Association of Ireland research material published on our website Be able to use the Passive House Association of Ireland logo on marketing materials Free half page editorial per year in Passive House Plus magazine Opportunity to promote at PHAI briefings which take place throughout Ireland and Northern Ireland Early access to Passive House Association of Ireland research and other outputs Network with leading passive house experts, practitioners and academics

PHAI is here to support you; engage with us, become a member, share your experience and your needs. With an experienced membership of individuals and companies as well as connections worldwide, PHAI can help to ensure your project is a success. We look forward to sharing some exciting plans in relation to guidance, training, software and STEM support in future editions of Passive House Plus. •

Standard membership offers the following benefits: • Automatic membership to the iPHA and related resources • Free subscription to Passive House Plus magazine • Discounts to upcoming events and certain publications • Access to passive house research and other outputs • Networking opportunities • Benefit from promotion and marketing by the association through our website • Part of a lobbying group to influence government policy • Increased professional exposure and credibility • Use of passive house logo For those who wish to support the research work undertaken by PHAI, Patron membership has been established with the following benefits: • Automatically receive all the benefits of standard membership of the Passive House Association of Ireland & the International Passive House Association • Be invited to join our technical working

PHAI is delighted to welcome Senator Windows as our latest member. We look forward to their support and input.

AS P A S S I V EP H OSUI SVEE+ H O IUGSBEC+ U PNDEAW TS E

Building sector must show bold climate leadership

(above) A new housing scheme in Dunleer, Louth, that is certified by the Irish Green Building Council’s Home Performance Index, which includes a zero carbon standard incorporating both operational and embodied energy.

n late 2018, the IPCC issued a stark warning. It highlighted that limiting global warming to 1.5 C is crucial to avoiding the most catastrophic impacts of climate change. It also clearly established that achieving the goals of the Paris climate agreement will require action at an unprecedented pace and scale. To maximise the chances of limiting global warming to 1.5 C, all sectors of the economy must achieve significant emissions reductions, and the building sector must fully decarbonise by 2050. To support faster and more ambitious actions on climate, this year’s World Green Building Week (21 to 25 September) focuses on delivering net zero carbon buildings and neighbourhoods. As part of this campaign, the Irish Green Building Council (IGBC) is calling on the building sector, policymakers and governments to take concrete action for the decarbonisation of buildings. In particular, the IGBC is calling on Irish businesses and local authorities to take a leadership role and to sign up to the Advancing Net Zero Commitment. The commitment, which aims to see 100% uptake of net zero carbon buildings by 2050, challenges businesses and cities to ensure that all buildings they own, occupy and/or develop operate at net zero carbon by 2030. The technical solutions exist and are being applied to projects around the world. Some of these solutions are being showcased through live tours and webinars during World Green Building Week. Replays will be available on www.igbc.ie. To facilitate this transition, the IGBC has also developed a zero carbon standard for new homes. Home builders can now offer certified zero carbon homes to home buyers, through the zero carbon standard within the Home Performance Index certification. Besides energy efficiency, the new zero carbon standard considers the upfront carbon emissions associated with the construction of the homes. It also encourages home builders to measure how the homes perform after they are purchased and lived in. Bringing embodied carbon upfront Most of the industry and policy focus to date has been on tackling operational carbon, 29% of global emissions. But the construction of new buildings and infrastructure accounts for 11% of global carbon emissions, before they are even used or

operated. These ‘embodied carbon’ emissions result from use of carbon intensive construction products and wasteful practices in the design and construction process. A growing number of product manufacturers have produced environmental product declarations (EPDs) over the last few months. EPDs are a standardised way for manufacturers to display information on the environmental impact of building products, including global warming potential. Ultimately, EPDs allow architects and other building product specifiers to make more informed choices about the materials they use. To support net zero carbon buildings, the IGBC is calling on companies designing and developing buildings to ask for EPDs. Organisations such as Dublin City Council, John Sisk & Sons, Coady Architects, Wain Morehead Architects, Transport Infrastructure Ireland and BDP have already signed the IGBC’s EPD commitment. As part of this commitment, they have committed to ask for EPDs and to prefer products with EPDs where possible (within procurement rules). Retrofitting our existing building stock Ireland cannot achieve carbon neutrality by 2050 without decarbonising its existing building stock. Barriers to deep renovation are perceptual, technical and financial. Many homeowners cannot afford to do everything at once or are limited by the need to continue to live in the house while work is being done. Even when attractive financing options are available, these are not necessarily enough to spur people to overcome the difficulties they perceive with undertaking energy efficiency upgrades. Next to the availability of finance, property owners are often confronted with a lack of awareness about the costs and benefits of renovation, and with a lack of understanding of the process — what to do, where to start, which measures to implement and in which order. To address this issue, the IGBC, with support from SEAI, is exploring the opportunity of introducing a building renovation passport (BRP) in Ireland. BRPs are masterplans for retrofit and include a record of works. By providing a set of actions, sequence and estimated costs, to inform improvements towards more energy efficient homes, they address the barriers to consumer decision-making. They can also embed the longterm ambition (2050 carbon neutrality target) into the short and medium-term steps of renovation. A building renovation passport has been piloted on 20 single-family dwellings across Ireland over the last six months, and a comprehensive feasibility study is currently about to be published. With less than ten years to address the climate crisis, all of us have a role to play. Whether it’s raising awareness on how buildings can tackle the climate crisis, sharing experiences and best practice, or showing leadership through the advancing net zero or EPD commitment, we encourage you to get involved in World Green Building Week 2020 and to #ActOnClimate. •

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Contact us for more information on how your brand can feature in our next issue. To enquire about advertising, contact Jeff Colley on +353 (0)1 2107513 or email jeff@passivehouseplus.ie

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ph+ | igbc ph+ update | news | 19

NEWS

PA S S I V E H O U S E +

Deep retrofit plans:

THE CURRENT STATE OF PLAY The need for decisive movement on deep retrofit has never been more pronounced, given the twin needs for urgent, radical action to tackle the climate crisis and jobs-intensive stimulus at a time of great uncertainty caused by the pandemic. The Department of Communications, Climate Action and Environment sheds light on its progress in delivering on the government’s deep retrofit pledges.

he Programme for Government set ambitious targets for the number and depth of residential retrofits to be completed by 2030. The targets are to retrofit 500,000 homes to a Building Energy Rating of B2 and to install 400,000 heat pumps in existing buildings over the next 10 years. These targets are expected to achieve the Climate Action Plan target of reducing the greenhouse gas emissions from the residential sector from 6Mt CO2e in 2017 to 3-4Mt CO2e in 2030. The Government sees retrofitting homes as a key element of Ireland’s economic recovery. It is a highly labour-intensive industry and creates quality sustainable jobs in local communities throughout the country. Increasing the numbers of homes retrofitted will also reduce greenhouse gas emissions from the residential sector as well as making homes more comfortable and delivering health benefits. Delivering on Ireland’s retrofit targets is a complex programme of work with a wide range of interlinkages and interdependencies. That is why a cross-departmental Retrofit Taskforce has been established to develop a new retrofit delivery plan capable of achieving the abovementioned targets. This process is well underway and has included reviewing the experience of existing retrofit support schemes in Ireland, consultation with stakeholders and an analysis of relevant international experience. The plan being formulated aims to address barriers to energy efficiency investments in four distinctive areas: customer proposition and demand generation, financing and affordability, supplier capacity, and delivery structure. The modelling carried out as part of the development of the National Energy and Climate Plan shows that in order to attain the 2030 residential energy efficiency targets, retrofitting needs to be scaled up significantly and rapidly to an estimated level of 33,500 B2 retrofits per year by 2022 and 56,000 per year by 2024. The Programme for Government committed to ring-fencing a significant

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portion of future carbon tax receipts for a new €5 billion socially progressive retrofit fund targeting all homes but with a particular emphasis on social and low-income tenancies. While this is clearly a significant level of Exchequer investment, it is generally acknowledged that more private investment will be necessary to meet the level of retrofit and heat pump installation required. Detailed Exchequer funding allocations will be agreed in due course as part of the annual estimates process and will

and expanded retrofit schemes later this month. In addition, a significant level of investment in training and skills development will be required to support progress towards achieving 2030 retrofit targets. In this regard, the Department of Education and Skills will invest €500,000 in programme seed funding for the development of new reskilling and activation courses that will be rolled out in 2021. The Department has also committed to finalise the new Apprenticeship Action

By announcing this additional funding, the Government has provided certainty to the sector so that they can continue approved programmes of work, bid into new and expanded schemes, maintain a pipeline of retrofit activity, and sustain and create jobs.

be published in the Revised Estimates Volume, subsequent to Budget Day. We recognise the need for multi annual funding and the July stimulus package commits to increasing the SEAI budget by €100 million in 2021. This money will be focused on community retrofit schemes, and retrofit schemes supporting those in energy poverty, as well as other initiatives to support the achievement of our retrofit targets. Initial estimates suggest that this investment will result in an extra 3,500 houses being retrofitted to a Building Energy Rating of B2, and up to 3,500 additional upgrades to homes of those living in energy poverty, as well as creating 3,200 direct and indirect jobs. By announcing this additional funding, the Government has provided certainty to the sector so that they can continue approved programmes of work, bid into new and expanded schemes, maintain a pipeline of retrofit activity, and sustain and create jobs. The SEAI will be announcing the first details of the new

Plan before the end of 2020. The plan will set out a programme of actions to secure an expansion of apprenticeship recruitment by the public and private sectors. Given the massive ramp up required in the national retrofit programme, the action plan will focus strongly on this sector. Consumers wishing to invest only in a selection of energy efficiency measures rather than a full deep retrofit work package will be able to continue to do so in the foreseeable future. However, in line with the Climate Action Plan commitment, the existing grant schemes will be reviewed and redesigned to ensure alignment with Government climate objectives and value for money. The transition towards the new retrofit delivery plan is expected to be industry-led. This means that the Government will endeavour to ensure the right market conditions prevail for the retrofit industry to upskill, scale up and develop in order to meet the expected growing demand. •

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ph+ | news | 21

MARC Ó RIAIN

COLUMN

The world’s first ‘zero energy’ house Returning to his regular series on the evolution of sustainable building during the 20th century, Dr Marc Ó Riain takes look at the first serious attempt to build a house with net zero energy use.

uring the 1973-74 oil crisis Denmark, which was massively impacted by the quadrupling of energy prices, invested in applied energy conservation in building research. The NATO sponsored Lyngby ‘dth-nul-energihus/zero-energy-house’ near Copenhagen would be the world’s first attempt to create a measured ‘zero energy house’ (as calculated against space heating and domestic hot water demand). The Solar Energy Pilot Study (1973-78) zero energy house team was led by Professor Vagn Korsgaard from the Technical University of Denmark. The design involved two habitable structures (60 m2 each) linked by a glazed atrium (70 m2) which functioned as an unheated wintergarden. This was one residence, occupied and monitored for a year. Understanding that heat loss would drive heating demand the team opted to maximise energy conservation primarily through passive means, such as by envelope insulation and airtightness, augmented by passive solar heat gain, and heat emitted from internal loads like people and appliances. Augmenting this passive approach was the use of flat plate water-based solar collectors connected to a heavily insulated seasonal heat storage tank. What is surprising about this project is the standards of insulation and airtightness it achieved. Understanding the impact of infiltration on heat loss, the team opted to build the

We stand on the shoulders of such pioneers. structure with prefabricated sandwich panels insulated with mineral wool, to minimise field joints. The U-values were 0.14 for walls (300 mm insulation) and 0.10 for the floors and ceiling (400 mm insulation). There were also double glazed windows (U-value: 3.0) with night time insulated external shutters that targeted a U-value of 0.5 (but achieved 0.9 in practice due to thermal bridging). The team understood the need to weather-strip the windows to the panel walls and seal electrical conduits, resulting in an estimated 3 m3/hr/m2 airtightness at 50 Pascals. The mechanical heat recovery ventilation system then delivered 0.7 air changes per hour working at 70% efficiency. Each room had a TRV controlled fan coil unit with air passing over hot water pipes coming 22 | passivehouseplus.ie | issue 35

The Danish 'zero energy house', built in the aftermath of 1973-74 oil crisis.

from a 400 litre hot water tank, located in the 300 m3 seasonal storage tank (a tricky location to service). Run off from showers fed into the tank inlet, recovering only 20% of heat energy. An auxiliary electric 4 kW hot water heating system provided a backup. The main solar water array was a vertically mounted collector with black painted tubular radiator bars filled with water within a glass box, and insulated at the back. Water had to be drained from the system to protect against frost, and the glass actually fractured in its metal frame, breaking 20% of the array one February morning in 1976 due to the thermal differential. I found it surprising, given the existing published experiments with Solar 1 in MIT in the 1930s and the issues with the Dover Sun house in the early 1950s, that the researchers elected to go with water which would freeze, and glass which was prone to crack with heat differentials. The team ran the ‘Zero Energy House’ for a reference year with a calculated performance, and then ran it occupied by a family for a year as a measured performance. The occupants didn’t always close doors or windows, and sometimes forgot to close the exterior shutters, therefore space heat demand (SHD) was higher but strangely domestic hot water demand was much lower during the occupied year. The desktop estimation for SHD was 2,300 kWh/yr but the actual occupied SHD was 5,800 kWh/yr. The seasonal storage tank lost about 40% of its energy through transmission, and while the solar collectors worked quite well,

generation and thermal storage ran 20% behind calculations with less solar incident in the occupied year versus the previous reference year. For the occupied year solar thermal only covered 43% of the total space heat demand (5,800 kWh) and 27% (1,000 kWh) of the hot water load (2,700 kWh). The auxiliary electrical space heating and ventilation was 5,000 kWh. So in a real world test the ‘zero energy building’ did not achieve a net zero balance, it only achieved 55% of its target, but that was a critical first step towards zero energy buildings. The team used super-insulation, recognised thermal bridging, achieved good airtightness and used heat recovery ventilation. The complicated active systems like solar water and seasonal storage tank were prone to damage and efficiency issues, and were extremely expensive. However, they pointed the way for the rest of us and we stand on the shoulders of such pioneers whose legacy we are only seeing in mainstream construction today. n

Dr Marc Ó Riain is a lecturer at the Department of Architecture at Cork Institute of Technology, one of the founding editors of Iterations design research journal and practice review, a former president of the Institute of Designers in Ireland, and has completed a PhD in low energy building retrofit, realising Ireland’s first commercial NZEB retrofit in 2013.

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DR PETER RICKABY

COLUMN

Will we really build back better? As governments rush to jump-start their economies, there is a danger that important lessons for how to retrofit homes will be lost in the rush to build. But there is a better way, writes Dr Peter Rickaby.

wrote in my last column about how lockdown provided a glimpse of a more sustainable future. I also predicted a battle between those who want to put everything back exactly as it was, and those who want us to learn lessons for sustainability. We are now in the battle of the three Bs: for bankers, business bosses and politicians it’s ‘build, build, build’, but for others it’s ‘build back better’. In between there are a lot of people who just want their jobs and social lives back. In recent weeks I have participated in many meetings, on both sides of the Irish Sea, about how we might use domestic retrofit to create jobs while simultaneously reducing emissions. After more than twenty years promoting domestic retrofit as an essential element of sustainability, with barely a flicker of response in Whitehall and little enthusiasm elsewhere, now everyone wants it yesterday! It’s like waiting for the number two bus in Milton Keynes (which I did often, before lockdown): I stand at the stop for an hour, then three buses come along at once. In the UK, we have spent ten years and at least £20 million learning how to do domestic retrofit well: how to identify and manage risks, how to eliminate the performance gap and how to protect the buildings and the health and wellbeing of occupants. Thousands of people have contributed, starting with the Retrofit for the Future and Scaling Up Retrofit competitions, then the

but not much about how to do it at scale. If we are to retrofit nearly thirty million homes, well-managed processes are going to be as important as good designs and specifications. Imagine how exhilaration turned to horror when I learned first that the UK Government has allocated £1.5 billion to creating jobs for unemployed workers by insulating between 150,000 and 600,000 homes by March 2021, and then that the industry is lobbying to relax or abandon the quality assurance framework for the sake of speed and profit. As I write, the argument goes on. By the time this is published we will probably know how it turned out, but if ministers give in to the temptation to dilute hard-won standards then it will be down to them when it goes wrong for householders. What is disappointing about this episode is that even after throwing nearly £3 million into improving standards and managing risks, some people in the UK government still seem to think that retrofit is an easy process that they can use to create jobs simply by throwing money at it. In reality, retrofit is complex and risky, and they are gambling with people's homes and lives. We are told that there may be more to come for retrofit in 2021, on a larger scale. Many friends and colleagues in the UK and Ireland are now working on proposals for national domestic retrofit programmes, and they are including the latest standards. Two interesting ideas have emerged from this work.

The idea is simple: lead with ventilation, before improving the fabric. Green Deal Communities programme, followed by the Each Home Counts review, the establishment of the TrustMark quality assurance framework and the retrofit standard PAS 2035, and recently the retrofit supply chain pilots and the government’s whole house retrofit competition. In Ireland, the deep retrofit pilots also taught us a lot. Along the way we have had some disasters: in Glasgow, Edinburgh and Preston, at Grenfell Tower, and in thousands of homes ruined by inappropriate or poorly installed insulation. All this work, money and misery have taught us how to deliver good retrofit,

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The first idea springs from the lack of skilled capacity in the retrofit industry, and the need to allow time for training before we deliver at scale. The point is that the quality of retrofit reflects the quality of the original assessment of the dwelling. The idea is to separate assessment from the rest of the process and deliver free or subsidised whole-dwelling assessments, improvement option evaluations and retrofit plans. These assessments, running ahead of retrofit itself, would engage households, provide knowledge of the stock, establish a pipeline of work to encourage investment and

finance, and allow time for retrofitters to be trained. The second idea springs from two maxims: ‘fabric first’ and ‘no insulation without ventilation’. Improving the building fabric, to reduce demand, before moving on to decarbonise and improve the efficiency of building services, has always made sense. Now, with so many uncertainties about 2050 (will the electricity grid be completely decarbonised? will we have affordable batteries? how far will low-carbon heat networks penetrate?) fabric first makes even more sense – but not without ventilation. It is essential when insulating to replace lost infiltration and ensure good indoor air quality by improving ventilation. In the age of Covid, ventilation looks even more important. Effective ventilation also deals with the condensation, damp and mould (CDM) problems that many homes suffer from, which insulation alone will not fix. So the idea is simple: lead with ventilation, before improving the fabric; make homes safer for installers and deliver immediate improvement by eliminating CDM first. This approach was successful at Thamesmead in south-east London, the Northern Ireland Housing Executive is trying it in homes outside Derry, and the same approach is about to be applied to several hundred mouldy flats in south London. Domestic retrofit has a long way to go, and we may have more disasters, but in the UK we now have the quality assurance framework and technical standards to avert them. Insisting that those standards are applied will help to improve our housing and protect the health and well-being of residents. n

Dr Peter Rickaby is an independent energy and sustainability consultant. He helps to run the UK Centre for Moisture in Buildings at University College London, chairs the BSI Retrofit Standards Task Group, and is active in training building professionals in retrofit coordination and risk management.

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CASE STUDY

SOUTH DUBLIN

ZE R O IN INSPIRED DESIGN OFFERS ROUTE TO NET ZERO ENERGY LIVING

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t’s hard to know where to start with Mel Reynolds’ new house in Dún Laoghaire. The first passive house ‘plus’ build in the country, it was financed with a crowd-sourced funding model. Its reconfigurable ground floor layout anticipates a range of human needs, and yet it still manages to achieve a far more efficient use of space than your traditional semi-d. And because it delivers so much in a tight footprint, it offers developers a scalable model of highly efficient land use at no additional cost. Perhaps the most striking thing however is the symbiosis Reynolds discovered between his take on the passive house plus

FRONT ELEVATION FRONT (NORTH) ELEVATION (NORTH)

standard and the operation of an electric vehicle. The savings – in both cash and CO2 – are jaw-dropping. More about that later. Let’s start with some detail. This is a 120 m2 four-bed passive mews house built in the garden of Reynolds’ existing Sandycove home, which is itself a protected structure located in an architectural conservation area. The new mews house is of single leaf masonry construction with external wall insulation. It comfortably meets the passive standard, and with the addition of a sizeable PV solar array, is set to be certified as passive house ‘plus’. This recently-introduced version of the standard requires a minimum of 60 kWh/m2/yr of renewable

energy generation on site. Finance for the build was raised through Property Bridges, an Irish organisation set up in the aftermath of the 2008 crash to step into the space the banks had largely vacated. It provides peer-to-peer loan finance for construction projects. Individuals can invest relatively small sums which are then repackaged into loan finance for specific projects. Reynolds’s house was the very first to be funded by the platform. This is a mews house, and mews houses, as Reynolds points out, are typically quite austere and self-contained because they don’t tend to have a much of a streetscape to engage with. You’re also talking about a very

ph+ | south dublin case study | 27

SOUTH DUBLIN

CASE STUDY

compact infill site, overlooking not alone the existing family home but also adjoining houses in quite a densely populated suburb. This led to what he describes as an ‘introverted’ design, with no overlooking windows. “I was looking not alone from our point of view, but from the point of view of surrounding neighbours.” Smart use of space It’s also an ‘upside down’ house. Bedrooms on the ground floor, kitchen and living area on the first floor. “People assume that this is an aesthetic decision,” says Reynolds, “and it is, it’s an interesting way to live, but it actually is far more efficient internally in terms of your net usable space.” He points out that the statistic that we all zero in on – floor area – can be misleading. Net usable space, on the other hand, removes hallways, bathrooms, ensuites and undercrofts, giving you a more meaningful metric. The regulations insist on a bathroom on the same floor as the main entrance. Since this is now downstairs with the bedrooms, the main bathroom fulfils this role and there’s no need for any WC upstairs. The only circulation space, therefore, is the stairs ascending to the first floor. “The net to gross ratio of circulation and service spaces to usable spaces in a typical four-bed semi-d or five-bed three-storey is between 30% and 33%. In this arrangement, it’s 20%. So you effectively get an extra bedroom by just inverting the layout...So even though this house has 120 m2 square metres gross space, internally, it’s the equivalent of about 135 m2.” Throughout the build, Reynolds also

28 | passivehouseplus.ie | issue 35

CASE STUDY

Getting the right builder was critical to achieving the required airtightness.

Photography: Paul Tierney / Abdone.com

looked at the project with a developer’s eye; in terms of materials, in terms of design, in terms of logistics. The ‘introverted’ design and the highly efficient use of space make the proposition much more attractive to a developer willing to use a different cookie cutter. Reynolds estimates that you can get 30% greater density with this design, and it’s hard to see what you’d be giving up for that. He originally conceived the project as a sort of trade down home for an older couple, but as he began to work through the design, he realized that the possibilities were much wider. “I tried to imagine a client in order not to get bogged down with what I wanted. But there was always that tension between would it be for a couple or for a family?” Rather than resolve that tension, he decided instead to try to “future proof for different occupancies”. Was there a way to configure the house so that it could meet the needs of a family or couple or... whatever? The answer was yes. Downstairs, the rooms can be reconfigured into no fewer than 16 different layouts, from five bedrooms to a single master suite. This is done using a combination of folding partitions and ‘soft spots’, built-in openings in walls which can be disassembled and reassembled very easily. “One of the issues with residential schemes is that they’re very rigid,” says Reynolds. “If it’s a one-bed apartment, it’s always going to be a one-bed apartment. The same if it’s a co-living unit, a hotel room or a bedsit. None of these spaces can become anything else without significant

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modifications. I was interested in this idea of resilience in the built environment. I wanted it to be a comfortable house for either a couple, a small family or a large family... So the design challenge was how do you fit a four-bed semi-d on a 135 m2 site with two car parking spaces, 60 m2 of garden space and a flexible interior?” All of this is great in theory of course, but could a large family live comfortably in this space? Is it simply too small to work? It was to answer this question that Reynolds and his family of six (partner plus four children) decided to move in. He sold the idea to the kids by offering them their own rooms – something they didn’t have in their existing house, despite the fact that it’s got twice the floor area. Similarly, despite the compactness of the design, there is more storage space in the mews house than in the old house. All of the design work evolved under the constraint of a passive standard thermal envelope. As far as the build went, Reynolds brought to bear all of the work he had been doing in the previous two decades, refining details and arriving at a fabric spec that would achieve the necessary targets as simply as possible. Super insulated masonry He opted for single leaf masonry with external insulation, a specification he has been using since 2008, combining Quinn Lite thermal blocks with Kingspan phenolic external insulation and acrylic render to deliver passive house U-values.

ph+ | south dublin case study | 29

SOUTH DUBLIN

CASE STUDY

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VENTHEAT 30 | passivehouseplus.ie | issue 35

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CASE STUDY

Quinn’s low thermal conductivity aerated concrete blocks have been used for years as the first course on many masonry builds as a mean of eliminating thermal bridging between the walls and the floor slab. But since 2018 the company has been promoting the use of Quinn Lite blocks with external insulation for single-leaf, whole-wall construction, dubbing it their “super insulated masonry solution”, or SIMS. “By using Quinn Lite as the masonry substrate, you’re automatically improving the thermal performance or U-value of the walls, while at the same time significantly reducing thermal bridging throughout the building,” says Jason Martin of Quinn Building Products. Single-leaf blockwork also helps to speed up the build, with the lightness of aerated blocks making things easier again. “In relation to the speed of build, if you compare it to typical cavity wall construction, you’re using half the number of blocks. For a square metre of wall, you only need ten blocks, so first off, it’s much, much quicker than building a traditional cavity wall,” says Jason Martin. Reynolds also says that aerated blocks contribute to faster drying time, and even though they cost more per block, the need for less blocks and less labour makes it cost neutral overall. As is frequently the case, airtightness was a challenge, and was met in this case with a Blowerproof liquid airtight membrane, which Reynolds discovered in the pages of Passive House Plus. This is a BBA certified product with Class C fire rating and is well established in Europe. While the normal fire compartmentation requirement with a build-up like this would be to batten out the walls internally and then mechanically fix plasterboard to the battens, Reynolds established that it was acceptable in this case to use dabs of adhesive to glue the plasterboard directly to the Blowerproof-painted walls, because Quinn Lite has a four-hour fire rating on its own. This helped save valuable floor space as well as speed up the build. He admits that getting airtightness down below the magic 0.6 ACH at 50 Pa can be time consuming and tricky, but that it’s uniquely worthwhile. He says getting the right builder was critical to achieving the required airtightness. “The builder Sean Regan had comple-

Downstairs, the rooms can be reconfigured into no fewer than 16 different layouts.

ted the Passive House Academy’s tradesperson course and had two skilled foreman, John Gorry and Sean Whelan, who both had training in airtightness. Without this essential upskilling on the contractor’s side it would have been very difficult to get to this level of quality, particularly the airtightness.” Ultimately the team’s prior experience paid off. “The airtightness was the most challenging aspect,” says contractor Sean Regan. “It was just about being meticulous and checking and rechecking. It was our first time using Blowerproof, but it was very convenient around window openings and tricky corners.” The same team — Reynolds and contractor Sean Regan — is now working on a passive retrofit project in Rathgar, again using Blowerproof for airtightness. Passive house ‘plus’ Reynolds refers to both Madeira Oaks, a 2016 passive development in Enniscorthy by Michael Bennett, and Silken Park, a

SOUTH DUBLIN

Durkan Residential passive house development in City West, as inspirations behind this project. “These showed us that if you can hit passive levels of fabric performance, you don’t need a primary heating system, you can do it using an airborne system. So straight away, if you can spend a little bit more on your walls, particularly on glazing, and make it airtight, you can eliminate your boiler and save about fifteen thousand euros.” Reynolds’s next question was what to do with the savings. One possibility? Put it on the roof. He specified a very large solar PV array of 24 panels covering an area of 41 m2, with a power rating of 6.8 kW. Chatting to a neighbour about his plans, she mentioned that her dad worked with PV. This dad turned out to be Tim Cooper – one of the foremost experts in the country. Cooper agreed to come and look at Reynolds’ plans. This was his first question: ‘What are you going to do with the power? If your house is efficient, you’ll be exporting most of it.’

ph+ | south dublin case study | 31

SOUTH DUBLIN

CASE STUDY

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info@blowerproof.ie - www.blowerproof.ie - 0404 61901 32 | passivehouseplus.ie | issue 35

CASE STUDY

SOUTH DUBLIN

CONSTRUCTION IN PROGRESS

The foundations spec includes 1 a concrete trench; 2 perimeter of Quinn Lite and Foamglas blockwork; 3 270 mm Kingspan K3 insulation followed by reinforced concrete slab mesh; 4 corner detail showing XPS insulation enclosing the first layer of Quinn Lite block. 5 Singleleaf Quinn Lite blocks form the whole walls, significantly reducing thermal bridging throughout the building. 6 Kingspan phenolic external insulation helps to deliver passive house U-values; 7 & 8 200 mm Kingspan external wall board insulation is fitted to the soffit at the overhang and undercroft; 9 Compacfoam supports to window reveals minimise thermal bridging.

By Cooper’s calculations, between 60% and 70% of the power would be going back to the grid. Moreover, the way electricity demands varied from morning to evening, there would be days when Reynolds would both import and export power – and there remains no feed-in tariff in Ireland for microgenerators. Rather than scrap his plans, Reynolds asked Cooper if he would create a demand control model which would determine the most efficient way to use the power he intended to generate. Straight away, Cooper spotted a couple of easy wins. “Mel intended to use cold-fill washing

machines,” he says, “which would be heating up the water with electricity, and in an uncontrolled way. We decided to get hot-fill washing machines [which use hot water already generated in the home] so you could heat the water in an efficient way. That was step one.” Next, they made sure that all the electrical appliances had AAA energy ratings to cut instantaneous power use, thereby reducing potential demand on the grid. That done, they looked at the storage options, specifically batteries and thermal storage. “We did a lot of arithmetic,” says Cooper, “and concluded that the most efficient

way to do it in all respects was to put in an increased thermal hot water storage system and design it in such a way that it was fully optimised.” The house has a Pichler PKOM4 combi heat pump system supplying all space heating, hot water and ventilation duties. The Pichler unit has an integrated 212 litre hot water tank, but Reynolds and Cooper decided to install another 120 litre tank to increase the storage capacity for hot water generated by the solar PV array. The heat pump was also configured so that it always heats water in the coolest tank first, to maximise efficiency.

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CASE STUDY

34 | passivehouseplus.ie | issue 35

CASE STUDY

SOUTH DUBLIN

CONSTRUCTION IN PROGRESS

1 & 2 With the ground floor structure complete, work begins on the upper floor of the house which includes an outdoor terrace. 3, 4 & 5 the front door and hall, showing Blowerproof liquid airtight membrane being applied directly to the Quinn Lite blocks, and plasterboard fitted directly to the Blowerproof-painted walls. 6 Siga Majrex airtightness membrane and tapes around roof windows; 7 the Fakro walk-on roof windows are situated flush with the tiles of the first-floor terrace. 8 A Pichler combi heat pump system supplies all space heating, hot water and ventilation duties; 9 the large 24 panel solar PV array not only generates plenty of power to use around the home, it can also produce enough energy to run an electric vehicle for 10,000 km per year.

There is also a seven litre Quooker boiling water tank and associated tap, again powered by the PV. In addition, Reynolds installed a 4.8 kW solar battery pack. According to Tim Cooper’s model, total energy costs would come to €1,017 per year with six occupants if there was no solar PV. That’s 6,908 kWh of energy and 2,010 kg of CO2 for all space heating, hot water and plug loads. But when you bring in the combination of PV, thermal storage and battery pack, consumption of grid electricity drops by 70% to just €300 per year (2,244 kWh), with a surplus of 976 kWh being exported.

It was at this point that Reynolds began looking at the possibility of diverting that excess into an electric vehicle (EV). The figures which fell out of the model were fascinating. The house’s PV array could power the car for two-thirds of his annual mileage of 15,000 km, with one-third (5,000 km) coming from the grid at a cost of just €93. And this left the house exporting just 613 kWh of leftover solar energy back to the grid. “In effect,” says Reynolds, “at passive house mews a typical EV will have annual fuel bills of €93 for 15,000 km average annual driving, as opposed to an efficient diesel which costs €926 per year to run, and generates 1,871 kg

of CO2 for the equivalent mileage. Moreover, the passive house plus mews, plus EV actually emit three tonnes less CO2 than the average NZEB A3 home plus a diesel car.” The provisional BER assessment for the house also, remarkably, turned up ‘minus’ numbers for three of its key metrics — the primary energy demand, energy performance co-efficient (EPC) and carbon performance co-efficient (CPC). For example, while an EPC of less than 0.3 is needed for the house to comply with the nearly zero energy building standard in Ireland’s building regulations, assessor Jonathan O’Toole of OTE Solutions calculated a figure of - 0.334, indicative of

ph+ | south dublin case study | 35

SOUTH DUBLIN

CASE STUDY

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36 | passivehouseplus.ie | issue 35

CASE STUDY

the house’s superb thermal efficiency and self-sufficiency with on-site solar energy. But forget all that for a minute. What is it like to live in? Reynolds says that the house has been a big hit with the kids. Throughout the lockdown, they tended to gravitate towards the first-floor terrace, which you access through the kitchen and which operates as a kind of additional living room. “The one thing that gets me is the air quality. It’s like when you’re in Dublin and you go down the country. You get that lovely fresh air that knocks you out and after a week, you get used to it.” “It’s brilliant. It’s been a really positive, really interesting experience. I’d be very keen to do another one, I’d love to see if I can do something else with the next one.” Mel Reynolds is currently selling the passive house plus mews house to fund his next project. For enquiries contact peter.kenny@ie.knightfrank.com.

WANT TO KNOW MORE? The digital version of this magazine includes access to exclusive galleries of architectural drawings. The digital magazine is available to subscribers on www.passive.ie

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SELECTED PROJECT DETAILS Client: Louise Reynolds Architect & project management: Mel Reynolds Contractor: Sean Regan Ltd Quantity surveyor: Damian Bowers & Associates Services engineer: Conlon Engineering Structural engineer: Carraig Consultants Passive house & thermal bridging consultant: Earth Cycle Technologies Energy conservation consultant: Tim Cooper Conservation Engineering Passive house certification: Mead Consulting BER: OTE Solutions Health & safety: Safety Solutions Roofing: KD Roofing Mechanical sub-contractor: MountainLodge Mechanical Services Electrical sub-contractor: Thomas Kenny & Co Ltd Masonry: Quinn Building Products External render: Baumit UK Airtightness tapes & membranes: Siga

Airtightness membrane (liquid): Blowerproof Ireland Flat roofing: Moy Materials Masonry thermal breaks: Foamglas Steelwork thermal breaks: Armadillo Noise & Vibration Ltd GGBS concrete: Kilsaran FSC certified timber: Glennons Insulation (various): Kingspan Insulation Internal blinds: Curtain Traders MVHR: Pichler, via VentHeat Solar PV: Solartricity PV diverter & EV charger: Myenergi Windows & doors: Internorm, via Eco Window Concepts Metal fabrication: Dunfab Engineering Sanitaryware: Bathhouse Kitchens: Nobilia, via Timbercraft Rooflights: Fakro Landscaping & living wall: SAP Landscapes Ironmongery: KCC Architectural Rainwater harvesting: Wastewater Solutions

ph+ | south dublin case study | 37

SOUTH DUBLIN

CASE STUDY

Kingspan nZEB Ireland

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38 | passivehouseplus.ie | issue 35

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CASE STUDY

SOUTH DUBLIN

1 2

LEGEND

2 3 6

1 2 3 4 5 6 7

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GROUND FLOOR GROUND FLOOR

N 4

LEGEND

1 2 3 4 5 6

living dining kitchen stair v o i d te r r a c e e x t e r n a l stairs

EMBODIED CO 2 A lifetime embodied CO2 calculation of Cove Mews by Tim Martel using the AECB’s PHribbon tool delivered some interesting findings and provides a clear lesson that life cycle assessment results need to be treated with care and considered in context. The house scored a cradle to grave figure of 782.1 kgCO2e/m2 of the treated floor area (TFA), with 210 kgCO2e/m2 for the solar PV array alone – a figure which assumes the array would be replaced once within the projected 60 year life span in the calculation, and therefore doubles the associated embodied CO2 emissions. Given its comparatively compact size – certainly in its current six person family configuration – it’s worth considering that a much larger version of the house would have scored a significantly lower result per square metre, even if the absolute tonnage of embodied CO2e (carbon dioxide equivalent) increased. If the PV array is removed from the calculation, the score drops to 570 kgCO2e/ m2 TFA, which means it likely comfortably meets the RIBA 2030 embodied carbon target of 570 kgCO2e/m2 net internal area (NIA). According to Tim Martel TFA and NIA calculations tend to be very close. But might a substantially larger version of this house, with no PV array and a pair of SUVs in the drive, meet the RIBA 2030 embodied CO2e targets, even though such a house may arguably be far more polluting? Embodied CO2e emissions tend to be

calculated separately from a building’s operational energy use throughout its lifespan, meaning that in this case any extra embodied carbon invested in the high performance fabric and, in particular, the large PV array, are separated from the operational CO2e benefit they will deliver over time. That calculation isn’t simple, as grid electricity is on a trajectory of decarbonization. If we believe the projections, grid electricity will be CO2 neutral in the UK by 2033 and in Ireland by 2040, with microgenerators like the PV array at Cove Mews playing a central role in an increasingly decentralized energy system. This means there may be a self-defeating argument if the upfront embodied CO2e emissions of a PV array are found not to stack up due to future decarbonized electricity that they help to bring about. The operational CO2e savings at Cove Mews are considerable based on current electricity emissions factors. The clever integration of a low energy house, PV array and electric vehicle were compared to a notional alternative posited by Tim Cooper and Mel Reynolds: a minimum compliant NZEB home, drawing more heavily on dirtier grid energy, combined with a fossil fuel powered car, which Cooper has calculated to emit 3.88 tonnes of CO2e per year, more than three tonnes higher than the projected figure for Cove Mews plus an EV, in both cases based on an average mileage of 15,000 km/yr.

EMBODIED CO2e Cradle to Grave

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ph+ | south dublin case study | 39

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CASE STUDY

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ECO WINDOW CONCEPTS LTD 40 | passivehouseplus.ie | issue 35

CASE STUDY

SOUTH DUBLIN

IN DETAIL Building type: Detached 120 m2 externally insulated two-storey detached mews Location: Sandycove, Dún Laoghaire, Co Dublin Completion date: December 2019 Budget: Not disclosed Passive house certification: Passive House Plus certification in progress Space heating demand (PHPP): 15 kWh/m2/yr Heat load (PHPP): 11 W/m2 (Non-renewable) primary energy demand (PHPP): 75 kWh/m2/yr Primary energy renewable (PHPP): 58 kWh/m2/yr Heat loss form factor (PHPP): 4.29 Overheating (PHPP): 1.4% of year above 25C Number of occupants: 3 to 6 (design figure) BER: A1 ( - 60.30 W/m2K, provisional figure) Energy performance coefficient (EPC): - 0.334 (provisional) Carbon performance coefficient (CPC): - 0.317 (provisional) Environmental assessment method: Home Performance Index pending Estimated energy consumption: Using a maximum demand occupancy of six persons, Cove Mews would require 6,908 kWh (2,010 kg CO2) in total for all heating, hot water and consumer loads. Without thermal storage, it would export significant solar PV surplus to the grid of 4,550 kWh. When various demand/control options are deployed (water and battery storage) to optimise on-site renewable energy use, consumption of grid electricity reduces by two-thirds to 2,244 kWh (653 Kg CO2) and 976 kWh is exported to the grid. When an electric vehicle is then charged at the house, total use of grid electricity increases to just 3,008 kWh (875 kg CO2) for both house and car, assuming 15,000 Km mileage per year, and just 613

kWh is exported to the grid. CO2: House and electric vehicle combined emit 875 kg CO2 per annum. For comparison, a typical NZEB A3 rated home with an efficient diesel car emits 3,882 kg CO2, over three tonnes more CO2 annually, based on current Irish CO2 intensity factors. Energy bills (measured or estimated): Based on detailed demand-control model with occupancy of 6, annual bills for all energy consumption are estimated at €300. Space heating and hot water account for €0 of this as these are fully met by the PV array. When electric vehicle (EV) charging is added, total imported energy costs rise to €393, which assumes 15,000 km for EV. Running costs are unit charges plus VAT, do not including standing charge or PSO levy. Assumes state-of-charge based smart charging of the EV. Airtightness: 0.57 air changes per hour at 50 Pascals Thermal bridging: Foamglas courses used in foundations to limit thermal bridging, Quinn Lite blockwork throughout with Compacfoam supports to window reveals (glazing positioned in external insulation zone), Alma-T to all thresholds below DPC level, Armadillo thermal-break pads to steel column connections. All service cavities filled with Metac insulation to reduce thermal looping. Letterbox and drainage all external to building envelope and garage gate externally mounted with no connections to building. Ground floor: 150 mm thick 50% GGBS reinforced concrete slab insulated with 270 mm Kingspan K3 insulation. U-value: 0.1 W/m2K Walls generally: Acrylic external render externally on 140 mm Kingspan Kooltherm external wall insulation, on 215 mm Quinn Lite B5 blocks, on 12.5 mm plaster, on 15 mm dabs internally. U-value: 0.12 W/m2K North wall: Acrylic external render on 200 mm Kingspan Kooltherm external wall insulation, on 215 mm QuinLite B5 blocks, on 12.5 mm plaster, on 15 mm dabs internally. U-value: 0.09 W/m2K Roof and upper deck: Paralon NT4 2 ply roofing membrane, on 120 mm Paratorch insulated board, on 18 mm OSB, on timber

joists with 15-90 mm Isover Metac mineral wool insulation on 210 mm infill Kingspan Kooltherm K7, on 15 mm OSB board to underside, on 25 mm service cavity, on 12.5 mm plasterboard. U-value: 0.1 W/m2K Undercroft Soffit (upper floor to external area below): Acrylic external render, on 200 mm Kingspan EWB insulation, on 15 mm OSB board, on timber joists with 300 mm Isover Metac mineral wool insulation to services zone and 210 mm interstitial Kingspan Kooltherm K7 insulation, on 15 mm OSB, on 10 mm cement board, on 20 mm ceramic tile finish over. U-value: 0.07 W/m2K Windows: Internorm triple glazed aluminiumclad oak windows, with argon filling and an overall U-value of 0.73 W/m2K; G value 0.6 Roof windows: 2 x Fakro DXW DW6 triple glazed flat roof ‘walk-on’ windows. U-value: 0.7 W/m2K Heating & ventilation system: Pichler PKOM4 heat pump combi unit, Passive House Institute certified to have heat recovery rate of 85% (dry heat recovery 88%) supplying ventilation, space heating and hot water with 212 litre integral HW tank (av. storage tank temperature 45 C. Secondary water storage: Secondary 120 litre tank and 7 litre Quooker Combi independently heated from PV array. Water: FLine Diver 5, 000 litre rainwater harvesting tank supplying all irrigation and WC. All sanitary fittings are low-flow 9 litres per min. Electricity: 41 m2 (24 x 340 Wp) LG Neon solar photovoltaic array roof-mounted at KD-D-Dome system with average annual output of 6.8 kW, Solis inverter and Pylontec 4.8 kWh battery storage. MyEnergi Eddi diverter, MyEnergi Zappi smart EV charger and MyEnergi Hub. Green materials: 50% GGBS cement used in all insitu-concrete, aerated blockwork throughout with FSC certified timber in all areas. Biodiversity enhanced with the installation of ‘Living Wall’ and Acacia screen planting to upper level terrace along with mature specimen Magnolia at ground level. All ground surfaces are permeable along with re-surfaced lane which is water permeable asphalt.

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CASE STUDY

BUILD WITH EASE, BUILD WITH SPEED, BUILD WITH CONSCIENCE

Build with SIMS SIMS by Quinn is a simple solution which brings established European best practise construction methodology to Ireland. The solution delivers a huge range of advantages which ensure SIMS as a must consider option for any new build in Ireland.

BUILD WITH EASE… • Straightforward construction method which utilises the simplicity of single leaf construction whilst enhancing the thermal performance and weather tightness of the building • Utilises existing blocklaying skills • Less labour intensive build: lighter blocks, half blockwork required • Complete support from Technical by Quinn team

BUILD WITH SPEED… • Up to 60% faster than traditional cavity wall construction & comparable with timber frame - 50% less blocks to build - 20% quicker build method if using thin joint mortar - No wall ties, DPCs or insulation to slow the block layer down - No outer leaf to be constructed • Brickwork or external cladding removed from the critical path permitting access for finishing trades much sooner in the build schedule • Pair of semi-detached houses ready for roof in 10 working days including installation of precast concrete first floor 26 | passivehouseplus.ie | issue 35

The finished building has lower energy consumption with lower carbon emissions, resulting in less environmental impact BUILD WITH CONSCIENCE… • A more sustainable, modern method of construction whilst utilising traditional skill set • The finished building has lower energy consumption with lower carbon emissions, resulting in less environmental impact • SIMS can easily achieve stringent regulatory requirements which demand superior performance in relation to energy consumption, such as nZEB or passive house standards • Quinn Lite blocks are made from up to 80% recycled materials • Quinn Lite are among the first products in Ireland to have published Environmental Performance Declarations (EPDs) • Quinn Lite blocks are manufactured using locally and responsibly sourced raw materials.

CASE STUDY

SOUTH DUBLIN

quinn-buildingproducts.com/sims-by-quinn

BUILD FOR LIVING BUILD FOR PERFORMANCE BUILD FOR THE FUTURE

Build for Life Thermal performance: Heat loss through thermal bridging reduced by up to 80%

BUILD FOR LIVING… • • • •

Far superior comfort levels with a super insulated home No drafts, no damp / mould, so healthier living environment More economical to run with reduced heating costs Quinn Lite blocks have optimal thermal mass to ensure internal comfort. So the occupant enjoys a more rapid response to heating than heavier forms of construction, whilst ensuring the internal temperature is better regulated by reducing the risk of overheating in hotter weather and rapid cooling at night

BUILD FOR PERFORMANCE… • Thermal performance: Heat loss through breaks in insulation reduced by up to 80% • Structural performance: Almost 3x stronger than traditional cavity wall construction when built using thin joint mortar • Fire performance: 4 hours fire resistance versus 30 minutes for timber frame and 2 hours for traditional cavity wall construction • Enhanced weather tightness, improving energy efficiency, eliminating drafts and improving durability • Zero condensation risk, eliminating damp and mould

BUILD FOR THE FUTURE… The homeowner can enjoy lifelong comfort and savings • SIMS’ superior structural and thermal performance results in a home which is a long-term investment for any new homeowner • The combination of high-performance construction elements ensures SIMS houses can easily meet and exceed stringent regulatory requirements, such as nZEB, which focus on the long-term energy efficiency of the dwelling. It is a construction method which makes it easy to go beyond current standards to achieve passive house, energy neutral, or even passive house plus building standards. • Enjoy a more sustainable home, with reduced environmental impact thanks to the lower energy consumption and carbon emissions.

The benefits are clear. Now it’s time to find out more. Talk to us about using SIMS by Quinn in your next project. Call: +44 (0)28 6774 8866 or Email: technical@quinn-buildingproducts.com ph+ | south dublin case study | 27

ENERPHIT

CASE STUDY

ENERGY BILLS

€20

PER MONTH FOR SPACE HEATING (estimate, see ‘In detail’ for more)

Building: 265 m2 deep retrofit of 1950s detached house Site & location: Linaro Avenue, Magazine Road, Cork City Standard: Enerphit certification pending

44 | passivehouseplus.ie | issue 35

CASE STUDY

ENERPHIT

SPECULATIVE E FFORT

EXTRAORDINARY A1 CORK UPGRADE IS IRELAND’S FIRST DEVELOPER LED ENERPHIT

ph+ | enerphit case study | 45

ENERPHIT

CASE STUDY

f you’re a developer with a high-end fixer-upper property to work on, not so long ago you might have spent your money just commissioning the necessary structural repair work, fitting new windows and maybe a new heating system, and doing a decent cosmetic job inside and out before selling it on for a reasonable profit. However, buyers looking for a walk-in property at the upper end of the market today do expect a bit more in terms of eco-cred, including a BER rating in one of the three A bands. After all, you might well boast about your newly renovated home’s luxury and beauty, but if you can’t brag about the fact that you rarely need to turn on the heating or that you generate surplus electricity from your PV panels, then you might feel like you’re missing out a little bit. Some developers are responding to changing demands and expectations when it comes to comfort and energy performance, but this house on Linaro Avenue in Cork city represents one of the most comprehensive energy retrofits in Ireland to date. Recently put on the market for €1.25 million, this circa 1950s five-bedroom home has been rebuilt to the Enerphit standard – the passive house benchmark for retrofit projects — along with a two-storey side extension and a single-storey rear extension. It’s one of only a handful of Enerphit certified homes in Ireland, but it’s the first to be done with a view to selling. “There might be a good reason for that, because they tend to be labours of love,” says developer David Lane of Lough Contractors. Lane had learnt all about energy efficient technology and construction methods through a course he did in the Cork Institute of Technology (CIT) back in 2011, which was followed shortly after by a CIT-hosted two-week trip to Germany to have a look at what was happening there in terms of energy efficient building. He then studied to become a certified passive house consultant in 2012. So, the idea of building to the Enerphit standard emerged back in 2016 when his firm bought the house. The property was in fairly poor condition cosmetically, but structurally it was okay. “In many ways we feel that perhaps we should have knocked it, but it was a relatively substantial house with a really good aspect and an interesting enough layout within that we felt we could develop,” says Lane.

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With solid block walls, no insulation, no cavity, and three large chimney shots, “it almost cried out to have this retrofit action put upon it, because it was so obviously not built with any thermodynamics in mind,” he says. With a plan to undertake the project in the downtime between other jobs and thereby give himself at least a couple of years to finish it, Lane drafted in passive house designer Paul McNally of the Passivhaus Architecture Company as part of a team that included architect Paul Hudson, engineer Declan Daly of Concept Design, and interior and garden designer Keith Spillane. McNally is one of Ireland’s longest-serving passive house designers, with a track record stretching back to the early noughties, including on one other Enerphit project. He is full of praise for the decision to retain the original building rather than knock it and displace the embodied energy, although

Applying external insulation to a 1950s home with a painted wet dash finish was hard work.

Photography: Jed Niezgoda

he acknowledges that the additional cost of doing so versus what would have been spent on a new build means the financial advantages are not so cut and dried. When the design of the extensions was finalised and then given the PHPP modelling once-over, McNally reports that he didn’t have to recommend any onerous changes for the design to meet the Enerphit standard. “There wasn’t anything that had to be fundamentally changed,” he says. The main issue was looking at thermal bridging, particularly with the cantilever structure like bay windows. “That would have been just something that didn’t have to be redesigned, more that David just had to think very clearly about how he was going to address that as a detail from a construction point of view.” Two of the now superfluous chimney shots were demolished as part of the extension works, which were kept largely within the footprint of a (now demolished) separate student bedsit block, to create the renovated 265 square metre dwelling. “You would see the shame in just knocking and rebuilding it,” says Lane. “You can never rebuild; you can never get the character back… and this house does retain its character. In addition, all the old concrete floors, footpaths, kerbs, walls, chimney shafts and roof tiles that were stripped and demolished on site were crushed and used in the infill grading of the garden and driveway. Talking to Lane, it does sound like there were several challenges in terms of preparing the building fabric for the airtight-

ENERPHIT

ness and insulation upgrades that, while not unexpected, proved quite frustrating to deal with. As you’d expect, applying external insulation to the outside of a 1950s home with a painted wet dash finish of varying thicknesses was hard work, requiring a lot of “scrubbing, hacking and power washing” to get a clean even surface on which to apply the insulation. Not to mention the difficulty of ensuring that there were no air pockets between the wet dash and the original blockwork before the insulation was installed. “It was a more involved process than you would ever imagine,” he says. That sheer hard graft extended to the job of fitting airtightness membranes in behind the retained floor joists of the original house, which involved a bit of trial and error. Another challenge was that one new wall could not be fitted with external insulation due to its proximity to an existing boundary wall. The solution here was to shutter the space between the two walls with KORE EPS insulation, and then to pump-fill the shuttered void with polystyrene bead. The extension wall on this elevation was also built entirely from Roadstone Thermal Liteblock to improve its thermal performance too. There are a few high-tech features, such as electric access gates, CCTV, category six cabling, wi-fi boosters and remote control Velux rooflights with solar-powered electric motors and sensors that close the windows when rain is detected, but it’s not over-done,

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CASE STUDY

ENERPHIT

FLOORS IN PROGRESS

1 The ground floor features 75 mm Kingspan TF70 incorporating lagged water distribution; 2 overlaid with 125 mm Kingspan TF70, plus 25 mm thick Kingspan TF70 border insulation; 3 foam insulation around service penetrations; 4 installation of the underfloor heating network; 5 pouring the 100 mm fibre reinforced concrete; 6 using a concrete float to smooth the finished surface.

EXTERNAL ENVELOPE IN PROGRESS

1 Compacfoam and infill insulation to windows; 2 external insulation block being installed under a window cill; 3 window cill detail; 4 200 mm Kore EPS installed over drip tray; 5 external insulation detail to boundary wall at rear of building; 6 insulation being installed around Velux roof window.

ph+ | enerphit case study | 49

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CASE STUDY

and money has clearly been spent in all the right places. That includes some €200,000 on the groundworks, including a short run of limestone steps and a beautifully executed courtyard garden. Along with solar photovoltaic panels, and an MVHR system from ProAir, the house also features a heat-pump powered, nine-zone heating system with underfloor heating throughout the ground floor, heated towel rails in all the bathrooms, and radiators in the first-floor bedrooms. It is tacitly acknowledged that this is probably a bit of an overkill for an Enerphit property, but Paul McNally points out that when designing a passive house for a high-end commercial market, it’s not surprising that Lane would specify something like this. He says that while a lot of clients understand that you can dial down the heating system to a small quantity of radiators or underfloor heating and still meet ambient comfort requirements in a passive house, others might want active heating all over, for what they perceive as greater uniformity or to have that nice, warm slab underfoot feeling. “It’s more about an aesthetic to physical comfort rather than a cold engineering calculation,” McNally says. “If you had a potential client that really liked the house and liked the location but who wasn’t au fait with passive house theory and practice, you don’t want to exclude those kinds of people because they might be thinking, ‘Well, will this house be warm if it’s a passive building, do I trust the science?’ So those kinds of people can still be a potential purchaser for this house because it’s not a bare-bones passive house in terms of comfort.” According to the property price register, Linaro House was bought in 2015 for €320,000. But despite the current £1.25m price tag, Lane says his profit margin won’t be massive due to the no-expense-spared approach, the aim of reaching Enerphit, the attention to detail and long project gestation. The house already attracted a firm offer shortly after it went on the market in July. Not surprisingly, Lane will be very sorry to see it go. “Although it might not have been a full-time project, it was certainly a kind of a full-time, ever-present, in-the-mind project,” he said. “It has occupied my head certainly for the last three and a half to four years and been hugely rewarding for such an emotional involvement.”

ENERPHIT

SELECTED PROJECT DETAILS Developer: Lough Contractors Architect: Hudson & Associates Civil & structural engineering: Concept Design Passive house consultant: The Passive House Architecture Company Main contractor: Lough Contractors Quantity surveyor: Synnott Scallan BER assessor: Start Energy Services Passive house certification: Earth Cycle Technologies Interior & garden design: Keith Spillane Mechanical contractor: Robert McGarry Plumbing & Heating Electrical contractor: Ger Callanan Electrical Airtightness tester/consultant: Air Matters External wall insulation: Kore, via HPS Group Thermal breaks: Compacfoam, via Partel Thermal blocks: Liteblock, via Roadstone Roof insulation: Rockprime, via HPS Group Additional roof insulation: Knauf, via

Brooks Floor insulation: Kingspan, via MD O’Shea & Sons Airtightness products: Siga, via Southwest Radon Airtightness products: Pro Clima, via Cork Builders Providers Liquid airtight membrane: Blowerproof Ireland Airtight mastic: Clean Energy Ireland Windows & doors: Viking, via West Building Products Roof windows: Velux Fit out: House of Coolmore Roofing membrane: Alkorplan, via CA Roofing Systems Roof tiles: Forticete, via Roadstone Limestone paving: Classic Driveways Planting: The Pavilion Garden Centre Heat pump & DHW tank: Daikin Towel rails: Irish International Trading Underfloor heating: Pipelife MVHR: ProAir Solar PV: PV Generation

WANT TO KNOW MORE? The digital version of this magazine includes access to exclusive galleries of architectural drawings. The digital magazine is available to subscribers on www.passive.ie

ph+ | enerphit case study | 51

ENERPHIT

CASE STUDY

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CASE STUDY

ENERPHIT

AIRTIGHTNESS IN PROGRESS

1 Solitex airtightness membrane behind strengthened joists; 2 airtightness plaster application on first floor; 3 wall service battening - concrete screw installation; 4 airtight tape and membrane at Velux window; 5 wall service battening and ceiling airtight membrane at main entrance; 6 airtight tape to window perimeters; 7 airtight plaster detail supplemented at reveals and cill with Blowerproof liquid airtight membrane; 8 heat recovery distribution to be connected to MVHR over utility room.

ROOF IN PROGRESS

It has been hugely rewarding for such an emotional involvement.

1 Inter rafter insulation on back roof; 2 & 3 soffit insulation detail.

ph+ | enerphit case study | 53

ENERPHIT

CASE STUDY

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CASE STUDY

ENERPHIT

IN DETAIL Building type: 265 m (238 m TFA) deep retrofit & extension of 1950s detached house. Two-storey side extension and single-storey rear extension.

Thermal Liteblock used in the deadwork of new wall build-ups. 220 mm collar of Xtratherm around two new Velux windows and around parapet of new flat roof.

Site & location: Linaro Avenue, Magazine Road, Cork City

EXISTING GROUND FLOOR Before: Uninsulated concrete floor. U Value: 0.5 W/m2K After: 804 hardcore fill, incorporating sewer runs, with limestone sand blinding under radon membrane. Followed above by 75 mm Kingspan TF70 incorporating lagged water distribution overlaid with 125 mm Kingspan TF70, plus 225 mm high, 25 mm thick Kingspan TF70 border insulation. 100 mm fibre reinforced concrete above, over 1000-gauge visqueen and underfloor heating network. U-value: 0.107 W/m2K

Budget: €750,000 (approx.) Completion date: December 2019 Enerphit certification: Pre-submission BER Before: F (401.26 kWh/m2/yr) After: A1 (21.52 kWh/m2/yr) Space heating demand (PHPP): 18 kWh/m2/yr Heat load (PHPP): 9.72 Primary energy renewable (PHPP): 38 kWh/m2/yr Primary energy non-renewable (PHPP): 67 kWh/m2/yr Heat loss form factor (PHPP): 3.58 Overheating (PHPP): 7% (if year above 25C) Number of occupants: Not yet occupied Energy performance coefficient (EPC): 0.155 Carbon performance coefficient (CPC): 0.144 Measured energy consumption: Not available Energy bills: Based on final energy demand figures in PHPP, and assuming 50% of the energy generated by the PV array is used in the building, the total annual energy bill would be €785 (including VAT, but excluding standing charges and levies, using the lowest available tariff available via Bonkers. ie.) The PV is estimated to reduce the bill by 20%. Applying this reduction evenly to each energy load, this results an estimated annual space heating cost of €242 (€20 per month) and domestic hot water cost of €194. AIRTIGHTNESS (at 50 Pascals) Before: Not tested After: 0.66 air changes per hour Thermal bridging: 75 mm deep Compacfoam blocks fitted under and alongside all window and doors to support and hold them inside the insulation envelope, subsequently dressed over with KORE EPS. Rafter fillet laid over rafters tapering from 220 mm at eaves to nothing approximately 2.5 m up each rafter, resulting in a 33-degree pitch bell-cast effect (40-degree pre-existing pitch) to reduce eaves thermal bridging. 135 mm Kingspan Kooltherm fitted between rafter fillets to run from plumb line of EWI to beyond full height of attic insulation. Roadstone

EXISTING WALLS Before: Painted external wet dash over block work of varying thicknesses and coated with sand, cement, skim coat and paint internally. After: Weber external primer and finish coats over 200 mm of KORE silver EPS insulation bonded with adhesive to avoid any thermal bypass, over existing wet dash render. Followed inside by blockwork of varying thicknesses. Sand and cement airtight render applied to interior with Blowerproof airtight sealant sprayed or brush painted to window reveals and some difficult pre-existing intersections. 35 mm battens fixed with concrete screws to form service cavities internally. 12.5 mm plasterboard slab and skim coat internally. U-value: 0.143 W/m2K NEW PITCHED ROOF Before: Concrete roof tiles on battens over bituminous felt, on cut roof pitched at 40 degrees. Glass fibre of 100 mm laid between ceiling joists over plasterboard and skim coat painted ceilings. After: Forticrete SL8 roof tiles by Roadstone over 35 mm counter battens, over 35 mm rafter aligned batten, over Kingspan Nilvent breather felt dressed vertically to maintain draft exclusion. 135 mm Kingspan Kooltherm fitted between rafter fillets to run from plumb line of EWI to beyond full height of attic insulation. Rockwool Rock Prime insulation blown into attic to fill in between 112 mm ceiling joists and over 100 mm x 75 mm wall plates to meet EPS eaves insulation blocks, and to underside of rafters and inter rafter insulation to a height of 600 mm. U-value: 0.077 W/m2K Extension floor: Concrete raft foundation with 804 hardcore fill, incorporating sewer runs, and limestone sand blinding under radon membrane. Followed above by 75 mm Kingspan TF70 insulation incorporating lagged water distribution overlaid with 125 mm Kingspan TF70 and 225 mm high, 25 mm Kingspan TF70 border insulation. 100 mm fibre reinforced concrete over 1000-gauge Visqueen and underfloor heating network. 0.107 W/m2K Extension walls: Weber external primer and

finish coats over 200 mm KORE silver EPS insulation bonded with adhesive to avoid any thermal bypass, on 225 mm block on flat and reinforced concrete heads with some steel lintels over Roadstone Thermal Liteblock 335 mm height deadwork, over min 110 mm height standard block deadwork. 35 mm battens fixed with concrete screws to form service cavities, 12.5 mm plasterboard slab and skim coat internally. U-value: 0.143 W/m2K Extension flat roof: Renolit Alkorplan PVC-P single ply roofing membrane, on 120 mm Xtratherm FR-ALU insulation over a further 100 mm Xtratherm FR-ALU, on Laydex torch on felt, on 18 mm Smartply OSB3. Followed inside by 225 mm x 44 mm joists supporting the OSB layer, cavity filled with Knauf Earthwool insulation, on SIGA Majpell membrane, on 35 mm battens oriented with the joists and at least 35 mm counter battens, on plasterboard and skim. U-value: 0.067 W/m2K WINDOWS & DOORS Before: Double glazed PVC windows and doors with overall approx U-value of 2.8-3.0 W/m2K New triple glazed windows: Viking SW14 aluminium clad triple glazed timber windows and doors with Swisspacer Ultimate and two low-e coating. Overall average U-Value of 0.77 W/m2K. Viking DK88 timber front door. Roof window: Velux passive house certified GGU 008230 with triple glazed outer glazing and double glazed inner glazing, thermally broken frame and solar powered operations including a rain sensor for automated closing. Passive House Institute certified installed overall U-value: 0.8 W/m2K HEATING SYSTEM Before: 15-year-old natural gas boiler with radiators throughout entire building. After: Daikin Altherma 7kW air-to-water monobloc heat pump with nine zone qual-pex underfloor heating system to ground floor with Fondital Lis-Cool towel rails throughout bathrooms and Milano Aruba radiators to first floor bedrooms. VENTILATION Before: No ventilation system. Reliant on infiltration, 3 x chimneys and opening of windows for air changes. After: ProAir PA 600LI Passive House Institute certified mechanical ventilation with heat recovery unit. Electricity: 19 m2 of PV panels giving 3.56 kW average annual output. Power directed to general household electrical use. The PV system & house electrical use are all monitored by an installed Smappee system which will learn how the electricity in the house is being used. If excess solar PV is generated the Smappee system for example can direct the homeowner to switch on the heat pump to top up the hot water tank. Allows for offsite control & monitoring.

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SCOTLAND

CASE STUDY

ENERGY BILLS

Â£35

PER MONTH AVERAGE BILL FOR ALL ENERGY Building: 137 m2 fully prefabricated timber frame dwelling Site: Strathpeffer village, Easter Ross Standard: Passive house classic

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CASE STUDY

SCOTLAND

STUDY

STORE

COVERED DECK

LIVING ROOM

SECTION

HIGHLAND WARRIOR STUDY

STORE

COVERED DECK

LIVING ROOM

SECTION

STORE

PLANT

SCOTTISH PASSIVE HOUSE BUILT WITH INNOVATIVE LOCAL TIMBER SYSTEM BATHROOM

STUDY

MASTER BED

STUDY

A beautifully detailed and rustic new passive house in the north of Scotland was built with a unique off-site construction system using local timber, and was created by a design-and-build firm that aims to put sustainability at the heart of everything it does. STORE

STORE

VOID

PLANT

BATHROOM

COVERED DECK

LIVING ROOM

STUDY

MASTER BED

VOID

SECTION

UPPER FLOOR PLAN

Words by John Cradden

UPPER FLOOR PLAN

STORE

PLANT WORKSHOP BATHROOM

WORKSHOP WOOD LOG STORAGE

STUDY

MASTER BED

WOOD LOG STORAGE

VOID

ENTRANCE DECK

UPPER FLOOR PLAN SHOWER UTILITY

PLANT

HALL

LIVING ROOM

ENTRANCE DECK

BEDROOM

KITCHEN

STORE

WORKSHOP

SHOWER

DINING UP

DECK

UTILITY

PLANT

WOOD LOG STORAGE

HALL

GROUND FLOOR PLAN BEDROOM

LIVING ROOM

KITCHEN

GEANAISEAN HOUSE STRATHPEFFER

ENTRANCE DECK

STORE

ph+ | scotland case study | 57 SHOWER

UTILITY

DINING

PLANT

HALL

DECK LIVING ROOM

BEDROOM

KITCHEN

SCOTLAND

CASE STUDY

If you’ve been out on a Scottish site in the middle of winter, you really begin to appreciate how important is to have a facility that is well lit and heated.

f you wanted to build a house to the passive house standard but with the strongest possible nod to sustainability, timber frame construction would probably rank high on the shortlist of build methods. But what if you were concerned about the sustainability and carbon footprint of imported timber? That’s the predicament that Tim Dawson of Strathpeffer in Scotland found himself in after receiving inheritance from his late father in 2015, enabling him to fulfil a dream of building a new home. After a long search, he had found a local site with full planning permission for the replacement of a derelict bungalow. It also came with planning permission in principle for a second dwelling, but he liked the site so much he bought it in 2018 with the firm intention of building only one house on it.

58 | passivehouseplus.ie | issue 35

His other firm intention was in relation to the brief for his new ‘forever’ home. He wanted a modest, two-bed dwelling with generous office space, a utility room and adjoining workshop, and built to fully certified passive house standard but with the lowest possible carbon footprint, and constructed with local timber. One of the two local architects that Tim consulted during his research was a unique design and build firm in Inverness called Makar. Tim felt that Makar founder Neil Sutherland was very much on his wavelength, despite the fact that the firm had never previously built a passive house (though they had designed a community centre in nearby Gairloch that is passive house certified). Tim was particularly impressed with the standard Makar system, an off-site,

timber-based panel system very similar to a SIPS (structurally insulated panel system). SIPS is essentially insulated timber panels assembled together, often without the need for separate structural elements, but a typical build-up is likely to have its fair share of synthetic materials like adhesives, timber preservatives and polyurethane foam insulation. But Makar describes its unique system as ‘n-SIPS’ because of its use of all natural materials, including untreated timber, Warmcel cellulose insulation (made of recycled newspaper) and wood fibre board (made from timber waste). The timber used for the frame is untreated Scottish-grown spruce, while Scottish-grown larch or Douglas fir is the choice for the cladding and post-and-beams. Although

CASE STUDY

SCOTLAND

their system didn’t initially meet the passive house standard, Sutherland and his architect colleague, Catriona Kinghorn, were keen to take up the challenge of designing and building a passive house as they felt confident it only needed minor amendments to meet the standard. But given its northerly highland location, it was necessary to achieve even more onerous U-values than normal for a UK passive house. Kinghorn had qualified as a passive house designer a year before she and Sutherland met Tim. “And, actually, at the time we met Tim,” recalls Kinghorn, “I was due to be away that summer in Japan and New England visiting other passive house designers — I had a travel grant awarded by the Winston Churchill Memorial Trust — so this was always on our mind. And I guess Tim really appeared at a very fortuitous moment for the company, because it was a real meeting of minds. “Tim’s brief was very clear. It was a really well written brief. He didn’t try to design the house itself, but he was clear on what he wanted and he didn’t want. And he really understood passive house principles; he’d made the effort, he had the technical understanding of passive house to understand why it was supported and he’d made that decision. He wanted to reach that standard.” The site also lent itself well to passive house design, as it was well orientated with a good southerly aspect, slightly sloping downhill, with deciduous trees to the east and an area of high ground to the west — perfect for low sun shading. It’s clear that part of the meeting of minds that Kinghorn describes is Tim’s attraction to the Makar commitment to deliver buildings that are healthy and sustainable, while also attaining his prized goal of a certified passive house. “Passive house is an energy-balance calculation, with no comment on how the energy balance is achieved,” says Kinghorn. “We would not have been comfortable delivering a passive house project relying solely on materials we felt are harmful to the user or the environment.” The solution was the Makar standard Warmcel-insulated timber frame but boosted with a 180 mm (compared to the normal 60 to 80 mm) outer layer of tongue-andgroove wood fibre insulation board. Careful detailing at junctions ensured a continuous insulation jacket. The result is a ‘breathing’ wall construction, which allows moisture vapour to dissipate naturally through the wall. All timber is untreated, while an 18 mm OSB board was used as an internal airtight layer, and taped at all junctions. “We worked really hard to reduce the timber content of the panels as much as possible [to allow more space for insulation], and to develop standard off-site panel joints that maintain the thermal envelope,” says Kinghorn. She adds that they plan eventually to use Scottish-timber-produced wood

Photography: Catriona Kinghorn / Makar

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SCOTLAND

CASE STUDY

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CASE STUDY

SCOTLAND

CONSTRUCTION IN PROGRESS

The Makar prefabricated timber frame system being built in their workshop, showing 1 the frame, 2 the postbase, 3 the roof panel, and 4 the cladding; 5 & 6 assembly of the frame on-site; 7 the panels are built complete with insulation, doors, windows, roof and cladding; 8 18 mm OSB board was used as an internal airtight layer, and taped at all junctions; 9 the walls are finished inside with plasterboard enclosing a woodfibre-insulated service cavity.

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SCOTLAND

CASE STUDY

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CASE STUDY

SCOTLAND

The final result is a lovely, understated home that really blends well into its environment.

fibre products in order to reduce reliance on insulation materials imported from abroad. Interestingly, all Makar-built houses today are specified with MVHR (mechanical ventilation with heat recovery) but Kinghorn points out that even 10 to 15 years ago the build-up of moisture was far less of an issue with its breathable walls than other modern build methods. “Once you get to a certain level of airtightness, like passive level airtightness, you do need the MVHR ventilation,” she says. “So that goes into all of our houses as standard anyway.” Underlying Makar’s commitment to a wide-ranging sustainable rural economy in the Highlands is that as well as tying in interests in forestry, regeneration, timber use and healthy construction and design, Neil Sutherland’s family also run an organic farm on the same site as the company’s factory. Needless to say, being able to build its wall panels off-site conferred several advantages in meeting the challenge of building Tim’s passive house, not least a high degree of quality control. “Our drive is to do things off-site as much as possible, simply because when you’ve been out on a Scottish site in the middle of winter, you really begin to appreciate how important is to have a facility that is well lit and heated, and everyone’s working on benches, tables and the panels are laid horizontal.” Kinghorn also appreciates the convenience of working right next door to the factory. “As a designer, especially as a passive house designer, working literally yards away from the person building wall panels means you can literally come out and talk through problems, solve them there and then and you don’t need to wait a week while someone gets out to the site.” The panels, which are built complete with insulation, doors, windows, roof and cladding, are typically 2.4 to three metres wide by 4.8 metres high, and weighing one to 1.5 tonnes. House superstructures are assembled on site by a small team using a 40 or 55 tonne crane, and are usually made wind and watertight in less than a week – another advantage when building in remote rural locations. In a bid to keep its use of concrete to a minimum, the company also usually specifies pier foundations on three-metre

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SCOTLAND

CASE STUDY

grids to support the four panels that make up a typical house. At the time however, the team decided to go with an insulated concrete slab for Tim’s house because they were unsure if their pier foundation would meet passive house criteria, leading to a “slight disappointment for us and for Tim”, says Kinghorn. “Looking back, we were maybe a little over-cautious as it was our first passive house build.” The final result is a lovely, understated home that really blends well into its environment, while on the inside, there is a real character to the rooms, from Tim’s study / music room, to the roof-lit mezzanine level that brings light down to the dining area through a slatted timber screen. “It really feels like a home, says Kinghorn. “I think we responded to Tim’s brief well — creating that strong link to the outdoors, and playing with height and light to make some areas cosier while other areas feel bigger and higher.” “A really important part of the brief was a connection to the outdoors and the garden from inside, with sheltered outside space — commonly referred to as ‘sitooteries’,” added Kinghorn. Although the house requires very little by way of space heating, Tim chose to install a wood burning boiler stove, which supplies hot water to two radiators as well as domestic hot water. The hot water is also supplemented by solar thermal panels and PV panels (the PVs are linked to an immersion heater, mostly used in the summer months). A rainwater harvesting system supplies water to the WCs, washing machine and garden, while an electric car charging point is located by the main door. Tim has been living in the house since September 2019, and is delighted. “Where do I start? The house fits beautifully into the landscape. Everyone bar none has said that they like the look of the house. Its energy efficiency is looking promising in these early days. It responds very well to the weather and is warm in the winter and pleasantly cool in the summer. It’s easy to live in and to keep clean.” He reports that since his smart meter was installed in February this year, he has used 684 kW of electricty from the grid and exported 2,106 kW. “The house is roughly twice the floor area of my old one yet the running costs are around a third compared with previously. Once I start to receive the export tariff the costs may reduce again.” Kinghorn describes Tim’s house as a labour of love. It may have taken more than a year from start to finish, but the result is a passive house system that can be easily replicated, and likely to take less time to build for future clients. Furthermore, the firm won two awards for it from the Alliance for Sustainable Building Products in the Best New Build and Best Product categories. “Now we have a passive-compliant off-site system that we can replicate time and time again,” she says.

64 | passivehouseplus.ie | issue 35

WANT TO KNOW MORE? The digital version of this magazine includes access to exclusive galleries of architectural drawings. The digital magazine is available to subscribers on www.passive.ie

SELECTED PROJECT DETAILS Client: Tim Dawson Architect: Makar Civil & structural engineer: SF Structures Build system: Makar Contractor & project management: Makar Passive House certifier: Passivhusbyrån Ingo Theoboldt Electrical contractor: ICM Electrics Airtightness tester/ MVHR installer: Airtight Build Airtightness tapes: Siga Windows & doors: Internorm by Scotia Cellulose insulation: Warmcel, via PYC Group Wood fibre insulation: NBT / Soprema Floor insulation: Quinn Building Products / Kingspan Thermal blocks: Forterra Roof lights: Fakro, via Caley Timber Boiler stove, thermal store & solar thermal: Ashburn Stoves Solar PV: AES Solar Heat recovery ventilation: Paul, via Airtight Build Rainwater harvesting: Rainwater Harvesting Ltd Kitchen: Howdens Larch cladding: BSW Flooring: Russwood Roofing: Nu-Style Products Drainage design: Caintech Ltd

CASE STUDY

SCOTLAND

IN DETAIL Building type: 137 m2 (treated floor area) 1.5 storey 3-bedroom detached house built w/ prefabricated timber system.

used 684 kW of grid electricity. House electricity consumption includes electric car charging.

Site & location: Strathpeffer, Easter Ross, Highlands. Built in garden of a derelict bungalow on the outskirts of the village.

Thermal bridging: Thermal bridging was largely avoided through the use of an external 180 mm wrapped wood-fibre board insulation. All bridges were calculated using Therm software, and checked by the PH certifier. Ambient thermal bridges: 159m at 0.003 W/mK. Perimeter thermal bridges: 48m at 0.007 W/mK

Completion date: September 2019 Budget: £365,000 ‘turn-key’ construction cost Passive house certification: Passive House Classic certified Space heating demand (PHPP): 15 kWh/m2/yr Heat load (PHPP): 12 W/m2 Primary energy non-renewable (PHPP): 62 kWh/m2/yr Primary energy renewable (PHPP): 145 kWh/m2/yr Renewable energy generation (PHPP): 69 kWh/m2/yr (relative to building footprint) Heat loss form factor (PHPP): 2.62 Overheating (PHPP): 0% of hours above 25C Number of occupants: 1 Airtightness (at 50 Pascals): 0.34 ACH Energy performance certificate (EPC): A 115 Measured energy consumption: From October 2019 to July 2020 inclusive (10 months), the house consumed 2,973 kWh of grid electricity. Over the same time period the solar PV array generated 4,324 kWh. A smart meter was installed in February 2020, and from then until July 2020 inclusive the house exported 2,106 kWh of solar electricity, consumed 1,618 kWh of solar generated electricity, and

Energy bills (measured or estimated): Tim Dawson’s electricity bill averages to £35 a month for grid electricity, which includes some hot water generation but no space heating. He does not receive a feed-in-tariff for exported electricity. All wood used so far for the wood burning boiler stove has been from site offcuts. Ground floor: Hardwood floor finish on 45 mm battened service zone, on 125 mm reinforced concrete slab, on slip membrane, on 300 mm Quinn Therm ground floor insulation, on 1200 g DPM, on 150 mm sand blinded hardcore. Perimeter load bearing Thermalite Aircrete Trenchblock insulated externally with NBT plinth board. U-value: 0.071 W/m2k Walls: 150x25 mm vertical board-on-board heartwood larch cladding on 38x50 mm horizontal battens, on 25x50 mm vertical battens, on prefabricated wall panel comprising: 180 mm Pavatex Isolair insulation board on C16 kiln-dried regularised untreated 245 mm studs with cellulose insulation, with 18 mm OSB 3 internal lining board as airtight layer taped at all junctions. Internally there is a 45 mm battened service zone insulated with Pavaflex wood fibre insulation, finished with 12.5 mm plasterboard, taped and filled. U-value: 0.091 W/m2k Roof: Anthracite grey big six profile metal roofing on 50x50 mm battens, on 120x50 mm Douglas fir secondary rafters screwed

to prefabricated roof panel comprising: Roofshield membrane on 180 mm Isolair wood fibre insulation, on 245 mm C16 kiln-dried regularised untreated rafters with cellulose insulation, lined internally with 18 mm OSB 3 airtight layer, all junctions taped. 45 mm internal service zone insulated with Pavaflex wood-fibre batts. 12.5 mm plasterboard internally, taped and filled. U-value: 0.090 W/m2k Windows: Internorm HF310 aluminium/timber composite triple glazed windows. Average installed U value average: U-value: 0.8 W/m2k Roof windows: Fakro FTT U8 Thermo triple glazed roof windows. Average installed U-value: 0.94 W/m2k Heating system: Verner 13/10.2 wood burning boiler stove linked to large thermal store feeding 2 x radiators and 2 x towel rails. The thermal store is also fed by the solar thermal panels and is topped up by immersion via the PV electric panels. The solar thermal array generated 2,000 kWh of energy between November 2019 and July 2020 inclusive. Ventilation: Paul Novus 300, Passive House Institute certified to effective heat recovery efficiency 93%. Water: A rainwater harvesting system is installed, which supplies both WCs, the washing machine and garden taps. Electricity: 6.87 kW solar PV array. Once the thermal store is up to temperature the PV panels automatically divert to the electric car charging point. See ‘measured energy consumption’ above for PV kWh generated & exported. Green materials: Dwelling uses natural materials in an off-site system that can be easily reproduced to meet the PH standard. Local timber for wall panels and cladding, wood fibre and cellulose insulation.

ph+ | scotland case study | 65

HILL HOUSE

CASE STUDY

ENERGY BILLS

£21

PER MONTH FOR SPACE HEATING (estimate, see ‘In detail’ for more)

Building: 119 m2 detached passive house Build method: Structural insulated panels (SIPs) Site & location: Semi-rural site, Lewes, East Sussex Standard: Passive house classic certified

PECKING

ORDER

AWARD-WINNING PASSIVE HOUSE MAKES AN ELEGANT MARK ON THE SOUTH DOWNS Despite the challenges of getting planning permission within a national park, a new passive house on a hillside in the South Downs managed to woo the planners with a sympathetic, discerning design inspired by a surprising source — two dilapidated old chicken sheds. Words by David W Smith

66 | passivehouseplus.ie | issue 35

CASE STUDY

His imagination was fired by a pair of disused chicken sheds.

he architect Charles Meloy – who has built the first passive house in the Sussex Downs National Park (SDNP) – dreamed for “decades” of building an affordable, sustainable house in this beautiful landscape. But not only was it prohibitively expensive, there were also restrictions on the types of developments allowed. Active searches for a suitable, economical plot proved futile. Then, one day back in 2013, Charles was relaxing on a walk across the Sussex Downs with a friend when his imagination was fired by a pair of disused chicken sheds a few minutes’ walk from Lewes. “We used to do a walk on an ancient drove road used by fisher folk to carry fresh fish from Brighton to the county town of Lewes. I wouldn’t be much of a developer as it was actually the third time I’d walked past the site before I noticed two dilapidated chicken sheds in a garden,” he says. “It suddenly struck me that we could build a house on the land and design it in a way that carried echoes of the original sheds.” Charles quickly entered into a conversation with the owner who used the sheds for storage. He struck up a provisional verbal agreement to buy the land that was later formalised. The sale for a pre-determined price was conditional on Charles receiving planning permission on the site, which is outside of the Lewes town boundary but within the national park.

HILL HOUSE

Despite this challenge, Charles was confident of getting planning permission when he filled in his application in 2014. “We had a lot of things going for us. The use of the land was residential as we were effectively building on a section of their garden. Another plus was that the existing buildings were still there, and they were dilapidated, so we could prove that a new structure would lead to an ‘enhancement and promotion’ of the use of the national park, which is one of the key criteria for planning. We placed Sussex bullock hedging right along the roadside to blend into the surrounding landscape and we used untreated western red cedar that weathers over time and blends in beautifully with the surrounding woodlands,” he says. Charles took care to get all his future neighbours on side. He met the owners of the three houses that are adjacent to the site and explained his plans. Everyone reacted enthusiastically. Charles then showed his design to the local conservation group Friends of Lewes, who were equally supportive. “I think when you prepare a planning application, it’s about being neighbourly and polite. If you don’t take the time to explain everything to all the stakeholders, the danger is that when they get the planning letter, it comes as a shock. An unexpected planning letter can land as heavy as a lump of lead when it comes through their door.” A lot of the support was inspired by his

ph+ | hill house case study | 67

HILL HOUSE

CASE STUDY

(above) The passive house certified Hill House, with the dilapidated chicken sheds that were originally on the site (inset).

elegant and sympathetic design. The essence of his concept was that the two new singlestorey buildings would carry a memory of the original chicken sheds. The two sheds had covered an area of 100 m2, whereas the completed house, which also utilises the gap between the sheds, is 125 m2. Charles was fortunate in that the original L-shaped layout, although not ideal from a heat loss perspective due to the large surface area, allowed for the living and sleeping areas to be split, with the open plan living area having a southerly aspect to benefit from solar gain in winter. The first shed was replaced with an open-plan space with living room and kitchen. Meanwhile, the second ‘shed’ with the bedrooms was fitted with east-facing windows that provide morning light.

68 | passivehouseplus.ie | issue 35

In between, Charles designed a linking section for the service core, “We didn’t have to fight the existing form one bit. Open plan areas can be sprawling, but the detachment of the two sections gave us some definition,” he says. Charles was committed to building a passive house, but not at the cost of the aesthetics. He was adamant that the architectural design had to come first. “That might not be music to some passive house designers, but it was an attempt to see if there really were any restrictions implied by the design when aiming for [the passive house standard]. If there were, they had to be integrated into a coherent piece of architecture,” he says. Prioritising the architecture set additional challenges for the passive house consultant

Everything has been designed exactly as we want, and everything works as planned.

CASE STUDY

HILL HOUSE

Dan Gibbons, founder of Ape Architecture & Design in London. Charles and Dan have known each other since they shared a flat as students of architecture in Edinburgh and have a good rapport. “It was satisfying working with Charles from an architectural point of view. With a lot of passive houses I’ve worked in, the project has been driven by what makes sense for PHPP [the passive house design software], whereas Charles emphasised the design. It meant I had to up my game to come up with solutions to offset some of the more compromised areas,” Dan says. “And it stands up as a very architectural passive house, whereas a lot of them can look a bit lumpen and unfinessed. More often than not it becomes more about the best performance quality than whether it looks good.” One complicating factor was that Charles wanted to express the ground floor slab on the outside of the building for aesthetic reasons, whereas a more common method for a passive house would be to insulate the ground slab externally. “It made it harder to achieve [the passive standard], but for Charles it was a line in the sand,” Dan says. “We had a lot of discussions and spent a lot of time going back and forth working out the details. We had to work around having an exposed structural slab on the side of the building, then an insulated screed internally, while making sure we could still get the structural connection between the slab and the SIP (structural insulated panel) frame without there being a detrimental thermal bridge. But we managed it and it meant we got a very clear line aesthetically on the outside of building where you can see the concrete slab before

Photography: Charles Meloy

ph+ | hill house case study | 69

HILL HOUSE

CASE STUDY

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CASE STUDY

HILL HOUSE

Charles wanted to express the ground floor slab on the outside of the building.

the timber starts.” Dan recalled having “lots of amusing discussions” about the window designs. “Charles initially wanted to finish off the timber frames at the window reveals which relied on some large pieces of aluminium framing,” he says.” But this would have created a large thermal bridge that sucked heat out of the building. “We had to do some careful modelling to make sure the aluminium was not directly connected to the windows. We also had lots of discussions about the window suppliers as when we were running the PHPP numbers and considering the windows Charles wanted, we always had to take into account his budget. After a few alterations, we eventually found a supplier with the performance we needed for the price he was willing to pay.” Budgetary considerations were behind Charles’ decision to use SIP panels for the frame. SIPs are essentially a ‘sandwich’ of insulation, often polyurethane foam but in

this case EPS, between two structural boards like OSB. Charles wanted the structure above ground to be lightweight to offset all the heavy elements touching the ground, including the concrete internal flooring and the exposed concrete at the base outside. Timber frame was considered, but the SIP option was more economical and the suppliers were able to install them quickly. For Dan, it was the first time he had worked on a passive house using SIP frames. “My preference would still be for timber frame with natural insulation, but the SIP panels made it easy to achieve the blanket U-values we needed from the walls by insulating correctly,” he says. To manage costs, Charles took charge of almost the entire build. He continued to work four days a week for his Brightonbased practice Meloy Architects, but in the evenings, he drove down to the site and often didn’t stop work until midnight. The fifth day of each working week was devoted to his self-build, as was one day every

weekend. At times, he was helped out by a friend he had met years earlier on a bus trip in Australia, and who was training to be a teacher in Lewes. Together, they installed all the insulation in the floor and added the cladding on the outside of the house. They also did the stud work, took care of the plaster boarding and fitted the internal doors. “It was tiring, but I had no option but to keep going until I’d finished. I worked out we used 10,000 screws for the cladding outside. But you actually get pretty efficient after you’ve done 1,000 or so!” Charles employed sub-contractors for specialist jobs, such as the groundwork, fitting the SIP frame, the windows and the concrete flooring. Sub-contractors also helped out with the bathroom and the cabinetry. “The build went smoothly. It was the opposite of one of those Grand Design style TV programmes where everything keeps going wrong!” With Charles doing most of the work a huge

ph+ | hill house case study | 71

HILL HOUSE

CASE STUDY

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CASE STUDY

HILL HOUSE

CONSTRUCTION IN PROGRESS

1 The ground floor concrete slab was left exposed on the outside of the building for aesthetic reasons; 2 erection of the SIPS frame underway; 3 210 mm Xtratherm Thin-R insulation covers the floor; 4 laid on top of this is a 110 mm screed; 5 Intello airtightness membranes and taping on walls and pitched roof; 6 this is followed inside by more Xtratherm Thin-R insulation on walls and roof, and then 25 mm timber studs forming services cavity on walls; 7 after that, there is further layer of OSB inside; 8 architect Charles Meloy with his wife Hannah and their children on the site; 9 Western red cedar external cladding on walls and roof.

ph+ | hill house case study | 73

HILL HOUSE

CASE STUDY

amount of money was saved, and Hill House cost a very reasonable £250,000 to construct (not including the cost of the land). Last year, it won four separate RIBA awards — in the south east, sustainability and small project categories, as well as a national award. Despite the focus on design, the passive house standard was achieved comfortably, and the building offers exceptional thermal performance and airtightness. Hot water is generated with an air source heat pump and extra space heating can be provided through a sealed wood burning stove. Charles lives with his wife and three small children at the property, which is near to the village of Kingston and a 10-minute walk into Lewes. Sat on the top of a breezy hill which was once home to Lewes’ windmills, it’s in the countryside, but near schools and amenities. “It’s a huge change from the very tall, tight townhouse we had before in Brighton, and we love it. Everything has been designed exactly as we want, and everything works as planned,” he says.

SELECTED PROJECT DETAILS Architect: Meloy Architects Passive house consultant: Ape Architecture & Design Mechanical and electrical consultant: Alan Clarke Structural consultant: Reaction Engineers Passive house certification: MEAD Consulting Planning consultant: Pro Planning Arboriculturalist / ecologist: PJC Consultancy Daylighting assessment: DeltaGreen Foundations: SMD Formwork Steelwork: South Coast Steel Windows and doors: Doorstop Southwest Ltd Roof lights: Solar Vision Ltd MVHR: Systemair Heat pump: Ariston Airtightness testing: Tophouse Assessments Build system: SIPS Eco Additional wall & roof insulation: Xtratherm Thermal breaks: Armadillo Plates Airtightness products: Ecomerchant & Ty-Mawr Lime Ltd Underfloor heating: Heat Mat, via BTR Tech External blinds: Hella Roofing: DMB Flat Roofing Ltd Electrical: John Wadham Plastering: Rafferty (Plasterers) Ltd Landscaping: Worman Construction Ironmongery / doors: Aspex Concrete flooring: Steysons Granolithic Cedar cladding: Wenban Smith Sanitaryware: CP Hart Wood-burning stove: Westfire LED Lighting: Lightfoot LED Permeable paving: Tuff Turf Wastewater treatment system: Klargester Biodisc Cabinetry / kitchen: JM Furniture

74 | passivehouseplus.ie | issue 35

WANT TO KNOW MORE? The digital version of this magazine includes access to exclusive galleries of architectural drawings. The digital magazine is available to subscribers on www.passive.ie

CASE STUDY

HILL HOUSE

IN DETAIL Building type: 120 m2 SIPs passive house  Location: Lewes, East Sussex Completion date: Jan 2017 Budget: £250,000 Passive house certification: Passive house classic certified Space heating demand (PHPP): 13 kWh/m2/yr Heat load (PHPP): 12 W/m2 Primary energy demand (PHPP): 110 kWh/m2/yr Primary energy renewable (PHPP): 51 kWh/m2/yr Hot water demand (PHPP): 17.2 kWh/m2/yr Heat loss form factor (PHPP): 4.38 Overheating (PHPP): 0% of year above 25C Number of occupants: 4 Airtightness (at 50 Pascals): 0.6 air changes per hour Energy performance certificate (EPC): B 89 Thermal bridging: Critical thermal bridges, slab edges, steel beams, window frames

etc were modelled in Therm – establishing an average Psi value of 0.012. All remaining thermal bridges were left as the PHPP default of 0.01 even though sample modelling of the standard SIPs details suggested that lower Psi values were being achieved. Energy bills (measured or estimated): Based on final energy demand figures in PHPP, USwitch.com suggests a lowest available annual space heating bill of £248, or £20.66 per month, and hot water bill of £259, or £21.58 per month. Figures include VAT but not standing charges. Space heating figures do not include the wood burning stove, for which all wood so far has come from the site. Ground floor: 110 mm screed over 210 mm Xtratherm Thin-R insulation over 200 mm concrete slab. U-value: 0.101 W/m2K Walls: Western red cedar external cladding on battens and counter battens, followed inside by Tyvek UV Facade breather membrane, structural insulated panel comprising 172 mm SIPS Eco EPS insulation sandwiched between 11 mm OSB boards, Intello air tightness membrane, 60 mm Xtratherm Thin-R insulation, 25 mm timber studs forming services cavity, 11 mm OSB, plasterboard. U-value: 0.108 W/m2K. Pitched roof: Western red cedar external cladding on battens and counter battens, followed inside by roof deck, Tyvek UV Facade breather membrane, SIPS Eco Structural insulated panel comprising 172 mm

EPS insulation sandwiched between 11 mm OSB boards, Intello air tightness membrane, 80 mm Xtratherm Thin-R, plasterboard. U-value: 0.108 W/m2K. Flat roof: Single ply membrane, followed beneath by 18 mm plywood to falls, 120 mm Xtratherm Thin-R, 18 mm plywood, 50 mm Xtratherm Thin-R between joists, ventilated cavity followed underneath Intello air tightness membrane, plasterboard. U-value: 0.123 W/m2K. Windows & external doors: HON Quadrant Studio FB IV-9 timber-aluminium windows and doors. Typical spec: 44 mm triple glazing with Saint-Gobain ClimaPlus Ultra N glass & a Swiss spacer bar. Ug value: 0.50 W/m2K, dB value: 34, average overall U-Value: 0.80 W/m2K. Roof windows: Vitral 4-degree Skyvision Comfort triple glazed Ecoline openable rooflights & Vitral 4 Skyvision Ecoline frame-only fixed rooflights. Ecoline glass, 32 mm low-e, krypton fill. Ug = 0.7 W/m²K. Heating system: Ariston Nuos 250i heat pump for domestic hot water and also supplying duct heater in MVHR system, plus underfloor heating if needed in extreme weather. Westfire 35 standalone wood burning stove. Ventilation: Systemair VTC 200 MVHR system. Passive House Institute certified heat recovery rate of 90%.

ph+ | hill house case study | 75

INSIGHT

RADON

IN PASSIVE HOUSES Radon is one of the most dangerous indoor air pollutants, yet there is little research on how it is affected by different forms of construction and ventilation. A new study, however, suggests that homes built to the passive house standard are significantly less at risk of radon build-up.

Words by Kate de Selincourt

10 9 8

CASE STUDIES

7 6 5 4 3 2 1 0

100

200

300

400

500

RADON LEVEL - Bq/m

Passive House Standard Homes

1 18 51

2 43 52

3 23 34

4 26 48

5 72 144

600

700

800

6 37 126

7 20 58

8 67 598

9 166 409

10 37 104

Direct comparison of radon levels in individual passive houses versus standard homes in the immediate vicinity.

ew research comparing radon levels in passive and non-passive homes suggests that passive house construction protects occupants from excessive radon levels. Across Ireland, around one in 12 homes exceeds the level of 200 Bq/m3 (becquerels per cubic metre of air) above which remedial action is recommended. In a survey of 77 certified passive homes in the Republic of Ireland, and 20 in the UK and Northern Ireland, none exceeded this level. The average radon level in the passive homes was less than half the average found in a sample of non-passive homes at the same locations. New build passive houses had the

76 | passivehouseplus.ie | issue 35

lowest radon levels, but the small subset of five Enerphit (passive retrofit) projects also had radon levels lower than non-passive homes. The research was led by Barry McCarron of South West College, Enniskillen, and supervised by Dr Xianhai Meng and Professor Michael McGarry of Queens University Belfast. South West College has a particular interest in passive house performance. It is a leading centre of passive house training in Ireland, with its own passive house certified teaching and research space, the CREST centre. In Ireland and the UK, radon is the leading cause of lung cancer after smoking, and is recognised as an important indoor pollutant

by both governments. It is a colourless, odourless and tasteless gas emitted from rocks and soil that can enter buildings through cracks and gaps, and accumulate to potentially dangerous levels. In Ireland, it is estimated that radon exposure accounts for approximately 14% of all lung cancers â&#x20AC;&#x201C; equating to around 300 cases per year. In the UK around 1,100 deaths from lung cancer each year are related to radon in the home. Yet as Barry McCarron found, there is very little research anywhere looking at the impact of construction methods, as opposed to the impact of location, on building radon levels. The National Radon Control Strategy

INSIGHT

in Ireland notes that “the relationship, if any, between increased airtightness and elevated radon levels is unknown”. There has been speculation that airtight dwellings might be at risk of a build-up of radon. Passive house ventilation is known to deliver excellent indoor air quality, on metrics such as relative humidity and carbon dioxide . But nonetheless Barry McCarron found that even some of his architecture school colleagues assumed that passive houses would be at higher risk from radon due to their airtightness. “When I was planning this research, I would get that typical question – oh, passive house couldn’t possibly be good for radon, could it?” he recalls. Less radon in passive houses Of the 97 certified passive houses studied, 92 were new build, and five were Enerphit retrofits. Comparison homes in the immediate vicinity were found for 25 of the passive homes — these were of a similar size but of non-passive construction. Radon monitoring showed the certified passive house dwellings performed a lot better in respect of indoor radon concentrations than the comparison dwellings, and compared to Irish homes as a whole. The average level in passive homes was 36 Bq/ m3, compared to the level in the comparison homes, which averaged 88 Bq/m3. The national average level in Ireland is 77 Bq/m3. The Irish and UK governments have both set an ‘action level’ of radon gas concentration of 200 Bq/m3, above which remedial action to reduce indoor radon concentration should be

taken. In the UK there is also a ‘reference level’ of 100 Bq/m3, which according to the public health authorities, all homes should aim to be below. None of the 97 passive house certified homes (new build and Enerphit) exceeded the action level of 200 Bq/m3, while two of the 25 comparison homes (8%) did so. All but 7% of the passive homes were also below the lower ‘reference’ level of 100 Bq/m3, while 16% of the comparison homes exceeded this. In Ireland as a whole, an estimated 25% of homes are above 100 Bq/m3. What about retrofit? The average radon level in the five Enerphit homes was 72 Bq/m3, not as low as the new build passive homes, but still lower than the national average, and below the 100 Bq/m3 reference level. There were 10 matched pairs of homes located in designated high radon risk areas. Only one of the certified homes there (an Enerphit retrofit) exceeded 100 Bq/m3, with a recording of around 150 Bq/m3. However, the identical but non-retrofitted home next door had one of the highest radon levels measured in the survey, at over 400 Bq/ m3. Although the numbers were too small to enable predictions about the radon performance of certified passive house retrofit more generally, these early results are encouraging signs on a potential benefit of the passive house approach. And they are particularly encouraging in the light of research from Germany suggesting non-passive house retrofit can make radon levels worse.

RADON

Like the new build passive homes, the Enerphit dwellings had new, airtight floors installed in order to meet the airtightness requirement of the standard. And as mandated by the standard, they all had balanced whole-house ventilation. But research from Germany suggests that in retrofits where wall airtightness has increased but no ventilation is added, radon levels tend to rise. Winfried Meyer from the Federal Office for Radiation Protection in Germany recorded radon levels in just over 100 buildings refurbished to improve energy efficiency, and compared them with nearby unrenovated buildings from the national radon database. Out of 144 rooms in 122 refurbished houses, 33 (almost one in four) of the rooms exceeded the 100 Bq/m3 reference level. However only four of 144 rooms in unrenovated homes – closer to one in 40 – exceeded this level. Radon concentrations of more than 300 Bq/ m3 were found in the living spaces of refurbished homes (five rooms), but in none of the unaltered houses. The refurbished buildings commonly had new windows, and wall insulation (there was no information available about the floors). But “these buildings do not have ventilation systems,” Winfried Meyer reports. “The exceptions are the temporary mechanical ventilation of bathrooms and WCs in a few buildings.” As she writes: “The current energy saving regulation in Germany (EnEV‐2015) stipulates that buildings must be airtight. In most cases however, manual window ventilation is considered sufficient.” The author also looked at radon levels in new passive house dwellings, and found that these were no higher than the national average. This German dataset is not directly comparable with Irish and UK dwellings, as overall radon levels appear lower, and it is not possible to say whether this is a feature of the differences in construction and/or lifestyle, or even geology, between the countries. However, it does highlight a possible risk from retrofit when whole house ventilation, and possibly floor sealing, are not addressed. Meyer concludes that “high radon levels in energy‐efficient houses are not inevitable... They can be avoided by adequate user‐ independent air exchange and by limiting the amount of radon that enters the building.” The role of ventilation A couple of small experiments have demonstrated how effectively mechanical ventilation with heat recovery [MVHR] can remove radon from a living space. Ventilation consultant Ian Mawditt’s own home is in a radon risk area. The house is a low energy retrofit, featuring both highly airtight fabric and whole-house MVHR. Because of the radon risk, Mawditt has also installed a dedicated extract fan beneath the remaining suspended section of floor. (Suspended floors are generally not airtight, and the floor of

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RADON

INSIGHT

SAME HOUSE, DIFFERENT HOME.

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INSIGHT

What about the floor? Alongside the ventilation, another notable feature of certified passive house and Enerphit homes is an airtight floor – necessary in order to achieve the airtightness targets of these standards. This is in contrast to most existing homes and many standard new ones, particularly in the UK. In Ireland, amended building regulations in 1998 required radon preventive measures in new buildings in designated high radon areas. The UK building regulations also require radon protection in higher radon risk areas. In the UK, public health research suggests the presence of a radon barrier does reduce radon levels, with 30% of homes without barriers in high-radon areas having levels of radon above 200 Bq/m3, while only 12% of those with a barrier do. Similarly, Barry McCarron reports, the

Airtightness Level Comparison

ACH-1 @50pa

the undercroft can often be bare earth with no covering, though in this case there is a concrete slab over it). To investigate the role of both systems, he tested the effect of turning them off. The MVHR flow was turned down from 0.4 to 0.1 air changes per hour for two weeks (during a short absence). This saw radon levels rise steeply. After two weeks the level reached around 600 Bq/m3, around ten times the base level. At this point the occupants returned and the MVHR was returned to normal running – which saw the radon clear equally rapidly. Disabling the underfloor extract fan on a separate occasion also saw a rise in radon levels, although not as dramatic. The effect was again reversed when ventilation was re-instated. In a new build passive house in a ‘high-radon’ area in Germany, a similar, if less dramatic effect was observed when ventilation was turned off: radon levels rose between three and seven fold.

RADON

Average Radon Level - Bq/m <0.3 ACH

>0.3 ACH

Average radon levels in passive houses with airtightness less than 0.3 air changes per hour (ACH), versus passive houses greater than 0.3 ACH.

prevalence of above action-level homes in Ireland has decreased since the building regulations were amended. However, radon barriers alone do not guarantee safe radon levels, as the national databases confirm. As Barry McCarron warns, these barriers are not always well installed. “It’s fiddly to install them correctly – the barrier needs to be taped in to preserve the airtight seal. They are also vulnerable to damage before the slab is poured, if care is not being taken on site.” High radon levels have also been observed in homes outside the highest radon risk areas, where protection will not necessarily be mandated. Although guidance suggests a radon barrier

should be installed in such a way as to prevent soil gas leakage into the dwelling, there are no specific installation checks. An even greater concern is radon levels in existing buildings. Many existing homes in the UK and Ireland have suspended floors and no radon mitigation at all. Barry McCarron’s research found a couple of existing homes with very high radon levels among the 25 that were sampled. “My sense is that some of our older stone houses are potentially at high risk of radon build-up,” he says. While new dwellings have at least some purpose provided ventilation, older homes may have blocked chimneys, reasonably

Ceritifed Passive House Radon Montioring Results

Radon Level - Bq/m3

Seasonal Adjusted Average

Certified Passive House Sample Monitored radon levels from 97 passive houses in the study

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RADON

INSIGHT

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Angular selective technology 80 | passivehouseplus.ie | issue 35 Visit us: www.smartlouvre.com

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RADON

Preston Springs (above), a new certified passive house, has much lower radon levels than the 1890s-built house right next door (below).

airtight fabric (possibly including replacement windows) but rely mainly on window opening for ventilation. As was suggested in the research from Germany, energy retrofit may make this situation worse. Suspended floors are often retained unless a very comprehensive retrofit is being undertaken. But the walls, doors and roof may be made more airtight by installing new components, draught-proofing, and insulation. Overall, these studies indicate that combining effective balanced ventilation with a sealed floor (incorporating radon protection if in a high-risk area) reduces radon risk. Both of these features come as standard in a certified passive house or Enerphit. A complete airtight envelope, validated by testing, plus properly designed, installed and commissioned balanced ventilation, are the cornerstones of low energy construction and healthy and comfortable living conditions. They are crucial elements in a radon mitigation strategy, too. There seems little reason not to build, and retrofit, everything this way.

Radon at Preston Springs Preston Springs is a new passive house in Yorkshire designed by architect Mark Siddall. The â&#x20AC;&#x2DC;Radon in Homes in Englandâ&#x20AC;&#x2122; 2016 data report defined the average radon concentration for the Richmondshire district where it is situated as 100 Bq/m3. Preston Springs recorded figures of just 30 Bq/m3 in the ground floor living room and 37 Bq/m3 in the upstairs bedroom. The comparison building right next door, built circa 1890, has more elevated levels of 127 Bq/m3 on the ground floor and 108 Bq/m3 on the first floor, figures more in alignment with the Public Health England data for this postcode area. Overall the passive house radon level is 71% lower than the dwelling next door.

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Marketplace News KORE GETS NSAI CERT FOR INSULATED FOUNDATION

Partel announces RIBA accredited airtightness CPD

artel, a leading specialist in high-performance building envelopes, is currently running a new RIBA-approved CPD programme titled ‘Best Practice for Air and Windtight Structures’. The CPD focuses on the importance of air and wind-tightness in low-energy building design. It discusses the importance of external and internal membranes and their sealing, and highlights best practice on how to specify and install relevant products and components. It also focuses on the risks associated with airtight buildings, and how best to overcome these. Highlights of the CPD include:

ORE has announced that its insulated foundation system has received full certification from the National Standards Authority of Ireland (NSAI) under Irish Agrément Board certificate number 20/0424. This NSAI certificate certifies that the KORE insulated foundation system complies with the requirements of the building regulations 1997 to 2019. The system consists of rigid polystyrene boards cut from moulded blocks of EPS. It is comprised of three components: KORE Floor EPS100 White, KORE Floor EPS200 White and KORE Floor EPS300 White. When used together, the insulated foundation system provides an efficient insulating layer to reduce the thermal transmittance of ground concrete floors. An in-situ concrete slab is poured on top of the insulated foundation. Vertical upstands of insulation are used to insulate the slab from the wall to reduce thermal bridging at the wall to floor junction. The system does not contain CFCs or HCFCs and has zero ozone depletion potential. Like all EPS products, the foundation system will last the lifetime of the building with little to no maintenance required. Apart from the extremely low U-values KORE’s insulated foundation system is able to provide, the wall to floor cold bridge is virtually eliminated by essentially wrapping the entire foundation in a layer of EPS insulation. In addition, the system is fully engineered and manufactured off-site. Once delivered to the job site, the foundation system can be installed in just a few days. KORE’s insulated foundation system assists with lean construction methods, reducing material, on-site waste and the required labour for installation. It can be provided for one-off self builds, or can be manufactured to supply even the largest developments across the country. For more information see www.kore-system.com. •

• • • • •

Correct product choice for specific scenarios Correct detailing and specification for optimum results How to determine where an airtight layer should be How to specify correct components for varying scenarios Airtight principles and associated risks

Partel’s ‘Best Practice for Air and Windtight Structures’ RIBA CPD will be held online for the rest of 2020 via Microsoft Teams. This is a unique opportunity for architects, engineers, and construction and design professionals to gain up-to-date knowledge on a range of innovative products and techniques, earn CPD points, and enhance their personal proficiency in airtightness. Being a RIBA approved CPD, attendees can also earn up to eight CPD points. To book please e-mail contact@partel.com or visit www. partel.ie/cpd-and-training for more information. • (below) Partel’s CPD on best practice for air and wind-tightness is RIBA approved.

(above) KORE’s insulated foundation system.

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OFFSITE AND MODULAR:

THE FUTURE OF CONSTRUCTION — LIDAN DESIGNS NEW CORK SCHOOL BUILT AND FINISHED IN 4 WEEKS

The new classrooms building at St Patrick’s College Cork, built by Lidan Designs.

ffsite, modular building using sustainable materials is increasingly seen across Europe as a solution to construction delivery challenges, because it can deliver high quality buildings to extremely fast turnaround times. That’s according to Roscommon-based offsite craft building specialist Lidan Designs. Lidan recently completed a modular building with two classrooms and an office for St Patrick’s College in Gardiner’s Hill, Cork City. The A rated NZEB building took just three weeks to build in the Lidan factory, and another week to erect and install on the difficult-to-access site. The classroom building was finished with traditional render, with a zinc roof,

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aluminium doors and windows. In line with their sustainable ethos Lidan also built a wooden ramp clad in cedar. “The building has been very well received by the school and their board of management, teachers and pupils. The school consultants Matt O’Mahony & Associates in Cork said it has far exceeded all their expectations,” Dan O’Brien of Lidan Designs told Passive House Plus. O’Brien believes this type of building represents the future of school construction as it allows schools to order modular but bespoke buildings with extremely fast delivery times compared to traditional onsite building options. “It’s a permanent building, but it’s modul-

arly done, completed offsite and portable,” O’Brien said. “In my opinion here in Ireland my experience is that there is too much focus on temporary or emergency solutions across the board. This is a function of continuous ineffective strategy, but possibly driven by a lack of alternative solutions, which modular is now changing. Proper forward planning with demand estimation etc. can and will alleviate the need for so-called temporary or emergency solutions.” O’Brien said that the Department of Education and Skills in the main have standard design and specification guidelines for school buildings, but at the same time every school wants or requires a different size. That makes school buildings

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Ultra-low carbon Lidan specialises in small modular buildings such as home offices, classrooms and garden rooms. The company also recently supplied an A2 rated NZEB dwelling for Dún Laoghaire-Rathdown County Council

For more information see www.lidandesigns.com.

Embodied Co2e: completion vs end-of-life 500 Carbon Emitted >

Wet and windy “We also know that it’s more difficult to deliver airtightness and insulation details on a wet and windy building site,” O’Brien said. “By taking it fully offsite, we can deliver guaranteed build times to NZEB standard. This makes it ideal for school building, where delivery often needs to be to very specific timetables.” He continued: “We endeavour to use our own full-time tradespersons, rather than subcontractors, meaning we have more control over sequencing and quality. Completely finishing a building offsite is the key thing in terms of saving time. And because we are not delayed on site, we can guarantee a finished price too. What we have done is to have set per square metre pricing for buildings, which means we are reducing the risk to the end client and procurement leads. “There is a huge move to offsite now. In the UK this has been driven by the government, a push towards modular and factory-built solutions, even to the point where the government there is now directly assisting modular providers.”

kg CO2e/m2 NIA

ideally suited to offsite modular construction, but where there is an ability to make different size buildings. “Lidan prides itself on its flexibility in this regard and we can work from the same template but adapt it as needed in the factory,” O’Brien said. “While there are many different definitions of modular, prefabricated and rapid build, what we have endeavoured to provide is a fully finished offsite building. This for example includes all internal plumbing and electrics up to and including the colour of paint on the walls and the external render. It’s a ‘plug and play’ offering essentially. You’re talking four weeks to deliver 1,400 square feet to NZEB standard. This includes the high levels of insulation, airtightness and designed ventilation needed to provide a warm, comfortable and healthy indoor environment for learning.” He continued: “And because we are operating offsite, we can ensure quality at speed. Research shows across Europe that a lot of time — up to 50% is one estimate — is lost with traditional onsite construction due to the challenges of dealing with weather, sequencing, and subcontractors etc. We’re not saying all construction solutions will move to offsite, but it has a big part to play going forward.” Lidan Designs is based in Roscommon town and makes all of its buildings in its factory using sustainably sourced timber and other natural materials.

that Passive House Plus believes is the first dwelling in Ireland to be completely finished offsite, including fitted bathrooms, bedrooms and living spaces. The dwelling was installed using a ground screw system, negating the need for concrete foundations, and significantly reducing delivery time. The dwelling also boasts a remarkably low embodied carbon score. According to an analysis carried out by Tim Martel, it has a full ‘cradle to grave’ embodied carbon of 157.3 kg per square metre, and a ‘cradle to factory gate’ figure of 176.4 kg per square metre. For comparison, both figures are about half the 300 kg that the Royal Institute of British Architects (RIBA) has challenged architects to achieve under its 2030 Climate Challenge. “This analysis demonstrates that our buildings are sustainable not just in terms of operational energy but also in terms of the embodied carbon of their production,” O’Brien said. Lidan also recently completed executive offices for the Castle Leslie Estate and has produced a number of buildings for the Office of Public Works. The company has also recently started supplying pre-finished but bespoke home extensions, which can be delivered in rapid time. To see a Matterport 3D tour of finished classroom buildings at St Patrick’s College, go to tinyurl.com/LidanCork. The Matterport tour was produced by 2eva.ie.

400

300

EMBODIED CARBON GRAPH?

200

100

< Carbon Stored

Lidan Designs specialises in small modular buildings, constructed and finished offsite; (bottom right) the house built by Lidan for Dún Laoghaire-Rathdown County Council boasts a remarkably low carbon footprint.

MARKETPLACE

-100

-200

-300

Cradle to practical completion

Cradle to grave

C: End of life

Zinc

B: Use phase

Steel

A4/A5: Transport/construction PV

Plasterboard Cellulose Timber

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Beam announces next-generation HRV B

eam Vacuum & Ventilation have launched their new range of HERU heat recovery ventilation systems, combining a sleek new design with award-winning rotating heat exchanger technology. Based on a mission to create first class indoor air environments, the new range features an energy efficient rotor motor, as well as an innovative regenerative, non-gyroscopic, aluminium heat exchanger for optimal heat exchange. The all new intelligent control system includes an app-ready 4.2” touch panel, connected wirelessly to the HERU unit. This panel can be placed within the home, within 50 metres of the unit. The new control system also provides the ability to manage and monitor the HERU unit through a smartphone app for the ultimate in accessibility and convenience. For further information visit www.beamcentralsystems.com. •

new housing development in Leopardstown, County Dublin is just the latest scheme to hit NZEB with the help of Daikin Altherma air-to-water heat pumps. The second phase of Clay Farm, by leading developer Park Developments, features a mix of three and four-bed timber frame homes with A2 BERs. Each dwelling has been fitted with a Daikin Altherma 3 air-to-water heat pump for central heating and hot water, along with thermostatically controlled low temperature radiators, and a Heatmiser Neo smart control system and app, with thermostats both upstairs and downstairs. Each Altherma unit has a 180 or 230 litre hot water cylinder, depending on the

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(above) The new Beam HERU heat recovery ventilation system and touch panel for intelligent control.

Daikin heat pumps chosen for Clay Farm NZEB scheme dwelling size, integrated into one highly insulated and sleek fridge-like indoor unit. “Even at the lowest temperatures the Altherma 3 can produce heat, even down to -15 C,” Ian Killoch of Daikin Ireland said. “It’s a very simple heat pump to use, and there are thermostats upstairs and downstairs, so that’s all the homeowner ever has to use.” He continued: “This compressor works so efficiently and so fast that if you like it can produce water at 60 C. But what we’re trying to do, to make it very efficient, is keep the flow rate around the radiators at 45 C, while the hot water in the cylinder is kept around 45 C too. This is to keep the running costs down even more.” Disinfection is controlled automatically by the heat pump to bring the hot

water to 60 C for one hour each week. All plumbing and heat pump installation on phase two of Clay Farm was completed by Jonathan Kelly of TC Heating & Plumbing. Each dwelling is also fitted with a mechanical ventilation with heat recovery (MVHR) system to provide fresh, filtered, pre-heated air. Clay Farm is within walking distance to the Leopardstown Valley Luas stop. The dwellings are also pre-wired for electric car charging, and the development features 14 acres of eco parkland with tracks, a cycling greenway and playground, all adding to its sustainability credentials. • (above) The Daikin Altherma 3 heat pump at Clay Farm.

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KILSARAN PUBLISHES EPDS AS PART OF GREEN JOURNEY

Kilsaran’s dry products manufacturing facility in Co Kildare.

eading cement products manufacturer Kilsaran has become the latest Irish building materials company to publish Environmental Product Declarations (EPDs) for some of its key products. Kilsaran International is Ireland’s leading independent supplier of concrete building materials including ready-mix concrete, aggregates, bituminous products and surfacing, paving, masonry and block products. The company published its first two EPDs earlier this year. This first EPD is for a range of its paving block products comprising Newgrange 80 mm silver granite, Clima Pave 60 mm Curragh Gold, and Corrib 60 mm black granite. The second EPD is for its M4 Masonry Mortar. These are the first EPDs on the Irish market for heavy construction products. Environmental Product Declarations provide independent verification of a product’s environmental impact across a range of different parameters, from global warming potential to eutrophication, acidification, ozone depletion and natural resource depletion. “It allows the purchaser to specifically examine the performance and impact of similar products in an accurate way,” said Kilsaran’s group technical manager, and head of sustainability, Keith Goodwin. “This journey for Kilsaran allowed us to clearly see which materials and production processes have the greatest environmental impact and to review and adjust where necessary, as well as look at alternative supply chains to improve the performance of our products.” “The EPD journey is very much in its infancy in Ireland. The level and detail of data gathering is very complex and the process of creating an EPD takes considerable time and input.” Kilsaran’s EPDs were produced by leading life cycle assessment consultancy EcoReview. Goodwin said that for Kilsaran, who produce many different products across

several sites, it will take some time before EPDs are available for all its products. But he added: “EPDs are however being warmly welcomed by specifiers and industry as a progressive step in transparency of the impact of products across their lifecycle, and Kilsaran are delighted to be one of the first to take a step forward in this area.” The move to publish EPDs is just one part of what Goodwin calls the company’s journey from “grey to green”. He explained: “For example the company have comprehensive objectives around efficiency as exampled by transport and logistical arrangements,” he said. “Over 80% of aggregates are transported 40 km or less from extraction to use, which is significantly below industry average. In addition, the business has eliminated the use of pre-Euro VI trucks in the fleet, also an industry first. Euro VI trucks have among other benefits, NOx emissions of approximately 90% below that of Euro III trucks.” “In addition to minimising transport distances of bulk raw materials, all wash and process water in concrete production is fully recycled, rainwater harvesting is used in production factories and by-products and waste from other industries such as china clay stent from the paper industry can be incorporated into concrete products.” Goodwin says the company has also been working hard to reduce the local environmental impact of its quarries and factories. He said that as a matter of course in-depth planning, consultation and environmental impact assessments, including extensive bio and geodiversity reviews, are conducted for all new and existing sites. “We have a dedicated planning and environmental management team with significant expertise in this area. Quarry facilities are fully planned and designed through their lifecycle. This includes development and landscaping works prior to operation, to minimise visual and audible impacts, bio and geodiversity protection measures during operation, and also for

end of life to restore facilities to beneficial use, including amenities such as wetlands.” “Quarries also provide unique habitats for wildlife even during operations, such as sand martins which breed in burrows dug into stockpiled sand. One active Kilsaran quarry even has a breeding pair of peregrine falcons in residence.” Goodwin says that in recent times, traditional construction materials have been challenged by construction professionals as building requirements, performance and demands for sustainability all rapidly advance. “Recognising this, we employ a team of concrete technologists who review customer and project requirements and design materials that have to balance engineering performance, cost optimisation and more importantly than ever, minimal carbon footprint and environmental impact.” Goodwin says that the concrete industry in Ireland is unique in Europe in that principally CEM II is used for most concrete production, and offers a reduced carbon footprint over CEM I or traditional ordinary portland cement, which are used more commonly in the UK and EU. Other supplementary cementitious materials such as GGBS (a by-product from steel production) and PFA (a waste stream from coal fired power stations) are also commonly used to reduce the use of cement and thus the carbon footprint of concrete products. Goodwin says that Kilsaran employs over 700 people and supports more than 250 further personnel who operate as key contractors. “Due to the nature of aggregate production and processing, many of these operations are in rural areas and therefore anywhere from 20-50 personnel are employed in each location. This provides sustainable, long term employment and associated socio-economic benefits to regional and rural communities where local, high quality job opportunities are often not there even in buoyant economic times.” “Long term integration in the community is a key value at Kilsaran and in addition to the provision of employment this is achieved through sponsorship of local initiatives and provision of resources and materials, such as recent projects including surfacing works to Lann Léire GAA Dunleer, Co. Louth and the field of dreams sensory facility for Down Syndrome Cork. A family owned and managed company, Kilsaran has been in operation for over 55 years and now operates out of 24 locations in Ireland, as well as having a presence in the UK. •

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NIBE CELEBRATES 20 YEARS IN IRELAND

Nils-Ove Johansson and Margaret Sheeran’s Swedish-made timber frame house, built in the year 2000, where two NIBE Fighter 310P exhaust air heat pumps are still going strong.

eading Swedish heat pump maker NIBE is celebrating its 20th anniversary in Ireland this year, with the news that two NIBE heat pumps that were installed in Cork at the turn of the millennium are still in excellent working condition. Two NIBE Fighter 310P exhaust air heat pumps were installed in the house of former Swedish trade commissioner Nils-Ove Johansson when it was built 20 years ago. “They are still working perfectly since installation in springtime 2000, twenty years ago,” Johansson told Passive House Plus. Johansson explains that between 1998 and 2000, he surveyed the Irish market to find a suitable distributor for NIBE. “I met approximately 15 different companies,” he said. “I finally narrowed it down to three companies and had further meetings with them. I had to convince the remaining companies that this was the future of heating systems for Ireland. “In the end I recommended Unipipe which was the smallest of the three remaining companies on the shortlist, but I believed they had the best operation to take on a project like NIBE, not least due to [Unipipe managing director] Paul O’Donnell’s enthusiasm for the products he already represented. Despite the size of one’s company, if one is enthusiastic and believes in the product success will come eventually, especially if you have a high-quality product like NIBE.” Johansson’s own house ended up being NIBE’s first project in Ireland. At the time,

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he and his wife Margaret Sheeran, who was also working to promote trade with Sweden, started looking for somewhere to settle down. They found a suitable site on a hillside outside Cork City and applied for planning permission. From the outset, their house was designed to have very low energy consumption. They imported a timber frame system from Sweden, and laid a raft foundation with 300 mm of polystyrene insulation, at a time when the building regulations only required 50 mm. “We included underfloor heating pipes in the foundation also,” Johansson says. “Special polystyrene perimeter edges also were used into which concrete was poured— the first foundation of its kind in Ireland.” The walls and attic of the house were insulated with 240 mm and 400 mm of mineral wool respectively. Triple glazed windows were also installed. The house was built by four Swedish carpenters over three weeks, together with local electrical and plumbing contractors. “Our two NIBE heat pumps are the first and oldest NIBE heat pumps in Ireland and are 20 years in operation,” Johansson said. “They are connected to the built-in mechanical ventilation system from Sjodalshus which ensures clean, healthy, fresh air with low humidity.” The system recovers heat from outgoing stale air in wet rooms and uses it to provide heat to the underfloor heating system, while also delivering fresh air to living spaces. The house was used for 15 years as a

show home to promote Swedish-made houses, windows, doors and heat pumps. Margaret Sheeran became the Sjodalshus representative in Ireland and established the Swedish Trade Centre Ltd office. Unipipe is still NIBE’s distributor in Ireland. “The general public perception of exhaust air heat pumps is that they are something new, but in fact we’ve been distributing the technology in Ireland for 20 years,” Paul O’Donnell told Passive house Plus. “Air-to-water heat pumps tend to be the most popular type of heat pump in Ireland, but in Scandinavia exhaust air is probably more popular.” While air-to-water heat pumps are perceived as less than expensive than exhaust air, the former requires the installation of a separate ventilation system, while the latter does not. This makes exhaust air heat pumps competitive on price overall, O’Donnell said. Today Unipipe sells NIBE exhaust air heat pumps up to 6 kW in output, with new models soon to be announced. These can also be combined with outdoor air intake units to provide extra heating capacity. Larger NIBE units are also available in ground and air source heat pumps. The company’s line up will be updated shortly as NIBE expands its S series range, currently already available in ground and air source heat pumps, into its exhaust air line up. The new S range features in-built smart technologies such as weather forecasting and compatibility with home voice assistants. For more see www.unipipe.ie. •

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Expert, impartial advice key to quality ventilation — AerHaus

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Small is beautiful for Ecocel

well-designed, well-installed ventilation system is one that your ear will not tell you is running, but your nose will tell you when it’s not. This is the belief of Stephen Walsh, managing director of AerHaus Ventilation, and he says that having access to a broad range of ventilation solutions is key to achieving this. Choosing the correct and most suitable ventilation system for your home is critical in ensuring occupant health and comfort, particularly as insulation and airtightness levels improve. But Walsh says that it can be difficult sometimes to find expert independent advice as many equipment suppliers, while well intentioned, are single brand companies. AerHaus specialises in heat recovery (MVHR), demand controlled (DCV) and centralised mechanical extract (cMEV) ventilation. It represents leading ventilation brands from Belgium, the Netherlands, France, Germany, Italy, and the UK. Walsh says the company’s experience of working with this broad range of manufacturers allows AerHaus to offer clear, independent advice to its customers. AerHaus supplies seven different ranges of MVHR systems, four different DCV brands and four types of duct systems. Walsh firmly believes there is no one company that makes the best of everything as each has its strengths in a niche area of the market. He said that working with multiple manufacturers allows AerHaus to cherry pick the most suitable duct system along with the most suitable ventilation unit, in many cases from different manufacturers, and put them together to ensure a bespoke system for each and every project. He continued: “We believe in a warts and all approach — we give our customers unbiased information, honestly going through the advantages and disadvantages of each option so they can make an educated and informed choice.” AerHaus operates from its 10,000 square foot facility in Dungarvan, which includes offices, showroom, training centre and warehouse. The company also has a large network of installers nationwide, including specialist ventilation contractors, as well as undertaking installation and commissioning services itself in the Munster area. All the company’s technical staff are accredited by the City & Guilds and WWETB to the new NZEB standard. AerHaus is also accredited by the NICEIC and BPEC training bodies in the UK. Stephen Walsh is also the chairperson of the newly formed Residential Ventilation Association of Ireland (RVAI), which aims to promote ventilation and indoor air quality standards across the building industry. To satisfy a growing demand for its services, AerHaus is looking for additional ventilation partners nationwide. For more information email info@aerhaus.com.

AerHaus managing director Stephen Walsh

ork-based cellulose insulation manufacturer Ecocel continues to grow its business as the company aims to deliver on its mission of producing sustainable, low carbon, natural insulation for the Irish market and beyond. In the past two years, Ecocel has expanded the brand via its Ecocel Scotland partner firm, and Ecocel Ireland managing director John Egan told Passive House Plus that while he is keen to grow the brand, it must be in a sustainable and local fashion. “Ecocel Scotland currently imports its cellulose insulation from us here in Cork, but our plan eventually is to help them set up a manufacturing plant in Scotland. For their carbon footprint in the long run it would be better if there was a factory over there, and it would help to keep transport costs down too,” he said. “I believe in keeping it small and local. The size we are at now here in Cork is perfect. My vision would be to establish local Ecocel plants in different markets, each using local newsprint to make their own cellulose insulation and supplying their own local market.” Egan said that the Ecocel Scotland business had been boosted by an update to the company’s NSAI Agrément cert stating the product is suitable for use against natural stone walls, as there are a lot of buildings of this type in Scotland in need of retrofit. Ecocel manufactures its cellulose insulation in Cork from recycled newsprint sourced within Ireland. Two years ago, the company licensed the brand name to Ecocel Scotland, which began supplying Irish-made Ecocel to the Scottish market. Egan’s own background is very much tied up in paper. His father worked as an accountant at a paper mill in India, and later at Clondalkin Paper Mills in Dublin. He previously ran the company Healthbuild, which supplied natural building and insulation materials, but bought Ecocel from liquidators in 2010 with the vision of producing locally made insulation from recycled newspaper. For more information see www.ecocel.ie. • (above) 225 mm of Ecocel was used to insulate both the floor and ceiling of this low energy home to a U-value of 0.14.

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PA S S I V E H O U S E +

STRONG DEMAND FOR GGBS FROM IRISH MARKET

here is strong and growing demand for GGBS on the Irish market, according to leading Irish supplier Ecocem, as the company gears up to respond to a market and regulatory environment that is increasingly demanding low embodied energy construction products. Speaking to Passive House Plus, Ecocem Ireland managing director Susan McGarry said that there is an ample supply of GGBS available to meet this demand, despite recent rumours of GGBS supply shortages. McGarry told Passive House Plus that the company’s strong partnership agreements with suppliers ensure it can meet growing demand. “We have a capacity for 350,000 tonnes of GGBS annually for the Irish market. We only closed for one week during lockdown and are now about to embark on a new programme of CPDs to help architects and specifiers to understand our products better.” McGarry told Passive House Plus that Ecocem has a long-term partnership agreement with ArcelorMittal, the world’s largest steel producer, to ensure a continuous supply. In 2016, the two companies invested in a joint production facility in the north of France. “Even if or when there’s a general slowdown in the general steel industry, we are able to maintain

our supply lines,” she said. GGBS, or ground granulated blast furnace slag, is a by-product of steel manufacturing that can be used an alternative to ordinary portland cement. McGarry said that in the current climate there is a particular focus on reducing the carbon footprint of construction products, with the European Green Deal coming to the fore, Ireland’s new programme for government explicitly recognising the need to set climate targets in the cement industry, and the growing demand for construction product manufacturers to publish environmental product declarations (EPDs). Ecocem published its first EPD in 2014, the first one published in the UK and Ireland for a cementitious product. “We’ve reduced the carbon emissions of the cement industry by 12 million tonnes over the past 17 years,” McGarry said. “We’ve invested a huge amount in innovation as well. We spend €2m each year within the Ecocem Group on research and development, including into new sustainable cement types, activation for GGBS, cement-free technologies, and new GGBS-based products like screeds and shotcrete.” For more information see www.ecocem.ie. •

Ecological launch new airtight vapour boards

cological Building Systems have added FINSA superPan VapourStop passive house certified boards to their range of products. FINSA superPan VapourStop is an innovative wood particle board with a unique composition which differentiates it from other conventional boards on the market. It features a high performance P5 inner chipboard layer, enclosed within two layers of high density woodfibre on either side, followed by a specialist airtightness film pre-applied on either side of the board. This unique composition ensures superPan VapourStop fulfils three criteria within one panel: it provides a certified airtight barrier, the vapour control element prevents condensation build-up within the fabric of the building, and it offers high levels of structural stability for timber elements. VapourStop has been used successfully on projects achieving passive house levels of airtightness and has been certified by the Passive House Institute to the highest airtightness category, pHA. All timber harvested for production is sourced from responsibly managed forests and the boards are also EPD certified. The Eurofins Institute conducted tests to determine VOC and formaldehyde emissions, and FINSA obtained a Class A+ by French standards. Niall Crosson, group technical manager with Ecological, said: “We are delighted to partner with FINSA in the establishment

90 | passivehouseplus.ie | issue 35

MEMBRANE

BOARD CORE

WOOD FIBRE

Layer of chipboard with high moisture resistance resins, allowing its use in moist environments, up to Service class 2.

Layer of wood fibre providing excellent airtight qualities.

Special film on the two outer faces, providing the board with water vapour diffusion resistance.

COMPOSITION By pressing the layers together we achieve a synergy that provides the product great stability, high performance and high structural capacity.

FINSA superPan VapourStop, new to the Ecological Building Systems range

and exclusive supply of their range of innovative superPan boards in Ireland and the UK. The unique technical characteristics of the VapourStop board and its certification and environmental credentials make it the perfect partner for our range of innovative airtightness solutions.” The product is classified as a P5 moisture resistant board, suitable for structural use, with omnidirectional resistance meaning it has equal resistance when applied in any

direction. “It is a very reliable substrate to screw and fix to with no breakout, and is very easy to cut with standard cuttings tools on site,” said Crosson. Further details and information can be accessed at www. ecologicalbuildingsystems.com. Ecological also said they have experienced increased demand for their virtual CPDs, training courses and webinars which are available to book at www. ecologicalbuildingsystems.com/cpds. •

PA S S I V E H O U S E +

Get up to NZEB with Grant heat pumps

MARKETPLACE

Kingspan launches new thin K8 partial fill insulation

igh efficiency is a hugely important factor in choosing a heating system and this is a key priority for industry leading manufacturer Grant, whose wide portfolio of heating technologies has advanced over the years and now includes air source heat pumps, underfloor heating, pre-plumbed hot water cylinders, aluminium radiators and fan convector radiators. Grant says its A+++ Aerona3 R32 air source heat pump range is the manufacturer’s most sustainable main heat source and is an ideal option for properties of varying sizes, and for deep retrofits. The company said this air-to-water heat pump range is extremely popular amongst Ireland’s self-builders, as the units can help to achieve nearly zero energy building (NZEB) standards. Available in outputs of 6 kW, 10 kW, 13 kW and 17 kW the Grant Aerona3 R32 inverter driven air source heat pump range offers cleaner, more environmentally friendly performance, and can lower a property’s overall carbon footprint and annual heating bills, the company said. All four models also boast “superior” seasonal coefficient of performance (SCOP) figures. According to Grant, even if external temperatures were to drop as low as -20 C, the heat pump’s output will modulate up or down depending on the exact climate conditions to ensure ultimate energy efficiency for the property. As the Aerona3 R32 air source heat pump can run at both high and low temperatures, it can work in tandem with other technologies featured within Grant’s ‘multiple package solutions’ offering, including the Uflex underfloor heating system. When paired together, the Aerona3 R32 air source heat pump and Uflex will improve the overall efficiency of a new build or deep retrofit property as both can run at lower temperatures, therefore providing significant carbon and financial savings for the property owner. The Grant Aerona3 R32 13kW and 17kW models have also been recognised by Quiet Mark for their quiet operation. Quiet Mark is the international award programme validating and awarding low-noise, high-performance technologies. Visit www.grant.eu for more information on Grant’s range of innovative heating solutions. • (above) The Grant Aerona3 range of heat pumps

The new Kingspan K8 partial fill solution boasts thermal conductivities as low as 0.020 W/mK.

ingspan Insulation has announced the launch of its Kingspan Kooltherm K8 Plus partial fill cavity wall solution. This new cavity wall insulation system is a premium performing partial fill cavity wall insulation which allows a reduced minimum clear cavity width of 20 mm with thermal conductivity values as low as 0.020 W/mK. It is ideal for new builds and extensions. K8 Plus is designed to be quick and easy to install, saving time on-site and producing less site waste. K8 Plus can be combined with other Kingspan insulation systems for floors and roofs to create a complete high-performance building envelope (see the detailed case study on Mel Reynolds’s passive house plus in this issue for an example of such a project). For those specifying its products, Kingspan has developed a technical service offering designed to offer peace of mind to architects, engineers, contractors and homeowners. Kingspan’s premium service offers a wide range of free benefits to ensure that the insulation installed on site meets its standards. There are two different levels of premium service depending on your project type. Kingspan Premium Service is designed for homes achieving better than an 0.15 W/m2K area weighted average U-Value and using Kooltherm products in at least two building elements. This service includes: • Consultation service • Pre-tender KoolSpec check service • Project specific warranty • U-Value calculations / condensation risk analysis • Response within 24 hours to all issues • Performance specifications • 2 x site inspection visits Kingspan Premium Plus service is designed for homes achieving a better than 0.13 W/m2K area weighted average U-Value and using Kooltherm products in at least three applications. It includes all of the above plus performance specifications, five site visits, pre-design assessment of details, certification of installation, BER/SAP calculations, and a toolbox talk/installation training. Kingspan Insulation are also currently running a series of live online CPDs — KingspanLive. For more information see www.kingspaninsulation.com. •

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PA S S I V E H O U S E +

Passive Building Structures delivers bespoke Manchester passive house

eading ICF building envelope specialist Passive Building Structures is currently on site completing a large new passive house in Didsbury, Manchester. The project offers a contemporary take on the surrounding traditional architecture. The building, with a floor area just under 5,000 square feet over three floors, uses the full integrated Passive Building Structures system to meet passive house airtightness, U-values and thermal bridging requirements. Floors, walls and roof all meet a U-value of 0.11. This includes an insulated raft foundation with two layers of 150 mm EPS, plus ICF walls which feature a 200 mm concrete core sandwiched between an inner layer of 108 mm EPS and an outer layer with 108 mm plus another 102 mm EPS. “Our rapid roof ultra-panel which consists of 300 mm EPS has also been engineered to eliminate any purlins or collar ties so promotes open plan living,” Pearce McKenna of Passive Building Structures told Passive House Plus. The company also supplied and erected internal load bearing ICF walls, while the house also features precast concrete floors and internal stairs on two floors. There is also a 1.5 metre cantilever to the front elevation on the first floor, which had to be offset for protection of tree roots on site. “This cantilever is incorporated into the building envelope and is fully insulated to ensure zero cold bridging,” McKenna said. “The cantilever has been designed with reinforced concrete beams integrated into the wall and insulated raft foundation.

This has eliminated the need for exposed structural steels.” Passive house certified windows and MVHR will soon be installed at the project. McKenna said the principal thing that sets Passive Building Structures apart from other ICF suppliers is that the company delivers a complete thermal building fabric on its projects. “We have incorporated unique details into our system whereby all our components are interconnected/integral elements. Our system is poured monolithically from floor to floor.” The company has particular experience in delivering bespoke high-end developments, such as architect Donn Ponninghaus’s RTE Home of the Year winning passive house in west Cork, which was previously featured in Passive House Plus. For more information see www. passivebuildingstructures.com. You can also follow the Didsbury project on the company’s Instagram page (@pbs_icf). • (below) The new passive house in Didsbury is built with the Passive Building Structures full building envelope system.

Xtratherm offers remote one-to-one support for self-builders

lanning a self-build in the current climate brings its own set of challenges, which is why insulation manufacturer Xtratherm has launched a remote consultancy service dedicated to self-builders as part of the company’s Xi Platinum Service. Available online or by phone, the one to one sessions are held with the company’s dedicated technical team, which boasts over 30 years’ experience of self-build as well as a host of knowledge around issues affecting building performance. Interested persons can simply book a call or online meeting and the team will answer any questions on achieving NZEB, including on topics related to airtightness, building systems, glazing, heating systems, passive foundations and many other self-build topics. The technical team will look at project designs, undertake calculations and complete a DEAP energy calculation. The Platinum Service for selfbuilders can be availed of on projects where at least one other Xi product is used along with an Xi cavity wall system achieving a U-value of 0.15 or better. For more information, please visit the remote support section of the Xtratherm website at xtratherm.ie/ remote-support. •

S U S TA I N A B L E B U I L D I N G

81% of readers

have made decisions on projects because of adverts in Passive House Plus* Contact us for more information on how your brand can feature in our next issue.

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MARKETPLACE

WHY SHADING WILL BE CRITICAL IN THE AGE OF COVID Over the coming years there will be growing demand for openable windows in our office buildings to help prevent virus transmission — which is why high-quality solar shading will be more important than ever, says Smartlouvre managing director Andrew Cooper.

Smartlouvre’s MicroLouvre shading system consists of a fine bronze allow mesh.

he uptake of building certifications and accreditations that consider the wellbeing of occupants has proven that the building user’s comfort and contentment have been growing considerations for architects and building engineers in recent years. For example, since its launch six years ago, the WELL Building Standard, which focuses on a building’s effect on health, is now being applied by 4,421 projects across 63 countries. This includes both commercial and residential properties with the objective of advancing health, human experience and wellbeing through good design. Without warning we find ourselves in a world completely turned around by a pandemic, where the wellbeing and safety of occupants has now become a key focus for all building owners and building service managers. It has been accepted that Covid-19 will not be eradicated anytime soon. It is changing the way we design the workplaces of the future. Architects are currently altering building plans to accommodate CIBSE guidelines for increasing ventilation and introducing room cooling strategies that don’t rely on recirculating air conditioning systems. At the same time, building owners and service managers of existing buildings are seeking ways in which to upgrade and retrofit to ensure that the risk of virus transmission is limited, whilst trying to provide occupant comfort and manage the risk of overheating. With much of the world’s population working from home and for much of it ‘locked down’, we have been made very aware of the

impact our homes have on our wellbeing. We have improved our homes and gardens, for the benefit of our physical and mental health. We have enjoyed the space, the safety, and the comfort of the homes we have created to our own personalised needs and wants. This autumn, many of the world’s population face returning to the workplace after months at home, to spend nine-to-five in a building where our needs are not ‘personally’ met. Workplaces that may previously have provided comfort and familiarity are now changed by the pandemic. Screens and other safety precautions have been introduced and soft furnishings removed or replaced so that we have only stark, wipe-clean surfaces to protect us from the risk of virus transmission. The visible changes to the workplace are immediately apparent. But the invisible changes like the lack of air conditioning or reduced air flow, could have even greater impact on workplace comfort and wellbeing. Since the outbreak of coronavirus, the ventilation strategy of all shared spaces needs review. CIBSE’s advice is to increase ventilation as much as possible, increasing the flow of outside air and preventing any pockets of stagnant air. Workplaces that lack good air quality, natural lighting or temperature control have a huge impact on workers’ energy and remove any chance of creative thinking. More importantly, thermal comfort has a proven effect on our ability to make good decisions and even on taking risks with our safety. For example, people might not wear

personal protective equipment properly in hot environments. As well as being a key option for limiting virus transmission, increasing air movement by introducing natural ventilation can also help to control thermal comfort. Furthermore, directing the fresh air upwards allows for displacement of hot indoor air that has risen to the ceiling, with cooler air from outside to further reduce the indoor temperature. Wherever possible we need to increase the amount of indoor air that is replaced by outdoor air. Operable windows are all too often taken for granted in office buildings, and their importance overlooked. Natural ventilation will play an important role in the future of our buildings, along with mechanical ventilation using fresh air, both for limiting the risk of virus transmission but also for reducing energy consumption, carbon emissions, and building running costs. However, with the benefits of open windows comes the need to manage heat and glare. Internal blind systems remove visibility out and a connection with the outside world, and only protect the room from a minimal amount of heat gain. External shading systems do work but are expensive to install and maintain as well as reducing the quantity and quality of daylight and vision out. Smartlouvre’s MicroLouvre product, designed as a solar shading window screen, consists of a fine bronze allow mesh, comprising 700 tiny ‘bris-soleil’ fins per metre of fabric, measuring only 1.5 mm in depth. It is installed on a frame external to any windows, allowing heat to accumulate on the surface of the metal and then dissipate to the outside before it reaches the window. The heat is blocked before it hits the glass, by a metal fabric, with micro fine louvres woven in to dissipate the sun’s heat and energy but not block natural daylight, natural ventilation or vision out. The louvres are micro fine, and angled at a level to ensure optimum light in, and visibility out, whilst protecting building occupants from the heat, glare and even external viewing in. It’s known as angular selective technology. The 80% open area and angle of the louvres allow natural ventilation in a laminar flow with a distinct upward trend, directing the outdoor air towards the ceiling inside the building. With its passive, angle selective, maintenance free technology, MicroLouvre supports all today’s energy saving, occupancy comfort and sustainable building performance requirements. To find out more about MicroLouvre go to www.smartlouvre.com. •

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T O BY C A M B R AY

COLUMN

The condensation myth Condensation within the structure of buildings is a lot more complex than condensation in a sweaty pub on a Friday night, writes building physics expert Toby Cambray.

n lieu of the real thing, I invite you to join me in an imaginary trip to a packed pub on a Friday evening. If convenient may I suggest The Crown, Cricklewood, whence we may return to discuss building physics on subsequent occasions. The tribute band are on the stage and several tipsy people are dancing away, sweating profusely. The windows are closed in an attempt to keep the noise in and the wind out. You order a bottle from the fridge, and as you hand over your cash, droplets of water condense on the cold, impervious surface of bottle. Condensation, in the sense that most people understand the term, is pretty rare in buildings. You might be surprised to hear that as a specialist in moisture risk, I don’t often worry about it (at least not with respect to this popular definition). A simple definition of condensation is moisture forming into liquid drops when warm moist air hits a cold surface. This is more an observation than a definition and doesn’t tell the whole story.

A building can in principle go mouldy without ever experiencing condensation. Air can hold a certain amount of water vapour, but that amount varies with temperature. Warmer air can hold more, colder air less. Relative humidity (RH) is the degree to which this carrying capacity is used. If you take some moist air and cool it down, the absolute amount of moisture doesn’t change but the RH goes up; cool it enough and you’ll get to 100%, at which point the moisture will form a liquid wherever’s convenient. A more thorough definition considers the matter in terms of vapour pressure. Vapour pressure is a tricky concept. Another name for vapour pressure is partial pressure, which means the fraction of pressure in air (or another mixture) due to water vapour or another gas. So at one atmosphere of pressure, water vapour might be ‘responsible’ for say 2.3 % of that total pressure, and therefore have a partial or vapour pressure of 0.023 atm or about 2,300 Pa, which happens to be the saturation vapour

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pressure of air at 20 C. If you try to add more moisture to the air under these conditions, it will condense out as liquid. The term condensation is probably most often abused when it’s immediately preceded by the word ‘interstitial’. I will not discuss the pros and cons of the Glaser method or EN 13788 here but would encourage you to read about this if you have not done so already. This approach is based on the concept of vapour flux, analogous to the more intuitive heat flux. Apply a higher temperature (or vapour pressure) to one side of a material, and heat (or water vapour) will diffuse though it at a rate dictated by the resistivity of the material and its thickness. It’s essential to differentiate between this process and the movement of bulk air around or through a material – this is also important and often problematic, but it is fundamentally different to diffusion. Therefore the simple ‘cooling air down’ definition doesn’t help here, and we must think in terms of vapour pressure. If vapour (or heat) is diffusing through a wall, driven by a vapour pressure (or temperature) differential, and it encounters a higher resistance – a piece of glass say (or insulation in the analogy), there is a pile-up. There’s still the differential, so the vapour or heat ‘wants’ to move from one side to the other, but it gets stuck. At this interface the vapour pressure increases as more vapour tries to move through, until the vapour pressure at the interface approaches that inside, reducing and ultimately (in theory) cancelling out the vapour pressure differential. But if this location is cooler than inside, because of some insulation, the vapour pressure can exceed the local saturation pressure before it cancels out the pressure to the inside, and water will condense out of the air onto the most convenient nearby thing. This is why conventional design would have us avoid putting impervious (highly vapour resistant) barriers on the cold side of our insulation. A common and not entirely correct secondary conclusion is that we should instead, always have something impervious on the warm side of the insulation. I agree with the first statement to a much greater degree than the second one. So now we have an understanding of ‘classical’ condensation and its interstitial variety. Why would I say that I don’t generally concern myself about it? Well, for one thing there’s enough understanding out there to

avoid this in most cases. I can of course provide an ‘interstitial check’ if you insist on calling it that, but the sort of problems I’m usually asked to investigate are much more interesting. As a very general rule of thumb, mould growth can initiate at about 80% RH, and timber decay at 95% or so. Convention suggests that 80 and 95 are less than 100, indicating that a building can in principle go mouldy and rot away without ever experiencing a drop of condensation. Finally, and most complex is the reason (or rather one of them) that also renders EN 13788 unsuitable in many circumstances. Porous materials exhibit much, much more complex behaviour with respect to moisture than the idealised materials mentioned above. Solid metals, sheet glass and many membrane products for example can be reasonably accurately represented in simple terms, but the majority of materials we build with cannot, to a greater or lesser degree. This is because they are somewhat porous, and somewhat hygroscopic. Hygroscopic materials have an affinity for moisture, which will bind to them across the spectrum of relative humidity. This means that as vapour pressure increases, these materials will absorb moisture, moderating the increase in humidity. If materials such as brick and plaster are present under these conditions they will more often than not absorb moisture fast enough to avoid condensation as you might see on the side of your beer bottle. Students of building physics may (correctly) point out that there is indeed condensation of a different type – capillary condensation, but this is a more complex process than this column allows (being based on the ‘lies to children’ type of simplifications necessary to meet the word count). So as with many things, when it comes to condensation in real buildings, I must deploy one of my most over-used expressions, or simply point to the phrase on my T-shirt: I think you’ll find its more complicated than that. n

Toby Cambray is a founding director at Greengauge and leads the building physics team. He is an engineer intrigued by how buildings work and how they fail, and uses a variety of methods to understand these processes.

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