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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

BIG TIME

Issue 31 £3.95 UK EDITION

UK’s largest passive scheme comes to Camden

Passive endurance


How well are the oldest passive houses faring?

Steeply sustainable


Passive design triumph on impossible site


EDITOR’S LETTER

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

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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.co.uk

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

Oisin Hart oisin@passivehouseplus.ie

Art Director

Lauren Colley lauren@passivehouseplus.ie

Design

Aoife O’Hara aoife@evekudesign.com | evekudesign.com

Contributors

Toby Cambray Greengauge Building Energy Consultants | Stuart Laughton Nilan UK | Marc Ó’Riain, doctor of architecture | Peter Rickaby energy & sustainability consultant | Richard Tibenham Greenlite Energy Assessors | David W Smith journalist

Print

EDITOR’S LETTER

editor’s letter A

s an Irish publisher of a magazine for the UK market, I’ve been reluctant to offer my tuppence worth on the B word these past few years. It goes without saying that many of the readers who may be most responsive to a magazine about sustainable building likely fall into the remain rather than leave camp – the old school libertarian streak in the green movement notwithstanding. But our interest has always been to reach as many people as possible, and to convince them to build quality, healthy, low energy, comfortable buildings that people of any political persuasion would want to live in – and buildings that tread lightly on the earth. Frankly the environmental crises we face are so profound that we can’t afford to act in a partisan way. It may surprise you to know that, when we were rebranding our former Irish sustainable building magazine and entering the UK market, British Euroscepticism was a consideration. When we came to the conclusions that the principles underpinning passive house should be treated as essential to sustainable building, and that this should be reflected in our brand, we were presented with a dilemma. Although the standard originated in Germany, with the Teutonic moniker of passivhaus, even the founders of the standard choose the term passive house in their English-language communications. Passive house was the term that gained acceptance in Ireland, so it was something of a surprise to us that passivhaus was tending to dominate in the UK – and supported by very good reasons. But we were aware of polling at the time, in 2011 and 2012, showing that a Brexit referendum would be close run, and we felt that an Irish publisher with a German name might be a bridge too far for some readers — even if others may specifically identify with it more for those reasons. From my perspective – without considering what impact Britain’s torturous EU

ISSUE 31 withdrawal machinations may have on our business over the coming years – Brexit is a tragic distraction. We are facing such an urgent and immense challenge in the climate crisis that we can’t afford to have Britain focusing so much energy, time and resources on a matter which, with the greatest of respect, pales in significance compared to the fight to keep the world our children inherit fit to inhabit. It is bitterly ironic that, at a time when the need for a collective, global approach has never been more pressing in peace time – or perhaps at any time – countries such as Britain and the USA should instead turn inwards. This is not to say that bold climate action isn’t happening in the UK – there are positive signs of local authorities taking matters into their hands, and of the Welsh and Scottish assemblies taking more progressive approaches, along with positive political rhetoric from Westminster in terms of plans for significant long-term reductions. But then setting ambitious targets that this government will not be in place to answer for – or the next government, or the one after that – smacks of cynicism, in the absence of a clear plan that includes profound short and medium-term change too. But the contrast from this side of the Irish Sea is pretty stark. Ireland has historically aligned our building regulations with the UK. No more. From November, all new homes in Ireland will have to meet the nearly zero energy building (NZEB) standard, a target that sails very close to passive house, with additional renewable energy generation. This is an EU requirement, so every EU member state is bound to take similar action. And while the UK has pledged to implement all EU policy up until the point at which it leaves, the UK government’s shameful inaction on NZEB tells a different story. Regards, The editor

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

Cover

Phase one of Agar Grove, Camden Photo by Jack Hobhouse/Architype

Publisher’s circulation statement: Passive House Plus (UK edition) has a print run of 11,000 copies, posted to architects, clients, contractors & engineers. This includes the members of the Passivhaus Trust, the AECB & the Green Register of Construction Professionals, as well as thousands of key specifiers involved in current & forthcoming sustainable building projects. 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 10,046 for the period 01/07/17 to 30/06/18.

About

Passive House Plus is an official partner magazine of The Association for Environment Conscious Building, The International Passive House Assocation and The Passivhaus Trust.

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CONTENTS

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CONTENTS COVER STORY

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24

34

06

INTERNATIONAL

12

NEWS

19

COMMENT

24

CASE STUDIES

This issue features a low energy community centre in a mountainous region of Austria.

Deep concerns over quality of office-to-flat conversions, more councils embrace the passive house standard, and first ever passive house project nominated for the Stirling Prize.

Dr Marc Ă“ Riain looks at how the design approaches of architects and engineers diverged in the middle of the 20th century; Dr Peter Rickaby says he has never been more optimistic about the prospects for a sustainable built environment; and Richard Tibenham of Greenlite Energy Assessors explains why two particular buildings should serve as a warning to the whole construction sector.

COVER STORY: Big Time UK’s largest passive scheme comes to Camden

The first phase of the hugely ambitious Agar Grove redevelopment in Camden was finished in April 2018. Not only is it the largest passive house scheme in the UK to date, it also aims to be a model for sustainable urban regeneration and for creating liveable spaces at the heart of our cities.

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64

62 34

Strong & Stable East Sussex home with a striking farmyard-inspired design

While this striking new larch-clad home in rural East Sussex ultimately received the backing of the local planners, there was just one catch: it had to meet the passive house standard before its owners could move in.

42

52

64

Steeply Sustainable Low carbon passive design triumph on impossible Cork site

The unique split-level, wedge-shaped plan of this striking and award-winning new passive house in Cork isn’t just for show — it is a carefully thoughtout response to an extremely challenging site, and an example of how great architecture can create beautiful, sustainable buildings in even the most unlikely of spaces, and with a fraction of the upfront carbon costs of traditional build methods.

Low energy garden building unmoved by weather extremes

A new garden office and show room provides a showcase for how heat pump and heat recovery ventilation technology — when combined with a fabric-first approach to construction — can provide a consistently comfortable and healthy indoor environment, no matter what the weather outside.

INSIGHT Passive Resistance How are the first passive houses faring today?

One of the most common questions asked of passive buildings is how they will perform in the long-term — will the building still be airtight in 20 years, and will the heat recovery ventilation still be working? Recent testing and evaluation of passive houses built in the 1990s and 2000s sheds new and convincing light on these questions.

68

Developing Story Life inside in Ireland’s largest low energy housing scheme

Over the last decade, Cosgrave Developments have set about building a new neighbourhood near the south Dublin seaside town of Dún Laoghaire. Honey Park and Cualanor are two adjacent schemes comprising nearly 2,000 low energy homes, one of which houses this magazine’s editor, who has found a scheme with green credentials that go far beyond a good energy rating.

CONTENTS

74

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

What can space travel tell us about building science?

In the first instalment of his new column on building physics, Toby Cambray, co-founder of Greengauge Building Energy Consultants, takes a look at some similarities and differences between rocket science and building science.

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AUSTRIA

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

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INTERNATIONAL

Photos: Christian Flatscher

PASSI V E & E C O BU IL D S F R O M AR OUND THE WO RL D

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IN BRIEF Building: 615 sqm community centre Architect: Johannes Nägele Method: Concrete core with timber frame shell Standard: Low energy new build with passive house components

INNERBRAZ COMMUNITY CENTRE, BLUDENZ, AUSTRIA

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hen the villagers of Innerbraz in the mountainous Bludenz district of eastern Austria wanted to inject new life into their village, they launched an architectural competition for the design of a new community centre. Ten proposals were entered, but it was local architect Johannes Nägele’s striking-yet-sensitive design that won the day. Finished in 2017, the new centre now beautifully contrasts and compliments the more traditional surrounding buildings under the snowy peaks of the Vorarlberg Alps. The building houses three functions: on the ground floor are the new community offices, set at street level to make them open and accessible to local residents. At basement level is a new childcare facility, with access to a sheltered outdoor playground, while on the top floor there is a large, acoustically isolated rehearsal space for the local music society. Set beside the existing kindergarten and local schools, the placement of the new community centre also creates new and extended outdoor spaces for pupils to share. There is also a new public courtyard

facing the road, with a covered entrance where locals waiting for the bus can shelter from bad weather. Outside, the town hall’s striking facade is clad with silver fir, a tree native to these alpine regions. Structurally, it features an inner load-bearing concrete frame with an outer, airtight (0.56 ACH) prefabricated timber shell, insulated with sheep wool. Both the interior walls and furniture are clad with untreated, brushed wooden surfaces from local fir forests too. “They can still smell the silver fir inside,” architect Johannes Nägele says. Speaking to Passive House Plus, Nägele said that the various functions of the building mean it has become a lively village centre, and he says its users are particularly happy with the excellent indoor air quality provided by the controlled ventilation system. Space heating demand is very low too (10 kWh/m2/ yr), and is met by the region’s district heating system, which is fed with locally grown wood chips. All in all, Nägele says the new town hall has helped lead to the “revitalisation of the village”.

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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

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NEWS

Office-to-flat conversions “deeply worrying” Rights allowing the conversion of commercial buildings into dwellings, without planning permission, are potentially creating unhealthy living conditions.

Words by Kate de Selincourt

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ermitted development rights (PDR) allowing office buildings to be converted to dwellings without the need for planning permission have led to a “deeply worrying” situation with tiny one-room flats, in unsuitable locations, being used as temporary accommodation for families with children, posing a high risk to the children’s health. The UK government is now considering a dramatic extension of permitted development rights, to allow new-build dwellings to be erected on the site of demolished offices, also without the need to seek planning permission. “We intend to continue to consider the design of a permitted development right to allow commercial buildings to be demolished and replaced with homes,” the Ministry of Housing said in a consultation response earlier this year. In August, the Children’s Commissioner published a report that highlighted the plight of families housed in shipping containers. The report was equally damning of conditions in office-to-residential conversions, which the commissioner called “deeply worrying”. “There is high demand [from local authorities] for temporary accommodation in these blocks,” the commissioner found. In the past three years more than 42,000 homes have been converted from offices under the PDR provision. Dwellings measuring as little as 18 square metres “may be shared by a whole family, with parents and children living and sleeping in the same single room also containing their cooking facilities,” the commissioner says. Others are even smaller. The Royal Institute of Chartered Surveyors (RICS) found examples measuring just 15 or 16 m2, while Levitt Bernstein reports some ‘double studios’ of 14.7 m2. One dwelling has been reported to be only 9 m2. By contrast, the nationally described space standard specifies that self-contained bedsits and studio flats should be at least 30 m2, while a one-bedroom flat for two should be at least 50 m2. Issues reported in PDR conversions include overcrowding, complete lack of children’s play space (inside or outside) and dangerous locations on industrial estates. There are also serious concerns relating to ventilation, over-

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heating and fire safety. Overcrowding is possibly the most serious health risk to occupants. The Children’s Commissioner reports instances of infants being so restricted in their opportunities to crawl and play that their motor development appeared delayed. Small, single aspect spaces are hard to ventilate effectively and quietly, even when not overcrowded, and at such high occupant densities the challenge is even greater. While the dwellings under PDR are meant to be compliant with building regulations, building physics consultant Toby Cambray of Greengauge points out that, “Part F [the section of the building regulations that covers ventilation] was not designed to cope with this. It was designed to work with separate rooms, and much more space.” “While it is possible to engineer your way around most problems if you spend enough money, a lot of these developments seem to be driven primarily by a desire to make a profit, and I would be very surprised if they all have effective ventilation installed.” ‘Living in an oven’ Occupants of PDR dwellings have also reported severe overheating: one described it as like “living in an oven” and said they “started to feel faint and unwell”. “It is very difficult if not impossible to achieve a good level of natural ventilation in a small, single aspect space,” Cambray says. “With a new build you do at least have control over the design of windows, but with some of these it looks like they haven’t replaced the windows, and in many offices these are designed not to open – which would be bonkers for a dwelling.” The research by RICS confirmed that some of the conversions had seen “barely any changes to the building”. They found that in many PDR conversions windows only opened a small amount, or even not at all. Levitt Bernstein also reports a proposed conversion of what appears to be a light industrial unit into 15 dwellings, where seven of the flats would have no natural light whatsoever. The local council attempted to block this conversion, but the inspector overturned the

(above) Newbury House in Redbridge was converted from offices to residential. Its plans show studios as small as 13 m2, and the majority of its flats are single aspect. Photo by Levitt Bernstein

refusal on appeal, because the objection to lack of windows fell outside the legally allowable grounds for refusal. Not everyone, however, is unhappy about the PDR provisions. RICS reports the words of a private sector planning consultant, who expressed concern about the way PDR enables developers to avoid any obligation to provide affordable housing. The consultant told the RICS interviewer: “From my client’s perspective it’s fantastic… one that I’ve just mentioned, that Christmas, I got a big hamper from him…because he had saved himself millions [on the affordable housing]. Really, you’re getting away with murder as far as this is concerned, but they’re playing to the rules.” In his review of the planning system for the Town and Country Planning Association, former minister Nick Raynsford wrote: “Given the government commitment to expand permitted development, this … must now be seen as the government’s potential model for the future of the [planning] system.” Passive House Plus asked the Ministry of Housing, Communities & Local Government if this was in fact the case. However, the ministry’s reply only referred to government spending to address homelessness, and our question about deregulation of planning was not answered. A fully referenced version of this article is available at www.passivehouseplus.co.uk n


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UK Passivhaus Conference comes to Salford

NEWS

More councils adopt passive house standard

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his year’s UK Passivhaus Conference will take place on Tuesday, 29 October in Salford, Manchester. Among the speakers at the event, the Committee on Climate Change’s Jenny Hill will set the scene on the UK’s 2030 carbon targets, and what role buildings must play in the meeting them. Organised by the Passivhaus Trust, the conference will also hear international experience from municipal authorities delivering passive house at regional scale, while the trust’s research and policy director John Palmer will outline a roadmap for scaling up passive house delivery until 2030. The conference will also explore a range of exciting projects that are paving the way to mainstreaming the passive house standard. These include the Erne Campus for South West College in County Fermanagh, the Agar Grove regeneration project in London, and a new passive house certified hospital in Frankfurt. New interactive workshops at the conference will focus on the challenge of delivering passive house training and skills, and on stimulating demand. There will also be workshops looking at the role of buildings in decarbonising city regions, and on industrialising the process of delivering the passive house standard. 
 The conference is supported by silver sponsor Kingspan and bronze sponsors Ecological Building Systems, Econekt and Munster Joinery. The sponsors will also be joining an exhibition of passive house products and services, alongside CVC Direct, Ecology Building Society, Green Building Store, ICF Supplies, LAMILUX UK, MagmaTech, Nilan UK, PYC Group, SIGA & Willmott Dixon. The conference will take place at The Lowry on the quays in Salford. To register or for more information see www.ukphc.org. • (above) Citu development director Jonathan Wilson speaking about the Leeds Climate Innovation District, at a packed-out UK Passivhaus Conference 2018.

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ocal authorities across the UK are starting to embrace the passive house standard by formally encouraging its use in their planning policies and local area plans. This follows confirmation from the government last year that councils were entitled to set higher building energy efficiency standards locally than is mandated by Part L of the building regulations. Fareham Borough Council has adopted a passive house policy for its Welborne Garden Village project near the M27, outside Southampton. The policy states that 10% dwellings on the site should be built to the passive house standard “unless it can be demonstrated to be unviable by means of a financial assessment”. According to the council, Welborne will be a “a self-contained Garden Village with thriving new district and local centres, new jobs, schools, facilities, shops and community facilities” connected by footpaths, cycle lanes and new bus services, with a large central park at its heart. Welborne is expected to see the construction of around 6,000 new homes over the next 25 years, meaning it could become a significant hub of passive house construction. Bristol City Council’s new draft local area plan also explicitly encourages the use of the passive house standard, and states that passive-certified buildings will be exempt from meeting other local authority targets relating to carbon emissions and renewable energy, as well as being exempt from the requirement to submit an energy strategy

at planning stage. Such exemptions are an implicit endorsement of the passive house standard’s inherent ability to deliver significantly reduced energy consumption and carbon emissions in buildings, without the need for extra verifications or assessments. Glasgow City Council meanwhile, which recently completed a five-storey passivecertified social housing tower, has now included the standard in a suite of options for meeting its local sustainable housing targets. It has also made certified passive houses exempt from its requirement for renewable energy generation in new developments. These tentative moves follow on from the pioneering work of Exeter City Council, who apply the passive house standard to all new council-built dwellings, and Norwich City Council, which is targeting the construction of 1,000 passive house homes over the next decade, and is already a significant centre of UK passive house construction. Further councils across the UK are expected to follow suit, now that over 200 local authorities across the country have declared climate emergencies. Passive House Plus is currently working with the Passivhaus Trust to gather information on local authorities that have adopted policies that support or mandate the passive house standard. If you know of any other such policies, email us on info@passivehouseplus.ie. (above) Artist’s illustration of Welborne Garden Village.

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NEWS

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‘Bottom up’ approach can kick-start retrofit, report finds

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new report has advocated a 'bottom-up' approach as an effective way to deliver the deep retrofit of the UK's building stock at scale. Manchester-based social enterprise Carbon Co-op published its recommendations for kick-starting the market for domestic, owner-occupier retrofit in the UK at the Community Energy Conference on 22 June. These included the use of trusted community energy intermediaries, on-site training for local contractors, and engaging householders through "innovative community-based social marketing campaigns". Funded by the Department of Business, the co-op’s People Powered Retrofit project has spent six months testing a new retrofit service offer, gauging householder interest, understanding the capacity of the local supply chain, and assessing contractor training needs. The conclusions of this research have now been published in the new report, which is available to read at www.tinyurl. com/ppretrofit. Among its key recommendations are: • Taking a local approach and engaging with householders and existing supply chain networks via a trusted community intermediary. • Recognising that it's not all about payback. Client purchasing decisions are influenced by a number of interlinked issues such as quality, disruption, potential health benefits and wider social values. • The delivery of owner-occupier retrofit is a complex service, resistant to automation and purely technological approaches. It’s about people and clients, not housing archetypes. • Creating a local retrofit market requires an integrated, neighbourhood-scale local economic development approach from local authorities, utilising existing networks and partnerships. • Historic forms of local authority lending should be repurposed to secure wider social value from new local retrofit markets. “Extinction Rebellion, the schools strike and ambitious local and government carbon reduction targets show that finding new, effective ways to de-carbonise our housing is an absolute priority," said People Powered Retrofit project manager Jonathan Atkinson. "Our new report demonstrates a clear service offer that can be delivered at a local scale, involving community organisations, local authorities and the existing, high quality construction sector all working together.” Over the next two years, the People Powered Retrofit service will be piloted in two Greater Manchester neighbourhoods: Levenshulme, South Manchester and Halliwell, Bolton, with retrofit works expected to commence this autumn. •

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Alliance for Sustainable Building Products opens awards for entries

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he Alliance for Sustainable Building Products (ASBP) has announced that the ASBP Awards 2020 are now open for entries. The awards programme recognises construction projects that exemplify excellence in sustainability through their products, design and delivery. Submissions are judged by members of the ASBP board, who have expertise from across the construction industry, and assessed against the ASBP’s ‘six pillars of sustainable construction’: health and well-being, resource efficiency, whole-life carbon, ethics and transparency, technical performance, and social value. The ASBP said that last year’s inaugural awards were a huge success, and that the judges found the assessment process “uplifting and inspiring in equal measure”. The six shortlisted projects from the ASBP Awards 2019 are featured as case studies on www.asbp.org.uk. This year, the ASBP Awards judges are looking for exemplary sustainable building projects with a particular focus on: • building products essential to the success of the project, with evidence of their performance; • measured performance data for the project and explanation of what the results show; • lessons learned from the project and what could be done differently; • replicability/buildability – design and construction approaches utilised on the project that have potential for replicability and adoption at scale.

The ASBP Awards 2020 are free to enter and open to construction projects, both new-build and retrofit, from across the UK built environment sector that were completed by July 2019. Interested entrants can see full entry criteria, FAQs and submit their project for free until 30 September 2019 via the ASBP website. Judging will take place in October 2019 with the shortlisted projects being announced in November 2019. Shortlisted entrants will be invited to present at the ASBP’s fourth Healthy Buildings Conference and Expo, which is set to take place on Thursday 27 February 2020 at Amnesty International's HQ in London. “The shortlisting process last year was extraordinarily difficult due to the exceptional quality of the projects entered. We look forward to hearing about many more inspiring, sustainable building projects submitted for the ASBP Awards 2020,” said Gary Newman of the ASBP. • (above) Bowman’s Lea, a deep retrofit to a 1978 mid-terrace townhouse by Arboreal Architecture was the overall winner of the 2019 ASBP Awards. The project – the first step-by-step certified Enerphit project in the UK – was praised for its resource efficient approach, with cork insulation offcuts used to insulate a whole room.


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NEWS

Architype launch ‘performance gap’ consultancy

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ollowing the firm’s recent award for the Sustainable Practice of the Year at June’s AJ100 awards, leading passive house design firm Architype has announced the launch of PERFORM+, a new building performance and environmental consultancy. The service is designed to help minimise the ‘performance gap’ between how buildings are designed and how they operate and optimise their real-world performance. “Buildings that perform as predicted at design stage are all too rare; that’s not good enough for us,” said Architype’s managing director, Jonathan Hines. Architype said that the core purpose of PERFORM+ as an environmental consultancy service is to help clients to

get the best operational results from their buildings. The firm will work at design stage, and with existing buildings, to ensure long-term performance. The consultancy will offer a menu of 20 unique services that tackle five key issues of sustainable design, namely: making buildings work, energy performance, healthy buildings, cutting carbon, and aftercare. When it comes to delivering advice on existing buildings, Architype said it will offer clients a “bold and innovative approach to consultancy fees”. A statement from the firm read: “So confident are Architype in their ability to improve the energy consumption of existing buildings, the practice can offer clients a reduced fee up-front, with an agreement to charge a

proportion of the money saved by the client per annum on energy costs.” The service will work in synergy with the practice’s architectural services, which will continue to be the core focus of Architype’s practice. “We go beyond quick fix solutions, offering a holistic approach to solving both specific and complex problems,” said Hines. “Our advice is not an isolated stand-alone environmental consultancy but is underpinned by decades of experience as leading sustainable architects. Time and again we have been able to achieve major improvements in the performance of building for clients. Clients see this as great value for money.” For more information see www.architype.co.uk/perform. •

Greenbuild Europe 2020 coming to Ireland T

he third annual Greenbuild Europe conference will be held in Dublin on 24-25 March 2020, at the Croke Park conference centre. The event, hosted by the US Green Building Council (USGBC), brings together green building leaders from throughout Europe, and celebrates the industry’s accomplishments in creating a more sustainable built environment, and a better quality of life for all. “Europe is at the forefront of green building,” said Mahesh Ramanujam, president and CEO of the USGBC. “With Europe’s remarkable leadership, Dublin, Ireland, is the perfect location for Greenbuild Europe as we work toward our

vision of green buildings for everyone.” Greenbuild Europe will feature sessions covering all aspects of sustainable design, construction and operations for buildings and communities, including their impact on people, the environment and the economy. Greenbuild attendees will learn about LEED v4 and v4.1, building performance, energy efficiency, codes, market trends, health and wellbeing, the business case for green building and more. Other topics at Greenbuild Europe will include communities and cities, building performance and smart buildings, codes and certification, and European market trends. USGBC will partner with the Irish Green

Building Council (IGBC) for the event. “We are delighted to welcome Greenbuild to Dublin as a chance to showcase the great work that has been done in Ireland,” said Pat Barry, CEO, IGBC. “With action on climate change now a top priority for the Irish government, Greenbuild Europe will showcase solutions from the building sector. We are looking forward to sharing ideas and best practice in green building with professionals from Europe and around the world.” Registration for Greenbuild Europe will open in autumn 2019. Sponsorship opportunities are currently available. See greenbuild.usgbc.org/europe for more information. •

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Norwich passive house project nominated for Stirling Prize

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he Goldsmith Street development in Norwich has become both the first social housing scheme and the first passive house certified project to be nominated for the Stirling Prize, British architecture’s most prestigious award. Goldsmith Street is a development of 105 passive house certified new homes for Norwich City Council, designed by architects Mikhail Riches with Cathy Hawley. “This project is a culmination of 11 years commitment and courage by our client, Norwich City Council,” read a statement from Mikhail Riches. “We are absolutely thrilled to see a 100% social housing scheme on the Stirling Prize shortlist. “We work very hard to make beautiful architecture that is socially and environ-

mentally conscious, here we had a client that pushed us further to achieve certified passive house at scale. The purpose of our practice is to create buildings people love. We hope people will love living here.” Meanwhile the adjudication panel for the Stirling Prize said of Goldsmith Street: “It captures the spirit of a very special place. A coherent visual field that communicated the best of enlightened modern domestic European architecture from the outset.” The panel said that the development manages to be dense but not oppressive, with streets that feel owned “by pedestrians rather than cars”, and a high standard of workmanship and impressively

Photo by Tim Crocker

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NEWS

high-spec interiors. “Bringing the reduced energy consumption associated with passive house to mass housing is a great achievement, and one that has taken a large amount of effort and care by the architects. This is an exemplary project.” Other key members of the project team included contractor RG Carter, M&E engineer Greengauge, passive house designers WARM and clerk of works Enhabit. The winner of this year’s award will be announced on 8 October at a ceremony at the Roundhouse in London. • (above) The Stirling Prize nominated Goldsmith Street scheme in Norwich.

New overheating tool for homes launched

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he Good Homes Alliance (GHA) has announced the launch of a new software tool and accompanying guidance which aims to help planners and design teams identify and mitigate overheating risks in new homes. The tool is intended for use at the early design stages of new residential development in order to identify key factors contributing to overheating risk, and possible mitigation measures. The alliance said that the tool is informed by existing guidance, current research and feedback from occupied schemes. It covers early design decisions as well as site-related issues which can impact on overheating risk. The tool consists of a scoresheet containing 14 questions with accompanying guidance notes for each question. The guidance

16 | passivehouseplus.co.uk | issue 31

for the tool states that it “is not meant to provide a detailed assessment, but instead to sit between existing high-level guidance, often aimed at policy makers, and detailed calculation and modelling tools, often aimed at architects and engineers.” The alliance recommends that the tool be “used collaboratively to prompt dialogue between project teams and local authorities, with disciplines including architecture, building services engineering, acoustics, and environmental health, among others.” To assist with the use and uptake of the tool, the Good Homes Alliance and the research project team is developing a number of training packages for local authorities and design teams, including half-day masterclass tutorials and bespoke in-house training

workshops using real case studies. “The great thing about the GHA overheating tool is that it is very simple to use and so helps architects and builders consider issues of natural light, ventilation and shading at an early stage of a project," said Mick Schou Rasmussen, managing director of VELUX, one of the sponsors of the project. "Overheating is a serious issue, and despite the usual assumptions about poor British weather, experts are warning us the housing stock may not suitably protect us against rising temperatures and we commend GHA’s efforts to bring the tool into use.” For more information, please see www. goodhomes.org.uk/overheating-in-newhomes. •


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

NEWS

China hosting passive house conference

A rendering of the Gaobeidian district, which will be the largest passive house scheme in the world.

T

he 23rd annual International Passive House Conference takes place outside of Europe for the first time ever this year, with the Chinese city of Gaobeidian hosting the event on 9 to 11 October. This year’s conference was rescheduled after originally being set for 21 and 22 September. Gaobeidian is about 100 km south of Beijing, and the construction of a passive house district comprising over 20 high-rise buildings is currently underway in the city. Once complete, this will be the largest residential passive house development in the world. "China is the country with the most construction work going on at the moment, and this is not being done sustainably at present. This means that we must do our utmost to ensure that the development towards sustainable construction also

advances in China,” said Dr Wolfgang Feist, founder of the Passive House Institute. The theme of this year’s conference is ‘passive house worldwide’ and the German environmental scientist Ernst Ulrich will deliver the keynote speech. A series of more than 20 lectures will take place on 9 and 10 October (Wednesday and Thursday). Two of these presentations will focus on passive house projects in China, while others will look at energy efficient retrofits from around the world. Working groups will also examine topics including passive house projects in hot climates, kitchen ventilation systems, airtightness in high-rise buildings, as well as the design tools PHPP and designPH. All presentations will be held in English or Chinese and simultaneously be translated

into the other language. Other workshops will focus on airtightness, energy balance at the district level, energy efficient hot water systems, cooling and dehumidification, calculation of thermal bridges, ventilation systems and windows. A two-day “train-the-trainer” workshop will be geared towards those organising courses for certified passive house designers and tradespersons. Participants can also choose between three passive house excursions: a visit to the Gaobeidian passive house district, passive house projects in the capital Beijing, or a passive house office complex in Zhuzhou, which is about 30 kilometres from Gaobeidian. For more information about the event and logistics of attending see www.passivehouseconference.org. •

World NZEB Forum comes to Dublin in November

M

inister for finance Pascal Donohoe TD announced the World Nearly Zero Energy Building (NZEB) Forum at government buildings recently, to be held in Dún Laoghaire on 13-14 November. The conference takes place just two weeks after NZEB becomes mandatory in Ireland for all domestic construction, and conference hosts NZEB Ireland are reporting substantial interest in the event from the design and construction community. A stellar line-up of speakers from home and abroad has been prepared by NZEB Ireland and the event will run over two days, with optional site visits and workshops on day one and the main event on day two. Case studies will form the core of the conference, from both residential and commercial sectors, and including two dedicated tracks on the retrofit challenge. The conference is supported by Dún LaoghaireRathdown County Council with lead sponsorship by Kingspan. Further details on the NZEB event of the year can be found at www.worldnzebforum2019.com. •

(above) Pictured at the official announcement of the World NZEB Forum at government buildings are (l-r) Dún Laoghaire-Rathdown county architect Andrée Dargan; minister for finance Pascal Donohoe; and former Dún Laoghaire-Rathdown County Council cathaoirleach Cllr Ossian Smyth.

ph+ | news | 17


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COLUMN

MARC Ó RIAIN

The schism in solar energy In his latest column on the evolution of solar energy, Dr Marc Ó Riain looks at how the design approaches of architects and engineers diverged in the middle of the century.

A

rchitecture and engineering can often seem like different worlds, alien from each other, with different values, priorities and cultures. In the mid-late 1950s, architectural and engineering interests in solar energy and solar housing diverged, only to recombine in late 1973 to respond to the first oil crisis. The falling price of oil, gas and electricity through the late 1950s in the US undermined the demand for existing renewable technologies. The arrival of International movement architects from Europe displaced indigenous architects and their American modern style. Mies van der Rohe’s Farnsworth House would trump Lloyd Wright’s Solar Hemicycle. The ‘Case Study’ house program in California had created sustainable models for modest modern living but failed to achieve mass market scalability. By 1950, architects in the US had established the principles of good solar house design and this was promoted by manufacturers like Libby Owens Ford in their publication of modern solar house designs for nearly every US state. Engineers like Telkes and architects like Raymond had designed an innovative house to harness solar gain through windows, storing it in phase-change heat bins (Dover House). But consumer demand had shifted toward electricity, with most households installing refrigeration, washing machines, water heaters and 250 million mass-produced air

active engineering technologies like fluorescent lighting, air conditioning and elevators which would allow starkly rectangular, deep plan and unshaded glass slabs to be designed, mimicking Corbusier and Sant’Elia’s futurist visions. These engineering solutions freed the architect from environmental performance concerns. “All precepts for climatic compensation through structure and form are rendered obsolete” (Banham, 1969). Therefore, architects did not need to concern themselves with engineering trivialities — systems were to be contained, hidden, enclosed and accommodated within the formal expression.

The first building to have a solar array was a remote Japanese lighthouse in 1963.

conditioning units by 1954. Electricity - not heat - would be the focus of future research. MIT’s 1950 conference on ‘space heating with solar energy’ demonstrated that a schism existed between architectural and engineering approaches to this changing market. Denzer (‘The Solar House’, 2013) argues that architects had focused on the psychological, aesthetic and typological effects of living in and designing an optimal house whilst the engineers were concerned with data and performance issues. Supporting this in the subsequent decade, engineers would take a different path from architects in exploring solar voltaic solutions to building energy. Architectural styles would be freed by

Meanwhile, the engineers shifted focus toward alternative active solar research. In 1883, American inventor Charles Fritts made a 1% efficient solar selenium cell. In 1940, Russell Shoemaker Ohl at Bell Labs discovered that a silicone sample with different levels of impurities on either side conducted current when it was exposed to light, but again was only 1% efficient. In 1953, two chemists at Bell Labs dipped a piece of silicon containing gallium impurities into lithium and shined a light on it, producing an electrical current. Unfortunately, the gallium-lithium combination degraded too quickly at room temperature, so they shifted to a boron-arsenic silicon

cell and linked them together into a “solar battery”. In 1954, they demonstrated their 6% efficient solar panel by using it to power a small toy Ferris wheel and a solar powered radio transmitter (APS 2009). By 1957, Hoffman labs had produced an 8% efficient solar cell, 10% by 1959 and an impressive 14% by 1960. The first building to have a solar array was a remote Japanese lighthouse in 1963 with a 242-watt array by Sharp Solar who started mass production of solar cells. Luckily for this emerging technology, this coincided with the initiation of the space race. A solar array of 3,600 solar cells covered most of the Telstar 1 satellite, which was launched in 1962, and produced a tiny 14 watts of power. Although solar PV had commercial applications in the 1960s, cost per watt could not compete with the established nuclear power industry until the 1990s. Building-integrated and roof-mounted photovoltaics only started to be seen in the early 1990s, as costs fell with advances in clean manufacturing. PV therefore was not the technological solution to the oil crisis of 1973. There was little interest in the environment in the late 1960s, and solar architecture had failed to achieve market penetration or market consciousness. Behavioural change and a global economic shock would be the impetus for a sudden geo-political policy and consumer change. In the next issue I will discuss the rise of the environmental movement in the 1960s that will frame this geopolitical fulcrum point. n (above left) Model of the Telstar 1 satellite, which was launched in 1962 and covered in 3,600 solar cells. Photo: Tiia Monto.

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.

ph+ | column | 19


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COLUMN

DR PETER RICKABY

Is it too late for sustainability? Despite the urgency with which radical action is required to transform our built environment, Dr Peter Rickaby says he has never been more optimistic about the possibility of change.

I

t is some time since I have felt as optimistic about the prospects for a sustainable built environment as I have recently. The global campaign of young people led by Greta Thunberg, the response to David Attenborough’s documentaries, and popular support for Extinction Rebellion are encouraging and inspiring. The Committee on Climate Change’s report, the UK government’s ‘Buildings Mission’ to halve the energy use of new buildings and halve the cost of retrofitting existing buildings to the same standard by 2030, and revision of the statutory greenhouse gas emissions target from 80% reduction to net zero by 2050, are all steps in the right direction. As are the opportunities for ambitious reviews of building regulations in England and in Wales, the promotion of quality-assured deep retrofit via the Whole House

The success of the passive house standard and the growing numbers of passive house certified designers are evidence that building and housing professionals are taking sustainability seriously and understand the need to change the way we build. A group of award-winning UK architectural practices have declared that they will lead the drive for sustainable buildings through their Architects Declare petition (www.architectsdeclare.com), after years of domination of our industry by contractors, developers and housebuilders whose main interest has been the bottom line, and many of whom (with some laudable exceptions) have fiercely resisted change. A culture change is needed — organisations must protect not just their own interest (and profits) but also those of their customers and of the public. The new UK domestic retrofit standard PAS 2035 requires

We must stop using concrete, bricks, steel and excessive amounts of glass.

Retrofit competition, and implementation of the Each Home Counts review, TrustMark and the domestic retrofit standard (PAS 2035). In Ireland, the EU’s NZEB (near zero energy buildings) standard is embraced and SEAI’s Deep Retrofit programme is showing the way to a sustainable housing stock. On the other hand, the Trump administration in the US is recalcitrant and irresponsible, UK politicians are obsessively distracted by nonsense, and the devolved governments and local authorities that have declared ‘climate emergencies’ show little understanding of the scope of appropriate response. The UK government supports the expansion of Heathrow Airport, the extraction of oil and gas from beneath the North Sea, and the development of fracking. A friend who monitored action on energy efficiency in housing for over forty years showed that the level of activity simply tracked the international oil price. We have been here before, and hope has quickly been dispelled by a lack of joined-up thinking, the politics of the Middle East, a change of government or even a change of minister. How can we keep sustainability on track this time?

the appointment of a qualified retrofit coordinator for every project and defines part of the Retrofit Coordinator’s role as protecting clients’ interests and the public interest. This provision, when incorporated in an early draft, baffled some members of the steering group whose organisations had for years focussed on deriving profit from government retrofit and fuel poverty programmes, had paid little attention to the health and welfare of householders, and who saw no need to change the way they work. The change required is so far-reaching that it is hard to grasp and can only be sketched out here. We must stop expanding airports. We must stop building city-centre office blocks with huge journey-to-work footprints in the transport sector, and instead re-think working practices using the internet. We must stop building shopping centres surrounded by carparks and continue to re-think retailing around online shopping and efficient delivery. We must co-locate homes and workplaces, schools and recreation within walking distances of each other and on public transport routes. We must deal with fuel poverty because people who live in cold,

damp, mouldy homes are not interested in reducing emissions – they just want to be comfortable. We must make our buildings energy efficient, and healthier. We must eliminate dependence on fossil fuels from our buildings and focus instead on clean electricity. We must stop using concrete, bricks, steel and excessive amounts of glass because they are the most energy intensive building materials imaginable. We must turn most buildings into exporters of energy, to compensate for the protected buildings whose energy demand will be difficult to eliminate without damaging our architectural heritage. We must adopt a whole-life approach to energy use and emissions. We must re-use old buildings or recycle the materials and products from which they are made, and we must design new buildings for easy re-use and/or recycling. None of this is new, but it amounts to a huge challenge. Scientists tell us that time for effective action on climate change is running out. We may already have left it too late, but I suspect that if we fail to rise to the challenge this time our children will not forgive us. n

Dr Peter Rickaby is a semi-retired energy and sustainability consultant who works for the UK Centre for Moisture in Buildings at University College London. He also chairs the BSI Retrofit Standards Task Group, helping to develop retrofit standards for domestic and non-domestic buildings in the UK.

ph+ | column | 21


RICHARD TIBENHAM

COLUMN

How will today’s buildings

perform tomorrow?

Richard Tibenham of Greenlite Energy Assessors says a case of two highly energy-inefficient and ‘hard-totreat’ buildings, built in 2013, should serve as a warning to the whole construction sector.

D

uring his time in office, David Cameron promised a bonfire of the regulations in the building industry. His government even operated a ‘one-in, two-out’ rule, specifying that for every new regulation imposed, two existing regulations had to be removed. Since then, the regulation of energy efficiency in the built environment has roughly plateaued, with the free market and planning authorities taking the lead on energy efficiency and carbon emissions. Consequently, this has given rise to a new phenomenon: that of the new building, often fitted with solar panels and on-site renewable energy generation, which paradoxically eschews energy efficiency in a way that seriously hinders the transition towards a low or zero carbon economy. The consequences of greenwash are letting themselves be known. The term ‘hard-to-treat’ is usually applied to older buildings with solid masonry walls. These require internal or external insulation to improve their thermal efficiency, a disruptive and costly process. But now hard-to-treat characteristics are creeping their way into new and superficially ‘green’ buildings. Recently, I was consulted on the measures necessary to achieve zero carbon operation for two modern buildings, built in 2013 under the building regulations Part L2A 2010. They were equipped with photovoltaic (PV) arrays, as well as reasonably efficient air source heat pump systems. Lighting, including external floodlights, contributed the lion’s share of the site’s energy demand, but internally, space heating was by far the highest demand. Lighting was pretty much the only low hanging fruit that could be addressed. Low wattage LED alternatives offered a low-cost fix, though poor consideration of daylight availability meant that some areas incurred lighting loads year-round, irrespective of lighting efficiency. The client wasn’t quite ready to go knocking large holes in the walls and roof, so taking things further required a bit more head scratching. Despite the heat pumps, wintertime heating energy demand remained high. The buildings’ lightweight steel frames were insulated to minimum standards and incurred high levels of air leakage. The

22 | passivehouseplus.co.uk | issue 31

bolt-on ‘fixes’ of PV and heat pumps where applied as a substitute for form and fabric efficiency. This resulted in two new buildings which just about satisfied the building regulations, yet proved hard to treat so far as further improvements were concerned.

eradicated, and roof pitches and orientations optimised for solar energy generation. In the event, zero carbon operation will likely remain a pipe dream for these buildings and others like them. The UK is sitting on a growing infrastruc-

Hard-to-treat characteristics are creeping their way into new buildings.

In energy efficiency, as in health, prevention is better than cure: maximising efficiency and preventing high energy demand is far better than masking inefficiencies with the short lived cure of renewable energy generation. Concerningly, buildings like this are the norm in the UK. Under the current building regulations, commercial buildings especially all too often adopt a ‘fabric last’ approach — an inversion of the conventional wisdom of fabric first. The falling cost of PV cells has made them a cheap alternative route to compliance, avoiding the riskier business of good airtightness. To boot, a bit of PV on the roof also ticks the boxes for local authority planning policy requirements for renewable energy generation, allowing local councils to make bogus claims about delivering supposedly ‘sustainable growth’. A fabric first approach, integrating form and fabric considerations, offers reduced operational demands during the periods of the year when it most matters, i.e. during the winter, when grid energy demand and carbon intensity are at their highest. The best that can be done for these two buildings is ‘theoretical’ carbon neutrality via a large PV array, providing excess to required energy generation during the summer, yet still incurring high energy demand during the winter. There is only so much summertime demand that can accommodate this dynamic, making it an unsuitable approach for broader city and regional zero carbon aims, unless vast capacities of expensive energy storage is included. If prior considerations had been given to these buildings’ orientation, form and fabric, then heating and lighting loads could have been minimised, cooling loads

ture time bomb, in the form of an unnecessarily inefficient built environment. The industry is crying out for better leadership as consecutive governments’ aversion to better regulation leads to avoidable defects in the UK’s building stock. A report by the Business, Energy and Industrial Strategy Committee (BEIS) states that energy efficiency is the cheapest way to reduce carbon emissions, suggesting that time is hopefully being called on this wasteful endeavor. If we are to avoid carpeting the country in solar and wind farms, then a fabric first approach is needed to ensure that the buildings of today are future proofed for the needs of tomorrow. A fully referenced version of this article is available at www.passivehouseplus.co.uk n


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AGAR GROVE

CASE STUDY

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24 24 | passivehouseplus.co.uk | issue 31


CASE STUDY

AGAR GROVE

BIG TIME

U K ’ S L A R G E S T PA S S I V E SCHEME COMES TO CAMDEN

The first phase of the hugely ambitious Agar Grove redevelopment in Camden was finished in April 2018. Not only is it the largest passive house scheme in the UK to date, it also aims to be a model for sustainable urban regeneration and for creating liveable spaces at the heart of our cities.

Words by John Hearne

£13.50

per month (space heating & hot water, see ‘In detail’ for more) Building: 38-unit, seven-storey apartment block. Concrete frame & cavity wall construction. Completed: April 2018 Location: Camden, London Standard: Passive house certified

A rendering of Agar Grove, with block A at the back right

ph+ | agar grove case study | 25


AGAR GROVE

CASE STUDY

B

ack in early 2012, when Camden Council began talking to the residents of Agar Grove about the proposed redevelopment of their estate, the occupants of one of the blocks – Lulworth Tower – decided to opt out. Unlike the rest of the estate, which was managed by the council, Lulworth was run by a tenant organisation and had an independent management structure. Throughout that year and into 2013, the council continued the consultation phase for the rest of the residents, running events and exhibitions in the estate’s community space. It was following one of these exhibitions that the Lulworth tenants’ organising committee approached the council and asked if they could opt back in. “That was really exciting for us,” says Michelle Christensen, senior development manager at Camden Council. “The success of what they saw going on around them generated a high level of trust. We were delighted to begin looking at options for them.” If you could isolate one factor to account for the success of the redevelopment of Agar Grove in its initial stages, it’s has been communication. There has been a free flow of ideas, expertise and feedback between everyone involved: council, residents, designers, contractor, subcontractors and so on. “Design-and-build contracts don’t normally tend to lend themselves to open dialogue,” says Christensen, “but in Agar Grove, it’s been really essential to making it all work and making it all successful.” Agar Grove is the largest passive house development in the UK to date, though not all of the proposed 493 homes will be certified passive. The aforementioned Lulworth Tower – owing to its size and the high levels of embodied carbon in its concrete structure – will be stripped down and refurbished to a high (though not quite passive) standard.

26 | passivehouseplus.co.uk | issue 31


CASE STUDY

This does not take away from the fact that this project is one of the most ambitious that we have covered in Passive House Plus to date. Urban regeneration To go back to the beginning, the Agar Grove estate was built in the 1960s. As with much of the local authority housing of that era, the rooms were cold, draughty and expensive to heat. Cold bridges abounded, giving rise to significant damp and mould growth issues. They were also too small. “The three-bed units were 69 square metres,” says Christensen, “which is less than London design guide space standards for a two-bed now. Plus, they had odd-shaped, triangular kitchens that you could hardly fit a fridge into.” If the interior layouts were strange, that went double for the external layouts. There were bedrooms at ground floor level and large empty spaces of uncertain function. Surrounded on two sides by railway and

enclosed by a high fence, the whole layout felt defensive and uninviting. “It was completely detached from the streets around it,” says James Woodward of design architects Hawkins Brown. “There was no logical hierarchy between private and public space. There was a huge ball court tucked into a corner of the site, but no one used it; it wasn’t overlooked and didn’t feel safe.” The overall context for the project was Camden’s borough-wide community investment programme, which launched in 2010. This was a systematic analysis of all councilowned assets with a view to building more affordable housing, schools and community facilities, and to invest in the existing housing stock. At the outset, a variety of options were investigated for Agar Grove – including infill development, and partial as well as complete demolition. At the same time, because this would be Camden’s biggest development, the council was determined that it would be in

AGAR GROVE

some way exemplary. Architecture and urban design were key considerations of course, but so too was sustainability. As the various options were explored, passive house became ever more popular, not least because it ticked a number of ancillary boxes. Agar Grove sits at the heart of the borough, close to Camden High Street and Kings Cross Station, and hemmed in by the aforementioned railway. So, it’s noisy. Triple glazing and whole house ventilation would probably be necessary regardless of design methodology. Moreover, fuel poverty is a significant issue for many of the estate’s fixed income residents. There was also the simple fact that quality assurance is intrinsic to the passive house standard. Liveable spaces There were two central challenges on the site. The first relates to density. The existing site had 249 units, which works out at 97 homes per hectare. The new development, once completed, will have almost twice the number of units – 493. As one of the most accessible sites in the borough, and in the context of a wider housing crisis, it was considered necessary to bring housing density more in line with the surrounding area. Understandably this was a sensitive issue for residents. The fact there was – in the end – general acceptance of the idea that everyone would be getting a lot of new neighbours gives you some idea of the level of trust that had been built up during the consultation phase. If this was a difficult pill for the residents to swallow, the second challenge that the design team set itself did a lot to balance things out: to ensure tenants would only have to move once during the build process. The phasing of the scheme means that a new block is built and, once complete, residents move in and the old block is demolished. This ‘single decant’ process has been the guiding force in the sequencing of the project. “It’s quite a complex puzzle,” says Christensen, “because some families get smaller while others get bigger [during the build]. You’re giving everyone this promise early on and you’ve got to make sure you can keep it.” It’s also worth noting that rather than put the development out to tender, Camden Council decided to take on the role of developer. While this model does involve the local authority

There has been a free flow of ideas, expertise and feedback between everyone involved.

Photography: Jack Hobhouse/Architype

ph+ | agar grove case study | 27


AGAR GROVE

CASE STUDY

Solar thermal to meet a proportion of hot water and may generate revenue through the Renewable Heat Incentive

Living Green / Brown roofs provide natural biodiverse habitats for wildlife

Fresh air

Fresh air

Photovoltaic panels generate electricity and may generate revenue through feed-in-tariffs

Central or individual Mechnical ventilation with heat recovery (MVHR) will continually provide fresh air in winter saving on heating energy

Extract air

Balconies and deep window reveals provide solar shading

A continuous airtightness barrier means no cold draughts and negligible heat lost through fresh air provision Fresh air

Fresh air

Extract air

Thick insulation to meet Passivhaus requirements Triple-glazed windows reduce heat loss and provide an acoustic barrier when windows are closed

Large windows provide plenty of daylight

above An illustration which succinctly sums up most of the key sustainability approaches adopted at Agar Grove.

taking on more risk, it facilitates the provision of a higher level of social housing. The planned breakdown is 50% affordable, 50% private, with the latter cross-subsidising the former. The new Agar Grove masterplan is based upon the traditional concept of streets and squares, with an emphasis on buildings which have front doors at street level, creating liveable spaces between them, and allowing people to move across, through and within the site. The overarching desire is to create a place where people want to live, and which contributes positively to the surrounding area. Roadways within the estate are pedestrian and bike-friendly, while parking is only provided for existing cars and is to be phased out over time. “The design has a logical network of streets that you can find your way around without getting lost,” says James Woodward. In most blocks you have street frontage to one side with shared residents’ gardens at the back. “There is now a legible hierarchy between those spaces.” Achieving the desired layout for the site meant that it wasn’t always possible to orientate the dwellings southward for maximum solar gain, however. “That’s been one of the tensions at the centre of the scheme,” he says. “I think if we had oriented everything in the same way, it wouldn’t have worked with the shape of the site and the context of the landscape.” So, while some blocks have an ideal orientation, others do not. But while a southerly aspect lends itself to achieving the passive house standard in the simplest and most economical manner possible, it is technically possible to achieve the standard with any orientation. It can just mean compensating

28 | passivehouseplus.co.uk | issue 31

in other areas — like, for example, using more insulation. By happy chance, the first phase of the project had the north-south orientation favoured by passive house designers. This, says Woodward, has meant that the lessons learned can be applied to subsequent phases, where the orientations will not be quite so favourable. To the same end, the project teams will hold a ‘lessons learned workshop’ at the end of each phase, providing feedback to the designers on which elements of their plans are most challenging to deliver in practice. Phase one Phase one at Agar Grove – now complete – involved the construction of a 38-unit passive certified apartment block, ranging between five and seven storeys high. This was built with a concrete frame with infill blockwork and a thermally broken masonry support system. Ann-Marie Fallon and Robert White of sustainable design specialists Architype (recently worthy winners of the AJ100 Sustainable Architect of the Year) were appointed by the contractor, Hill Partnerships, as delivery architects on phase one. Fallon is also project lead on phase two, which is currently onsite. The adopted nature of the design meant that several amendments had to be made at delivery. At tender stage, Block A was specified to be masonry construction with a 300 mm cavity. However more detailed analysis by Architype using PHPP, the passive house design software, concluded that this cavity could be reduced to 150 mm due to the optimised form factor of the block (very compact at 1.6). “That was a significant optimisation of the design to revert to a more ‘industry accepted’

Forensic review of PHPP requirements is important for the development of passive house at scale. cavity width, and it typifies what we tried to do on the project,” says Fallon. Such forensic review and optimisation of PHPP requirements is important for enabling the development of passive house at scale, making it cheaper and easier to build. For example, the walls on Block A have a U-value of 0.17, above the typical requirement criteria for passive house (0.15), but still comfortable and sufficient to meet the passive house standard when the building — with its optimum orientation and form factor — is taken as a whole. Similarly, Fallon says that the original tender of intent had the airtightness layer on the inside of the wall construction, as would be the typical approach taken on passive house schemes in 2014 when the scheme was initially tendered. “Moving that to the outside was another innovative move by the delivery team. This optimised the speed of the programme and also created a simpler airtightness layer.” A wet plaster parge coat of 12-15 mm thickness was applied to the outer face of the inner leaf of blockwork. This was combined with what Fallon describes as a “robust taping strategy”. In addition, the thermally broken


CASE STUDY

AGAR GROVE

CONSTRUCTION IN PROGRESS

1

2

3

4

5

6

1 A wet plaster parge coat was applied to the outer face of the inner leaf of blockwork as airtightness layer; 2 thermally broken TeploTie cavity ties, post-fixed using an anchor resin in pre-drilled holes, 3 Halfen HIT insulated connections and 4 Schoeck Isokorb connectors all help to minimise thermal bridging; 5 Installation of the Idealcombi Futura+ timber alu-clad triple-glazed windows; 6 airtightness seals at services pipe outlet.

TeploTie cavity ties were post-fixed using an anchor resin in pre-drilled holes. Masonry supports (over 500 in total) were carefully placed and co-ordinated to avoid tears in taping or large penetrations through the parge coat. As Fallon asserts, keeping all of this to the outside meant that the airtightness strategy was kept independent of internal works within the envelope. These elements could progress in parallel without scheduling issues and with the added advantage of reducing the risk of accidental penetrations by subcontractors. Which is not to say that subcontractors were kept out of the loop – far from it. Odran McShane of contractors Hill Partnerships says that subcontractor buy-in was a challenge at first, but ultimately a key factor in the success of the scheme. Once again, it all came back to communication. “Passive house principles were not initially understood by subcontractors,” he says. “We took a number of steps to ensure the education of the workforce. This was achieved through inclusions within subcontractor orders, toolbox talks and physical samples of key airtightness details which were protected and maintained during the course of the build. The physical samples were particularly useful in that they provided a constant reference and benchmark for the subcontractor to refer back to.” Thermal bridging was also a significant challenge on the scheme. Aside from the TeploTies deployed in the cavity, a thermally broken masonry support system was used on the concrete frame. There were over 500 of these supports in total. “On a building of this scale, between brackets for hanging soffits, brickslips and so on, and the masonry supports themselves, there’s more complex design and installation challenges than you would experience with, say, your standard two-storey cavity wall house,” McShane says. “It was a challenge to account for all of these junctions, however by considering these elements from the early stages of delivery they were part of the design considerations from the outset with the contractor and supplier.” Embodied CO2 Fabric-first approaches like passive house may have largely done away with space heating loads, thereby drastically reducing operational energy use, but what about the energy used and carbon emitted in the construction of a building? As Ann-Marie Fallon explains, a study was carried out on a block from the current phase of Agar Grove using Eccolab, Architype’s new carbon cost and energy tool, comparing the tendered construction methodology – cross laminated timber – with the concrete frame and masonry-based approach used on phase one. The tendered design, if developed as a net zero carbon building with future 2050 de-carbonised electric emission factors applied to energy, has an almost 95% improvement on its total carbon emissions over a 60-year life. This

ph+ | agar grove case study | 29


AGAR GROVE

CASE STUDY

AGAR GROVE

Idealcombi Futura+

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Windows. Developed, Tested and Manufactured in Denmark. 30 | passivehouseplus.co.uk | issue 31


CASE STUDY

AGAR GROVE

Fuel poverty is a significant issue for many of the estate’s fixed income residents.

SELECTED PROJECT DETAILS

supports research elsewhere indicating that in 30 years’ time, the biggest carbon emissions in buildings will come from embodied rather than operational carbon emissions. “As designers we need to be assessing buildings in much more detail with this in mind for future life span adaptability,” says Fallon. Summer comfort PHPP determined an overheating risk of 6% for Block A (meaning the indoor temperature is expected to be above 25C for 6% of the year). All very well in average summer conditions, but 2018 and 2019 were two of the hottest summers on record in London. Fallon says that some changes to the glazing specification were implemented to mitigate the risk of overheating, such as a planning amendment to reduce glazing areas, and the careful application of g-value (solar gain value) changes, to east and west façades in particular. The large balcony that runs the length of the south façade is also critical to the shading strategy. A post occupancy survey carried out by Camden found that 75% of residents were either comfortable or mostly comfortable during the summer months of 2018. During the last three weeks of July 2019, when temperatures in central London averaged 24C and reached a high of 38C during an extreme heatwave, average internal temperatures across three monitored units —  each with blinds and windows in different modes of operation — was 26C. It is not believed that internal temperatures peaked any higher than 28C when external temperatures were 38C, but this is currently undergoing thorough review by Camden, and more detailed information will be available in future. The project team is currently assessing data from the previous 15 months, and Camden will continue monitoring for the next two years. An important part of the overheating criteria being met alongside the above measures was the agreement with the certifier WARM on a robust summer ventilation strategy (cross ventilation and purging heat by opening windows at night). This was included and

advised on in the home user guides circulated by Camden to all occupants. Subsequent phases of the scheme are now undergoing more detailed modelling of future performance and comfort under different future climate warming scenarios, as now required by the Greater London Authority. Fallon says in future it’s important that critical rooms in dwellings are modelled individually, in addition to the more general overheating analysis in PHPP — and stresses that sensible glazing ratios are always the best line of defence. Provisional findings by Architype on behalf of Hill, who carried out the first 12 months of monitoring, found an average winter temperature of 22C, average humidity of 40% and very low CO2 levels. Findings presented by Architype at the London Future Build conference this year and at the Heidelberg Better Buildings conference suggests a 71% reduction in heating bills is possible for phase one residents (compared to 2018 Annual Fuel Poverty Statistics, see ‘In detail’ for more). Camden are assessing the live metering data from the block currently to verify these findings for real. Meanwhile, the UK Passivhaus Trust also recently completed a successful day of talks on Block A as a kick-off event for London Climate Action week at the start of July, giving perspectives and feedback from all the design and delivery stakeholders in the project. Michelle Christensen says residents are very happy in their new homes. The fact that the council was dealing with an existing community from the very beginning meant that everyone had plenty of time to get used to the idea of passive house. “We did home demonstrations when people moved in, and a week later we did some more. After each season, we knocked on doors and handed out questionnaires and did quite a bit of trouble-shooting, making sure people knew how best to use their home.” “I’ve been in 95% of homes on the estate,” she says, “you get to know people, and they know who to call if they have issues. It took a while to earn that trust, but having it makes a huge difference to everyone.”

Main client: London Borough of Camden Client: Hill Partnerships Ltd (in D&B contract with main client) Design architects: Hawkins Brown Delivery architects: Architype Engineers: Stantec (formerly Peter Brett Associates) Quantity surveyors: Arcadis Passive house design: Architype Passive house site support: Enhabit Passive house assessment: WARM Airtightness testing: Enhabit/Paul Jennings Energy rating assessment: NRG Consultants M&E engineering: Mark Robinson Associates & Max Fordham Cavity insulation: Knauf Service cavity insulation: Isover Additional wall insulation: Kingspan Foundation system: Jablite Windows: Idealcombi Doors & curtain walling: Schueco Fire-rated internal doors: Premier SSL Roof windows: LAMILUX UK Airtightness products (tapes and membranes): Ecological Building Systems Airtightness products (parge coat): Tarmac Building Products Cavity wall ties: Ancon Thermal breaks: Halfen, Schoeck, Armatherm Brick slips: Eurobrick Masonry supports: ACS AAC blocks: Forterra Fixings (soffits and walkways): Nvelope PV Panels: Ample Energy Heat recovery ventilation systems: Zehnder / Swegon Heating system design: SAV Heating & ventilation system installation: Morgan Cass Heat recovery ventilation (design): Mark Robinson Associates Solar shading: Contrasol

Read more about this project in detail

ph+ | agar grove case study | 31


AGAR GROVE

CASE STUDY

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CASE STUDY

AGAR GROVE

IN DETAIL Building type (Block A): 38-unit, seven-storey residential block. Concrete frame & infill blockwork cavity wall construction.

large scale multi-unit high-density approach, and good site placement for orientation compensates for this.

Location: Agar Grove, Camden, London

Thermal breaks: Armatherm FRR thermal break pads, Halfen HIT insulated connections, Schoeck Isokorb connectors, TeploTie cavity wall ties, Thermalite blocks.

Completion date: April 2018 Budget: Not disclosed Passive house certification: Certified (Block A certified as one building) Space heating demand (PHPP): 13 kWh/m2/yr Heat load (PHPP): 9 W/m2 Primary energy demand (PHPP): 118 kWh/m2/yr Heat loss form factor (PHPP): 1.6 Overheating (PHPP): 6% Environmental assessment method: Code for Sustainable Homes L4 Airtightness (at 50 Pascals): 0.6 ACH on certificate, 0.59 ACH reported final test Energy performance certificate (EPC): B 83 kWh/m2/yr Thermal bridging: Concrete frame with infill 200 mm AAC blockwork cavity wall using Ancon TeploTies, thermally broken masonry support system and series of thermal breaks within junctions on concrete frame. Thermal bridges in their totality make up 66% of the heat loss of the scheme. The optimised form,

Energy bills (measured or estimated): Projected average annual gas bill of £162 per year per unit (£47 p/a for space heating, £115 for domestic hot water), including standing charges & VAT (for 4,000 kWh per year for space & water heating, as per PHPP). This is approximately a 71% reduction on average relative to the reference 50-69 sqm apartment in the 2018 Annual Fuel Poverty Statistics (£560 for 13,793 kWh/m2/yr). Ground floor: 150 mm compacted base followed above by 50 mm sand blinding, 250 mm concrete slab, RIW Gas Seal Blue DPM, 135 mm Jablite classic EPS, 75 mm screed, varies floor finishes. U-value: 0.25W/m2k. Walls: External leaf of, variously, brick or P-clad brick slip or followed inside by 150 mm cavity fully filled with Knauf Supafil insulation (includes height waiver for installation), 200 mm Thermalite Hi strength 7kN AAC block work with 10-15 mm parge coat to outer face as airtightness layer, internal stud lining (thickness varies). U-value: 0.165W/m2k. Roof: Bauder extensive biodiverse/brown seed roof with Flora 3 seed mix (mix of sedum and plug plants suitable for an urban

living roof as per planning requirements). Bauder PIR insulation under growing medium varying from 140 mm to 270 mm thickness for drainage and falls and sitting on vapour control membrane and 250 mm concrete slab. U Value: 0.09W/m2k. Windows & external doors: Idealcombi Futura + timber alu-clad range for domestic doors and windows, g-value modifications to windows to mitigate overheating risk where required. Reference overall U-value: 0.74 W/ m2k (European test size). Schueco communal entrance doors. Premier SSL fire doors for FD60 and FD90. Roof windows: LAMILUX F100 smoke lift glass skylights. Overall U-value: 1.0 W/m2k for reference size. Heating system: Communal heating system. 5 x Broag Remeha Quinta PRO gas boilers arranged in cascade feeding individual, insulated Danfoss Flatstation heat interface units (HIUs) in each apartment with fully insulated manifolds, pipework and connections. No hot water storage in dwellings, the HIUs provide a heat boost as demanded. Heating distribution per flat consists of 1 x radiator in the living room and 1 x towel radiator in the bathroom. Ventilation: 28 units ventilated by centralised MVHR system (2 Swegon Gold RX units). Individual maisonettes on the ground floor ventilated by individual Zehnder Comfoair Q350 units. Water: Restricted waterflow taps to satisfy Part G of the Building Regulations.

ph+ | agar grove case study | 33


EAST SUSSEX

CASE STUDY

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

34 34 | passivehouseplus.co.uk | issue 31


CASE STUDY

EAST SUSSEX

STRO NG & STAB LE E AST S U S S E X H O M E WI T H A ST RIKIN G FA R M YA R D - I N S PI R E D D E S I G N

While this striking new larch-clad home in rural East Sussex ultimately received the backing of the local planners, there was just one catch: it had to meet the passive house standard before its owners could move in.

Words by David W Smith

A

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£11.50 per month for space heating (estimate, see ‘In detail’ for more)

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Hit & Miss Vertical Poplar Platowood Platonium 05 Timber Cladding

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Vertical Standing Seam Zinc Cladding

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Vertical Poplar Platowood Platonium 05 Plank Timber Roof

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Single Ply Membrane Flat Roof to Canopy

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Galvanized Steel PFC Profile

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Triple Glazed Composite Timber/PPC aluminium windows, RAL 9007

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PPC Aluminium Door to Main Entrance, RAL 9007

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PPC Aluminium Insulated Infill Panel, colour to match windows frame

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1:50 0 File Ref:

PLEASE NOTE FOR CONSTRUCTION PURPOSES USE ONLY FIGURED DIMENSIONS. THIS DRAWING MUST ALWAYS BE READ IN CONJUNCTION WITH ALL RELEVANT PROJECT DETAILS. ALL DIMENSIONS MUST BE CHECKED ON SITE PRIOR TO COMMENCEMENT. PLEASE REPORT ANY DISCREPANCY TO THE ARCHITECT OR CONTRACT ADMINISTRATOR © COPYRIGHT HMY 2014

Revisions P 1 01.09.17 P 2 25.10.17 P 3 16.11.17 P 4 30.11.17 P 5 01.12.17 P 6 19.02.18

RRM RRM RRM RRM RRM RRM

Preliminary Issue Issued for Information Revised door sizes and opening type. Design Changes Added Twin Wall Flue. Amended Windows Sightlines. Ammended window WF-01 position to accomodate lintel above.

1

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1927_ 107_ P6

Drawing

Date

Proposed Elevations

Sep 2017

Project/ Client

Norlington Gate Farm Mr & Mrs A Cloke Job Reference

Drawing Number

1927_ 107

Scale @ A1

1 : 50

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P6

Purpose of Issue

Construction

Hazle McCormack Young LLP/ Chartered Architects/ Leap House/ Frog Lane/ Tunbridge Wells/ Kent/ TN1 1YT/ T 01892 515311/ F 01892 515285

Building: 153 sqm structural insulated panel (SIPs) house Completed: September 2018 Location: Ringmer, East Sussex Budget: £400,000 Standard: Certified passive house

ph+ | east sussex case study | 35


EAST SUSSEX

CASE STUDY

O

pposition to their planning application led to delays and redesigns, but homeowners Adrian and Paula say their struggles were worth it once they moved into their new passive house in the village of Ringmer, in Sussex. “The experience of living in the house is, frankly, amazing. I never thought it would perform as it does, as nothing ever seems to live up to expectations. The passive house consultant — Marine Sanchez, from Enhabit — said we wouldn’t realise how comfortable it was until we moved in and it’s absolutely true,” says homeowner Adrian. A major benefit of living in a passive house for Paula is the constant temperature. She has Raynaud syndrome, which causes poor circulation, and can find sudden drops in temperature painful. The poor insulation and drafts in the couple’s old house, a converted long barn on the same plot of land, was hardly ideal. “Our passive house maintains a temperature of 21 degrees during the winter,” says Adrian. “Even if the temperature outside is freezing and it drops overnight to 18 or 19C [inside], as soon as you get up and switch the kettle on, and other such day to day tasks that generate heat, it soon moves up to 21C. We put in a wood burner in the kitchen, but we barely need it. We only used the central heating for about 10 hours all last winter.” He also says there has been no issue with overheating to date. “The house generally stays at quite a pleasant ambient temperature when it is hot outside.” The couple first approached architect James Galpin, of Hazle McCormack Young in January 2017. Their original intention was to convert an old equestrian barn on their

36 | passivehouseplus.co.uk | issue 31

disused dairy farm into a more ecological house than the one they were living in. That building had Class Q planning permission attached (which allows conversion of agricultural buildings to dwellings), and Adrian’s research had discovered identical barns that been converted to homes before. But when the couple realised how much of the 153 square metre space would have to be lost to insulate it internally, they opted instead to replace the barn with a new house, using structural insulated panels (SIPs) within the same footprint. There were strong objections to the new design from Ringmer Parish Council, but the planning committee at Lewes District Council took a different view. It ultimately gave its approval, but this was conditional on achieving passive house certification, as the council wanted the development to be a beacon of ecological design in the local area. “It had to be certified by the Passive House Institute to be legally inhabitable, so that was a bit worrying, and we were all relieved when the final air tests were complete, exceeding the required levels significantly,” he says. Work began on constructing the three-bed £400,000 development in February 2018, and was complete in September that year. The contractor, Nigel Jeffery of Rexstone Builders, had never worked on passive houses before, but by all accounts, mastered the art quickly. According to Jeffery, while passive house is a significant advance on current practices in the industry, it also harks back to earlier times: “I think it’s reverting back to old building techniques. A lot more care is needed,” he says. At the start of the process, Jeffery and his colleagues listened to the arguments being

Explained Structural insulated panels (SIPs) are prefabricated, structural building panels comprising insulation – typically polyurethane – sandwiched between two layers of OSB.

I think it’s reverting back to old building techniques. A lot more care is needed.


CASE STUDY

EAST SUSSEX

Photography: Andy Stagg / Dug Wilders

It had to be certified by the Passive House Institute to be legally inhabitable.

ph+ | east sussex case study | 37


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VENTILATION SOLUTIONS TO SUIT ALL LOW ENERGY HOMES Nilan UK Tel: 01403 563045 - 07919 444452 Email: info@nilanuk.com 38 | passivehouseplus.co.uk | issue 31


CASE STUDY

EAST SUSSEX

CONSTRUCTION IN PROGRESS SELECTED PROJECT DETAILS

1

2

3

4

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6

1 300 mm Isoquick insulated raft foundation; 2 the house was constructed using structural insulated panels comprising 175 mm polyurethane insulation sandwiched between two layers of OSB; 3 the pro clima Solitex Fronta WA membrane provides optimum protection for the roof structure; 4 aside from the insulation in the structural insulated panels, the wall build-up also features 100 mm Kingspan TW55 insulation boards; 5 insulated MVHR ductwork for both the supply air side and the extract air side; 6 pro clima DB+ vapour control membrane fitted to walls and roof, with airtightness taping at membrane overlaps and around window junctions.

Architect: Hazle McCormack Young (HMY) Contractor: Rexstone Builders Passive house consultant: Enhabit M&E design: HMY / Enhabit SIP building system: SIPCO External insulation: Kingspan Insulated raft system: Isoquick Windows & doors: Norrsken Airtightness products: Pro clima Heat recovery ventilation: Zehnder Cladding: Alsford Screeds: WoollyCrete Wood burning stove: Morso Lighting: Phillips Hue Heating controls: Nest

made about passive house with a pinch of salt. “To be honest, when we were at meetings about this project the passive house designer gave us all this information about passive house that we were a little bit skeptical about, but went along with,” he says. “But everything they said has come true.” The toughest technical challenge on the build was to create a firm sub-structure, as the clay was highly shrinkable. “It was a bit of a head scratcher for a while, but we ended up pouring a slab of sacrificial concrete over the shrinkable clay that acted as a non-shrinkable ground layer, then we built the rest of the structure up from that,” says architect James Galpin. The detailing of the larch cladding on the roof posed further technical challenges. Galpin says it was important to get the detailing of the verge cladding and rainwater drainage integrated into one detail so there were no visible downpipes or drainage elements within the building. “It’s all detailed as part of the skin to keep one homogeneous volume without any attachments,” he says. In designing the house, Galpin aimed for a visual connection between the interiors and the picturesque surrounding landscapes. There are splendid views across the Sussex downs, near the town of Lewes and the village of Firle. “The key was to balance the views from the glazing layout with solar gain and the shading required for the avoidance of over-heating,” he says. The big Norrsken windows at the front and back of the house are all floor-to-ceiling, flooding the rooms with light. “Almost every window in the house presents amazing views. We love it because it’s like having pictures hanging on the walls everywhere,” says Adrian. “In rooms with double and triple aspects, we are surrounded by countryside.”

Read more about this project in detail

ph+ | east sussex case study | 39


EAST SUSSEX

CASE STUDY

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40 | passivehouseplus.co.uk | issue 31

High Performance Windows & Doors


CASE STUDY

EAST SUSSEX

IN DETAIL Building type: 153 sqm detached two-storey SIPs-built house
 Location: Ringmer, East Sussex Completion date: September 2018 Budget: £400k Passive house certification: Certified Space heating demand (PHPP): 14 kWh/m2/yr Heat load (PHPP): 10 W/m2 Primary energy demand (PHPP): 104 kWh/m2/yr Heat loss form factor (PHPP): 2.98 Overheating (PHPP): 9% No. of occupants: 3 (plus two dogs & a cat) Airtightness (at 50 Pascals): 0.42 air changes per hour or 00.28 m³/m2/hr Energy performance certificate (EPC): N/A Thermal bridging: SIPs supported at low

level on Compacfoam CF 400 to bring base level of SIPs to 150 mm above external ground without forming a cold bridge at the base of the structure. Support to external entrance canopy designed to cantilever with only minimal restraint ties to the main structure, preventing cold bridges. Energy bills: Estimate of £138 per year (£11.50 per month) for space heating only, based on bulk LPG price of 5.8C per kWh (confusedaboutenergy.co.uk, July 2019), PHPP space heating demand projections & boiler efficiency of 90.1%. Ground floor: 250 mm polished concrete reinforced slab, on 300 mm Isoquick insulated raft, on 200 mm in situ concrete, on Cellcore former to alleviate shrinkable clay ground conditions. U-value: 0.107 W/m2K Walls: Hit-and-miss larch cladding on battens, on Pro clima Solitex Fronta breather membrane with Tescon Invis tape at joints, on 100 mm Kingspan TW55 insulation, on 200 mm Sipco SIPs comprising 175 mm polyurethane insulation sandwiched between two layers of OSB, with Pro clima DB+ vapour control membrane and battened plasterboard internally. U-value: 0.096 W/m2K

Roof: Hit-and-miss larch cladding with spacer fixings on battens fixed through trapezoidal drainage layer, on battens and counterbattens, on Pro clima Solitex Plus breather membrane, on 120 mm Kingspan TP10 insulation, on 200 mm Sipco SIPs (as per wall spec) with Pro clima DB+ vapour control membrane and battened plasterboard internally. U-value: 0.090 W/m2K Windows & external doors: Norrsken P33A inward-opening alu-clad triple glazed timber windows. Low E glass, argon fill. Sealed with Pro clima tapes. Typical whole window U-value: 0.74 W/m2K Heating system: Viessmann Vitodens 200-W 19kW LPG-fed boiler system with client sourced radiators. Ventilation: Zehnder Q350 MVHR system with passive house certified heat recovery efficiency of 90%. Water: Restricted waterflow showerheads and tap outlets. Shading: Delivered by inset of windows and the modelling of the verge detailing to minimise solar gain in summer.

ph+ | east sussex case study | 41


STEEP WEDGE

CASE STUDY

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

42 42 | passivehouseplus.co.uk | issue 31


CASE STUDY

STEEP WEDGE

S T E E P LY S U S TA I N A B L E L O W C A R B O N PA S S I V E D E S I G N T R I U M P H ON IMPOSSIBLE CORK SITE The unique split-level, wedge-shaped plan of this striking and award-winning new passive house in Cork isn’t just for show — it is a carefully thought-out response to an extremely challenging site, and an example of how great architecture can create beautiful, sustainable buildings in even the most unlikely of spaces, and with a fraction of the upfront carbon costs of traditional build methods.

Words by John Cradden

€95

per year (calculated space heating use)

Building: 180 sqm split-level timber frame house Completed: September 2017 Location: Douglas, Co Cork Budget: €360,000 Standard: Passive house certified Embodied carbon: Circa 35% of the CO2 emissions of a comparable traditional build*

* See box out on upfront carbon costs for a detailed explanation and breakdown of the embodied carbon calculations.

ph+ | steep wedge case study | 43 43


STEEP WEDGE

CASE STUDY

T

his house looks at first like one of those highly ambitious contemporary ‘grand designs’ built as a no-expensespared showcase for the talents and imagination of the team of architects, engineers and builders behind it. Although it has clearly been designed to fit on a steeply sloping site, this wedge-shaped home would surely win awards for its aesthetics alone. The true story of its gestation is as far from this first impression as you could imagine. This 180 square metre passive-certified home, built on a very tight budget, has certainly won awards, but they are as much for its highly sustainable and resourceful response to a very technical and problematic brief as for its striking appearance. Indeed, in choosing this compact house design as its overall winner, the judging panel of the 2019 Isover Awards described it as “the perfect way of doing things in terms of sustainability and design”. “The design responds ingeniously to an extremely challenging suburban site to prove that world-class energy performance can be achieved with show-stopping aesthetics, utilising low embodied energy materials,” the judging panel said. Located in the Cork city suburb of Douglas, the house was designed and built by architect Gareth Sullivan as his family home. “As a young family looking for our first home,

44 | passivehouseplus.co.uk | issue 31

we became disillusioned with rising house prices and poor availability of quality choice in the market,” he says. They wanted to be close to the city so even the possibility of a self-build looked to be unattainable given the high price of good sites in the area. So, they decided to look for a more challenging one. “We set eyes upon a steeply sloping site which had an abundance of issues and apparent problems. It looked implausible, but it was affordable,” says Sullivan. The fact that the site was being sold without planning permission was a further risk, but “having researched the various restrictions presented by the site, we had just enough confidence they could be overcome, so we took the plunge and bought it”. While Sullivan makes it sound like a reasonable risk, it’s easy to see why the site was viewed by its previous owners as nothing more useful than a builder’s yard. Besides its steeply sloping nature, the site has no less than three wayleaves — protected access routes to various county council services pipes — across it. A minimum separation distance needed to be observed for each. “The services don’t run through our site but essentially we couldn’t build too close to them,” Sullivan says. What this meant was that only a small wedge-shaped plot in the corner of the site could be developed, and even access to


CASE STUDY

this was awkward. Furthermore, the county council placed restrictions on the ridge height and south-facing windows to prevent the property overlooking a neighbouring site, severely limiting the house’s solar gain. So, the house design, as it evolved, was shaped primarily by the need to overcome each of these obstacles. This certainly explains the compact wedge-shaped form, but the solar gain challenge was addressed partly by a PHPP (Passive House Planning Package) analysis to ensure the building fabric would be of a higher standard to compensate, while windows on the south-facing side were set high enough to avoiding any overlooking issues. Additional roof lights also helped, and the living spaces are separated over three levels to track the sun’s path. Sullivan and his wife, Barbara, bought the site in 2013 and began a lengthy process of liaising with Cork County Council service engineers and the local planner, John Lalor, who was thankfully open-minded. “It took a few design iterations to finally reach a point where planning was secured, and all issues were carefully managed to ensure our house would not negatively impact access to the services or be overbearing for any of our neighbours.” They continued to take their time with the second phase, that of detailing the design and mobilising the construction, which included deciding to self-build. “The self-build approach wasn’t always a given but in the end it was a budget-driven decision to try and reach the level of quality we wanted to.” “We did consider using a main contractor but once we decided to use a timber frame system it gave me the confidence to take on

Photography: Jed Niezgoda & Gareth Sullivan

the self-build challenge, as the ECO Timber Frame package also included insulation and airtightness.” Starting the build in August 2016, it took a big co-ordination effort by Sullivan to keep things on track to finish just over a year later. He did a useful bit of the labouring work in his spare time and various family members chipped in, too. “It was actually really nice to share the experience of building the house.” Needless to say, there was much design and engineering head-scratching with the build, according to Sullivan, ranging from maximising light to ensuring the flow of the house wasn’t compromised by separating the different levels, and the difficult orientation. One fairly significant detail was the frameless glass wrapping around the corner from the entrance door, which required structural steel so that the engineer could cantilever that corner to eliminate the post. But the reward was an extra 300 mm in width to the very narrow entrance, which was badly needed to give it a greater sense of space on arrival. “Little challenges like this were overcome by some subtle but well-considered moves that thankfully have worked to make the house feel more spacious despite the restrictions,” says Sullivan. As well as meeting the passive house standard, Sullivan was keen to opt for as many natural materials as possible for the building fabric, something that clearly got a nod of approval from the Isover Award judges. The ECO Timber Frame package and decision to opt for Aquapanel cement board instead of a blockwork outer leaf is

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We set eyes upon a steeply sloping site… It looked implausible, but it was affordable.

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The best thing about this project is that it has given us a home.

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probably the most significant element, along with Steico woodfibre board and cellulose recycled newspaper insulation. Even the slate adorning the entrance roof has strong green credentials: Penrhyn Bangor Blue slates boast a projected lifespan measured in centuries, require very little embodied energy to process, and come from the only slate manufacturer in the world that operates to ISO 14001. In this case Celtic grade slates were used – a heavier grade of Welsh slate designed to withstand the harsh climates in Wales, Scotland and Ireland. But what does this thoroughly green-sounding building spec mean in terms of measurable environmental impact? Passive House Plus called in the services of Tim Martel, publisher of PHribbon, an add-on to PHPP, the software that’s used to design passive houses, to attempt to work out the effect of these material choices. The results are explained in detail in the box out here, and they’re significant: the house apparently has less than a quarter of the upfront carbon costs it would have had if built to the same standard using a typical cavity wall build method.

Architect Patrick Bradley, one of the Isover Awards judges and a well-known face from RTÉ’s Home of the Year programme, said what makes Steep Wedge House so special is the way it manages to merge both sustainability and aesthetics on a very tricky site. “The architects created something out of a difficult site that’s very beautiful,” he says. “I thought the detail, and the understanding, and the problem solving that went into the project was excellent. It may just be one individual house, but it provides an example of how to combine sustainability and aesthetics for others to follow — it’s a beautifully designed project that meets the highest standards of sustainability, and that to me is what makes good architecture. The two go hand in hand.” Like with many self-builds, things are still evolving for the Sullivan’s even after two years, but so far, the house has proved very flexible for the couple and their two toddlers, and Gareth Sullivan says it remains “consistently comfortable”. He adds: “We have a guest bedroom near the living spaces which has been used mainly

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as a playroom and then it converts back when guests come to stay. This was an important feature of the house for us as we wanted to make sure we wouldn’t have spaces that would be wasted, and this is working really well.” The couple are also enjoying one of the key features of the house, which is the connection to the garden at the lowest level directly off the kitchen. “As this part of the site is covered by mature trees, we have an unusual sense of escape and it is easy to forget we are in a built-up suburban area. This and the sense of light we get in different parts of the house throughout the day are the highlights for us.” There is also the benefit of being able to reside close to Douglas village, where Barbara grew up, and which is an easy cycle commute to the city. “At the end of the day, in spite of all the design challenges, the problematic site and the technical rigour to achieve the passive house standard, the best thing about this project is that it has given us a home. In so many ways that is the most satisfying thing.”

CONSTRUCTION IN PROGRESS

1

2

3

4

5

6

7

8

9

1 The ground floor features a raft foundation consisting of a 300 mm insulation system by Kore, with underfloor heating also installed at this stage; 2 followed by the concrete slab with service penetrations; 3 a close-up of wall insulation details at the retaining wall; 4 erection of the factory-built Eco Timber Frame system; 5 Steico 22 mm woodfibre board wrapping the timber stud; 6 the timber frame nearing completion, with Aquapanel cement board externally; 7 measuring the depth of the Ecocel cellulose-filled timber stud; 8 Rockwool insulation installed in 50 mm service cavity; 9 insulation, airtightness taping and membrane at triple glazed roof window.

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CALCULATIONS SUGGEST UP TO 77% REDUCTION IN EMBODIED CO 2 By Tim Martel, AECB

T

he embodied CO2 of Steep Wedge House was calculated with PHribbon, an add-on for PHPP published by the AECB. We wanted to compare the house as built using timber frame and a slate roof with cavity wall of the same U-value and a concrete tile roof. PHribbon works within PHPP and helped speed up the process. Calculations were from a new version currently being tested that includes transport and there were some adjustments that were made by hand to the final spreadsheet. The software creates a table on a new Excel tab in PHPP and writes figures as formulas. Internal walls, intermediate floors and the slate roof aren’t included in the PHPP but the software now enables these to be selected and entered. Alternative rows for a cavity wall construction, strip foundations and concrete tiles were also added. The entire house comes in at an estimated total embodied CO2 reduction of 41 to 80% compared to the reference house, depending on whether carbon sequestration in timber products is excluded or included. The biggest savings were from I-beam walls with cellulose insulation instead of concrete blockwork, which also halved transport CO2. Overall, and without counting sequestration, the walls - including Aquapanel cement boards instread of blockwork rainscreens - came in at 8-10 (average: 8.9) tonnes of CO2,

compared to cavity walls at 33-37 (average: 35) tonnes CO2. The analysis excluded the concrete retaining wall. Some uncertainty is reflected in error bars of the result. Most of this is from transport. Some is from variations in installed density (further variability, the variation of embodied CO2 results is being added to PHribbon). Generally, EPDs were favoured if available and a couple were added to the PHribbon library, for KORE EPS insulation and Knauf Aquapanel cement board. An accuracy label is included in the spreadsheet. EPDs were considered good accuracy and the ICE database medium accuracy because the product used may not necessarily be that close to the average across many manufacturers – though it’s important to note that it corresponds to UK averages, which may differ from Irish figures. There were a few low accuracy results where neither of those were available and reasonable assumptions had to be made. There are differing opinions on whether sequestered carbon from timber should be taken into account and the AECB suggested that any storage from timber was not included. Another article is due to come out soon on this. Transport is included. Generally distances were not known so upper and lower figures were derived from three realistic local and long distance scenarios. Local delivery

lorries are often loaded at poor capacity – in this case 30% was used (by weight or volume, whichever is the greater). Return distances from the factory ranged from 120 to 900 mile round trips using two lorry sizes at 30 or 70% capacity. For long trips a smaller capacity local delivery lorry was added. For some materials distances were known from manufacturer to site, but delivery distances were still multiplied by 1.2 to 1.5 to account for extended routes of multi-drop deliveries via a distributor. Windows from Latvia were calculated with a large container ship, small container ship and by road.

SELECTED PROJECT DETAILS Clients: Gareth & Barbara Sullivan Architect: Simply Architecture Passive house certifier: Earth Cycle Technologies Civil & structural engineering: Tanner Structural Designs Energy consultant: Evan Finnegan Timber frame: ECO Timber Frame Quantity surveyor: KSQS M&E contractor: Energywise Ireland Heat pump: Daikin, via Energywise Ireland Heat recovery ventilation: Brink, via Energywise Ireland Airtightness tester: Pro Air Tight Testing External render: MS Plastering Cladding: Aquapanel, via Greenspan Windows & doors: Viking, via West Windows & Doors Roof windows: Sky Frame, via West Windows & Doors Cellulose insulation: Ecocel Floor insulation: KORE Screed contractor: Premier Floor Screed Screed: Cemfloor, via McGrath’s of Cong Oak flooring: Del Forno Tiles & Timber Roof: Singly Ply Roofing Roof slates: Lagan Building Solutions

Read more about this project in detail

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Welsh Slate’s Dark Blue Grey Cwt-y-Bugail roofing slate on the Coal Drops Yard, Kings Cross, London

INNER STRENGTH

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IN DETAIL Building type: 180 sqm detached (2.5 storey) split level, timber-frame dwelling on sloping site. Location: Douglas, Cork Completion date: September 2017 Budget: €360,000 (not including site cost) Passive house certification: Certified Space heating demand: 22 kWh/m2/yr Heat load: 10 W/m2 Primary energy demand: 60 kWh/m2/yr Heat loss form factor (PHPP): 3.29 Overheating: 6% of year above 25C Number of occupants: 4 Energy performance coefficient (EPC): 0.282 Carbon performance coefficient (CPC): 0.255 BER: A2 (43.9 kWh/m2/yr) Environmental assessment method: N/A Measured energy consumption: Pending Airtightness: 0.56 ACH at 50 Pa Thermal bridging: Timber frame system on EPS insulated raft ensured thermal bridge free junctions. Wood fibre insulation to exterior face and reveals. Y-value (based on ACDs and numerical simulations): 0.01 W/mK

screed around underfloor heating pipes; On polythene membrane; on 40 mm Steico Therm woodfibre insulation board; on OSB decking, on 375 mm deep open web floor joists with 100 mm Rockwool sound insulation. Rendered walls: Factory-built timber frame with Weberend MT render system externally on 15 mm Aquapanel cement board, on 75 x 50 mm vertical battens, on Proctor Frameshield breather membrane, on Steico 22 mm woodfibre board, on 295 x 38 mm cellulose-filled timber stud, on 15 mm taped and sealed OSB, on 50 mm service cavity insulated with Rockwool insulation, on 12.5 mm plasterboard. Where externally render is replaced by timber cladding; 18 mm Iroko vertical cladding, on battens and counter battens on Tyvek UV facade membrane. U-value: 0.11 W/m2K Retaining wall: Geo-textile membrane externally on drainage membrane, on 200 mm Kingspan Styrozone N 300R insulation, on Preprufe 300R membrane, on 200 mm concrete retaining wall to structural engineer’s design and specifications, on 25 mm top hat steel battens with 25 mm Isover Metac insulation between, 12.5 mm plasterboard slab internally. U-value: 0.13 W/m2K High pitch roof: Blue Bangor Penrhyn Celtic Grade rugged natural slate externally on 50x35 battens/counter battens, followed underneath by Icopal Monarperm 700 breather membrane, 350 mm rafters fully filled with cellulose insulation, PROFiSOL airtight membrane, 50 mm uninsulated service cavity, 12.5 mm

plasterboard ceiling. U-value: 0.13 W/m2K Low pitch roof: Sarnafil PVC membrane on S-Felt externally, on 25 mm Marine plywood, on 50x35 battens/counter battens, on Icopal Monarperm 700 breather membrane, on 346 mm timber I-joists fully filled with cellulose insulation, on PROFiSOL airtight membrane, on 50 mm uninsulated service cavity, on 12.5 mm plasterboard ceiling. U-value: 0.11 W/m2K Windows: Viking S14 & S11 triple glazed timber-alu clad windows with argon fill. Average overall U-value: 0.8 W/m2K Roof windows: 3 x Sky Frame flush triple glazed roof lights. Overall U-value: 0.9 W/m2K Heating system: 8kW Daikin Altherma 2 split system air-to-water heat pump with SPF of 356% supplying underfloor heating (& radiators to mezzanine). 260 litre integrated indoor unit. Stove: Contura i5 5Kw wood burning stove. Ventilation: Brink Renovent Excellent 400 Plus MVHR system. 84% efficiency certified by Passive House Institute. Water: Low flow fixtures. Electricity: Wired for PV panels to roof to allow ease of future installation Green materials: Timber frame, cellulose insulation, woodfibre insulation, cement boards.

Energy costs: Estimated space heating costs of €95.57/year based on DEAP heat pump tool calculated value of 503 kWh/yr, assuming €0.19c per unit. Stove with free wood supply estimated to use 369 kWh/yr. Ground floor: Concrete raft on 300 mm EPS insulated system by KORE. U-value: 0.10 W/m2K First floor: BOEN engineered oak wood flooring; on underlay; on 50 mm Cemfloor

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DEVELOPING STORY LIFE INSIDE IN IRELA N D’ S LA R GE ST LOW E N E R GY H OU SI N G SC H E M E

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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

€620

per year (space heating & hot water — see ‘In detail’ for more) Buildings: 1,950-home sustainable neighbourhood Completed: Work still in progress Location: Dún Laoghaire, Co Dublin Standard: A2 & A3 (BERs)

Over the last decade, Cosgrave Developments have set about building a new neighbourhood near the south Dublin seaside town of Dún Laoghaire. Honey Park and Cualanor are two adjacent schemes comprising nearly 2,000 low energy homes, one of which houses this magazine’s editor, who has found a scheme with green credentials that go far beyond a good energy rating.

Words by Jeff Colley

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above The two developments of Honey Park (top) and Cualanor (bottom) have a combined total of over 1,950 new homes, the vast majority of which have A2 BERs, as well as a 2,500 sqm shopping centre.

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I

n all the years I’ve been writing about low energy buildings, I’ve never had the chance to live in one. The stories we heard over the years from occupants of these buildings – about a palpable difference in comfort and anecdotal evidence of health improvements – in some way were abstract or theoretical to me when my lived reality was renting buildings that were either too cold or too stuffy, and invariably with a bit of mould thrown in too, exacerbated by the lack of outdoor drying options. As serial renters, my wife Lauren and I had had a run of bad luck. We had lived quite happily and run the magazine for several years from a poorly built Celtic Tiger townhouse in Blackrock – complete with a 1 sqm backyard where you literally couldn’t stand a bicycle up on two wheels. Our first child, Rex, was born in 2013, and the house no longer met our growing needs. So we moved to a 1950s semi-d on Wainsfort Road, Terenure, where our daughter Sadie was born. This house was too remote from shops, given that neither Lauren nor I drive, and we had to move after a year when an electrician discovered the house’s electrics hadn’t been grounded and needed total rewiring. We hastily found a beautifully extended and renovated ex-corporation house on Kill Avenue, Dún Laoghaire that had been promised to us for three years. As lovely as this house – which had been upgraded to a B2 building energy rating (BER), but whose glassy extension made it prone to overheating – was, the transition upset Rex, who has since been diagnosed with autism. When the landlord changed plans and decided to sell up within our first year there, my wife and I were forced to look at our options. Working from home was

becoming challenging – Rex and Sadie were prone to bursting into the office to play – so we decided to look for something smaller, and keep a separate office. Lauren thought that we should look to stay in the area, to minimise disruption for Rex. As luck would have it, we found a new rental option in a development a vigorous stone’s throw away from our last house: Cosgrave Developments’ Honey Park. It was close and familiar – Rex had even been to the playground and lake in Honey Park, and we regularly used the small shopping centre built by Cosgrave on the edge of the scheme. The energy performance struck a chord too – an A2 BER, high levels of insulation and decent airtightness, with heat recovery ventilation. So in May 2017 we moved into the Neptune building, a brand new 198 apartment building in Honey Park, secure in the knowledge that as this was a build-torent scheme, we’d have about as secure a tenure as is possible in the Irish private rental market. The company took out a little office on Patrick Street in Dún Laoghaire. Honey Park sits on the site of what was once part of Dún Laoghaire Golf Club. Cosgraves bought that land in 2002, and developed plans to create two new developments: Honey Park and Cualanor, separated only by a road, which would ultimately consist of a combined total of over 1,950 new homes and a 2,500 sqm shopping centre. While building a new golf club for Dún Laoghaire Golf Course in Enniskerry and a bowls club on the periphery of the Cualanor land, Cosgraves started the proverbial groundwork at Honey Park by building the park that would provide the scheme’s focal point, including a lake, a sizable playground, green areas, wildflower meadows and a basketball court.

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I have to remember to check the weather on my phone in the morning.

I met developer Mick Cosgrave and consulting engineer Richard McElligott – in the local Costa coffee shop Cosgrave’s built, of course – to discuss the scheme’s quietly sustainable approach. Since starting out in 1979, Cosgrave Group have built 7,620 homes, in the process picking up countless awards and earning a reputation for quality. Over the intervening 40 years, the company has developed what it refers to as the five pillars of excellence, which the company lists as quality (design, specification and construction); sustainability (energy efficient living); low maintenance (reliable, long term solutions); user focused design (homes for people to enjoy); and community benefit (a stage for living). These five pillars are made manifest in Honey Park and Cualanor, and a long-term view that was evident in the genesis of the schemes. “The first thing we did was put in the park – five acres in that – before a house was built,” says Mick Cosgrave. “It’s a huge forward investment but it makes the place. You have

top and bottom left Both developments feature large parks and playgrounds, which help to create “a place that people want to live in”. Aside from retaining trees from the site where possible, mature plants are also added to help create a sense of place; right the impressive Honey Park playground provides a safe place for children to play and meet other kids from the area.

Photography: Image Works

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to create a place that people want to live in.” According to Cosgrave, aside from retaining trees from the site where possible, the group tends to put in mature plants to help create a sense of place. “So you arrive, it’s as if the house could have been there for five years. We’ve been doing that for the last 30 years.” “It’s more of a neighbourhood,” adds Richard McElligott. Cosgrave explains that the lake went in for more practical reasons – storm water attenuation – but grew into an opportunity to provide amenity for residents while also supporting biodiversity. “We decided to make something more of it, working with [environmental NGO] the Curlew Trust. They gave us all [the advice] to create the habitats to attract the birds.” Sure enough, the lake is home to a cacophony of ducks, moorhens, the odd heron, and of course, the inevitable pigeons. As someone who lives in Honey Park, I value having all of this nature on my doorstep, in a park with an impressive playground that people come from neighbouring towns to visit. Our two-bed apartment is 89.5 sqm, plus a balcony overlooking an internal courtyard. It’s sufficient for our needs, space-wise, but if cabin fever sets in we can take the kids outside in an instant to a place where they can burn off energy and have unstructured play with other kids. In our building there’s also a free gym and office pods – complete with Wi-Fi and coffee machine – where I regularly work, especially during magazine deadlines. Walkable communities Our office in Dún Laoghaire is a 15-minute

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walk away – a pleasant stroll through Honey Park’s sister scheme, Cualanor, taking in a forest trail with resident squirrels, and a walk past the playground in Cualanor’s own park. By happenstance or design, it’s more convenient for Cualanor residents to get to Dún Laoghaire on foot or bicycle than by car, thanks to pedestrian access at the rear of Cualanor, though the vast majority of residents still own cars, of course. Electric vehicles (EVs) are becoming a common sight in the two schemes, with several charge points installed in the underground car parks of the apartment buildings and high-speed chargers next to a GoCar car sharing club hub at the shopping centre. But a greener option than EVs is not to drive at all. My family are testament to the fact that it can be possible, easy, and – barring particularly inclement days – pleasant to get around by foot, whether it be for the daily grind of school and pre-school runs, shopping, work or weekend trips to the seaside, with frequent buses on our doorstep and trains only a brisk walk away. It was this overall attention to sustainability that made such an impression on the judging panel, which I sat on, for this year’s Isover Awards, where two new phases at Cualanor – Fairway Drive & Abbot Drive – picked up the Excellence in Residential New Build award and Runner Up & Contractor of the Year award. My fellow judge Pat Barry, CEO of the Irish Green Building Council, is effusive with praise: “This scheme exemplifies what creating sustainable communities is all about. We can’t tackle climate change with disconnected solutions. It won’t work if we build

above Spectacular views from a roof terrace at the Leona building; office pods at the Neptune building where part of this article was written; and the sky gym in the Leona building.


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A-rated homes that still lock in high carbon lifestyles. We know we have succeeded in creating a great community when the low carbon choices are the obvious ones, when the most sensible and pleasant way of getting to the local shop, school or work is by walking and cycling, through a beautifully-designed biodiverse landscape. We know success when it makes more sense to be part of the local car club, saving the costs of car ownership for something more worthwhile like leisurely lunches in a local community restaurant or browsing the farmers market. The carbon transition will be less about technical solutions such as heat pumps and electric cars and more about the soft design skills that enable behaviour change.” Energy use But what about energy use? The vast majority of the 1,950 homes between Honey Park and Cualanor come in at A2 BERs, and our apartment is no different: an A2 rating with a primary energy score of 43 kWh/ m2/yr covering space heating, hot water, ventilation and lighting – a net total which would be reduced by a contribution to the ‘landlord’ areas (communal spaces like lobbies, hallways and stairs) by a centralised combined heat and power plant. Since we moved in, we’ve used an average of 36.96 kWh/m2/yr at our heat meter, virtually entirely for hot water. In the 25 months that we’ve lived here, we’ve had perhaps one or at most two radiators on for about a week in total – and even then, sparingly. True, it’s a mid-floor, mid-block apartment, which gives it every advantage. But we live in a place that feels a lot like a passive house. It’s always warm – between 20 and 25C virtually all the time, though if memory serves it may have come close to 26C briefly last summer. I have to remember to check the weather on my phone in the morning – otherwise I have no idea whether my kids are wrapped up too warm or not for the school walk until we’re out the door. It’s a disarming experience, and living in a building like this takes a bit of getting used to, so ingrained are your behaviours from living in uncomfortable buildings. It takes a while to remember you never need to put on jumpers or socks indoors. The heat recovery ventilation also appears to be having a tangible, positive impact. My son has asthma, and his symptoms – which had been persistent up to that point – seemed to improve as soon as we moved

You have to create a place that people want to live in.

in. Flare-ups tend to coincide with trips away – to his grandparent’s naturally ventilated Celtic Tiger bungalow, or an English Center Parcs holiday home in July where the air was thick with the residue of charcoal barbeques. But when we get back home, the coughing quickly subsides. Mick Cosgrave is a strong advocate of heat recovery ventilation, the importance of which was impressed upon him following a trip in 2005 to the Passive House Institute in Darmstadt. “The heat recovery was the big thing for all this to work,” he said. “There’s no point in you insulating your house and having a hole in the wall.” Following that trip, Cosgrave installed heat recovery ventilation systems in all 280 apartments at Lansdowne Gate, a pioneering low energy scheme Cosgraves built in 2005. He had to go out on a limb to do so – the technology wasn’t mentioned in the 2002 edition of Technical Guidance Document F, the building regulations compliance document for ventilation

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systems. A senior official in the department’s housing section wasn’t keen, according to Cosgrave. “He wanted me to have heat recovery and put vents in the walls.” Thankfully Cosgrave managed to bring the department around. Chris Halligan of Lindab, who provided the MVHR units throughout Honey Park and Cualanor, explains how the systems work: constantly supplying and extracting air at a low level, but boosted as required – either by an in-built humidity stat or a wired function triggered by the bathroom light coming on. “The integral humidity sensor increases speed in proportion to relative humidity levels, saving energy and reducing noise,” he says. “The sensor also reacts to small but rapid increases in humidity, even if the normal trigger threshold is not reached. This unique feature ensures adequate ventilation. The night time relative humidity setback feature suppresses nuisance tripping as humidity gradually increases with falling

top A pair of townhouses at Fairway Drive, Cualanor, one of the newest phases at the development; bottom Mick Cosgrave of Cosgrave Developments.

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temperature.” Summer bypass – where the ventilation system bypasses the heat exchanger – is operated by an internal damper when the external temperature is below the internal temperature, and the internal temperature is too high. “The bypass opens and allows the cooler outside air to help cool the dwelling,” says Halligan. The systems also feature evening and night-time purge modes, which again boost the ventilation rate when indoor temperatures are too high, though users can turn off the boost function. From my personal experience, the seamlessness of the ventilation system’s operation has been a real boon: you just leave it alone, and it does its thing. “That’s one thing I learned from the Passive House Institute,” says Mick Cosgrave. “I asked them how do you control it? They said it’s very simple: you set it up, and it’s on. If somebody wants to open the window they open it, if it’s too warm. You don’t give people the option to [mess it up]. Keep it simple.” Cosgrave speaks from experience: at Lansdowne Gate, where the developer was managing the rental properties before ultimately selling the scheme, user behaviour issues led to call backs over mould problems in a couple of the apartments. “The day you go in, everything is working, because they turned it back on. For the cost of running it, it’s something like 50c per day. These people were turning it off thinking they were saving money, and it’s the most dangerous thing they did because so little air was coming in.” Cosgrave learned from the experience. When we moved in to our apartment we were confronted by a sign next to the machine warning starkly never to turn it off, and Cosgraves provided a manual for the apartment, explaining how everything worked. Our system has worked well ever since, although it is overdue a filter change. Combined heat & power Heat recovery ventilation wasn’t the only innovative technology Cosgrave used at Lansdowne Gate: the 280 apartments were heated by a district heating system, with a centralised boiler house sending heat to each unit. Fresh from his trip to the Passive House Institute with services engineer Pat Dunphy, Cosgrave put in a system capable of delivering 7.5 kW of heat per unit for space heating and hot water, which post occupancy

I value having all of this nature on my doorstep.

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top The renewable energy requirement in Part L is satisfied by solar PV arrays on the houses in both developments; bottom electric vehicles (EVs) are becoming a common sight in the two schemes, with several charge points installed in the underground car parks of the apartment buildings and high-speed chargers next to a GoCar car sharing club hub at the shopping centre.

monitoring showed was overkill. “We ended up putting 10 modular boilers in when we could have done it with six,” says Cosgrave. When Pat Dunphy retired towards the tail end of the Lansdowne Gate project, Cosgrave approached a number of the country’s best known M&E consultants about designing the heating systems for Honey Park. “We gave them a budget of 7.5 kW per unit for the heat load on all the apartments and the houses. They came in at between 16 and 21 kW.” Why build in such redundancy? “It’s the engineer’s mantra of looking at it rather than looking for it,” says Richard McElligott, who came onboard with a much more streamlined approach. “As the blocks have come along here, we’ve tried to lower the installed capacity. So when we go and do a block of 150 or 160 apartments, we’re now putting in between 2.5 and 3 kW of capacity or less per unit.” It’s a major reduction, made possible by a more nuanced understanding of occupant behaviour, by the inherent efficiency of apartments – which have less external surface area for heat loss than other dwelling types – and the fact that Cosgrave’s insulation and airtightness specs are now approaching passive house levels. Does that mean space heating demand has been close to eradicated? “Oh completely,” says McElligott. “During the day the trickle demand ambient load is very low. You basically get a spike in the morning

– absolutely consistent as clockwork – for about an hour and a half every morning where it’ll jump up, and you get a similar one in the evening. Other than that it’s really, really low.” The apartment buildings are heated by Buderus condensing gas boilers working in tandem with a bank of Dachs combined heat and power units, supplied by Glenergy, which cover about 40% of the heat load while providing electricity for landlord areas. While the renewable energy requirement in Part L is satisfied by solar PV arrays on the houses at Honey Park and Cualanor, the CHP units fulfil this role in the apartments, given that TGD L permits the use of CHP systems as an alternative means of satisfying the renewable energy requirement. According to Fintan Lyons, managing director of Kaizen Energy, who manage the district heating systems in the various apartment buildings at the two schemes, the approach is meticulous: “During concept design each and every system is looked at in detail to see how improvements can be made to ensure the right equipment is sized and selected,” he says. “Our operational strategies are agreed and implemented during commissioning to ensure network return temperatures are optimized to 40 degrees or lower throughout the year. These low return temperatures allow the generation equipment – boilers and CHP – to operate in


CASE STUDY

DUN LAOGHAIRE

above The internal courtyard in the Neptune apartment building; below the apartments are ventilated via Vent Axia heat recovery ventilation systems - which include prominent signs warning occupants not to switch the units off.

SELECTED PROJECT DETAILS Main contractor/developer: Cosgrave Group Architects: McCrossan O’Rourke Manning Structural engineers: DBFL M&E engineer/energy consultant: McElligott Consulting Engineers Ltd. Landscaping contractor: Carrig Landscapes Airtightness testers: Greenbuild Insulation/airtightness contractor: Usher Insulations Heating contractor (apartments): Kaizen Energy Prepaid heating system (apartments): Prepago CHP: Glenergy Condensing boilers (apartments & houses): C&F Quadrant PV arrays (houses): Coolair District heating consumer units (apartments): Danfoss MVHR systems: Lindab Airtightness membranes: Siga/Isover Mineral wool insulation: Isover PIR insulation: Xtratherm/Kingspan Windows: Wright Window Systems Roof windows (houses): Velux

fully condensing mode, thereby maximising system efficiencies. “All network pumps operate in variable speed based on the network [ie customer] demand. The CHPs operate 15 hours per day to power the landlord electrical services such as basement lighting and pumps. The CHP operation is optimised to offset expensive daytime electricity and delivers free heat into the heating system for residential customers so it’s a win-win for both the residential customer and management company.” The net result? “The systems installed in Honey Park are amongst the most efficient district heating systems currently operating in the country,” says Lyons. “I am able to say this with confidence as we would operate the majority of the systems in the country.” Before the recession hit, Cosgrave had plans to have a centralised plant room heating the entire development – plans that were ultimately dropped, and which fell out of favour when the apartment buildings were sold to different investors. The houses instead have individual Glow-worm gas boilers, with Cosgrave yet to be convinced about the long-term performance of heat pumps, in spite of their widespread uptake across the industry in Ireland in recent years. “In 20 years’ time, that boiler will still work,” he says. “And you’re not going to get a bill of five grand to replace it in ten years’ time.” Cosgrave swears by Glow-worm boilers in particular. “Glow-worm have an all-Ireland seven-hour replacement service on the [circuit] boards, and it costs €150 for a board that you can get anywhere. You go for any of the other brands which you’d say might be posher – you’d pay €500-600 for a board. It’s all to do with minimising the lifetime costs to the end user.” For similar reasons of reliability, Cosgrave opted for Danfoss hydraulic heat interface units for apartments, rather than more complex digital units. How do the apartments perform in summer? Last year – which was one of the hottest summers on record in Ireland – some of our neighbours found it a little too warm,

but our apartment held up well. Our main living space happens to be north-facing, but both bedrooms are south-facing, and the temperatures crept a little over 25C at times. The stairwell and corridors outside apartments do get warm at times. This may be due to high levels of glazing in the stairwell and heat loss from the centralised heating pipework – insulated pipework will still lose heat, due to the constant supply of hot water it holds. That also means it can take a while running the tap before the water gets cold. Penthouses aside, many of the apartments are externally shaded by balconies, and all windows feature internal venetian blinds which – as a London Southbank monitoring study published in Issue 26 of Passive House Plus showed – can deliver relatively significant temperature drops. But Mick Cosgrave says overheating is an issue that the group is looking at – wrestling the structural implications and thermal bridging of external shading against the daylighting requirements that inform glazing ratios, etc. In the overall context, these are fairly small quibbles. Ireland’s largest A-rated development to date – or A-rated neighbourhood, if you will – performs well in energy performance terms, but it succeeds on many other levels, and dispels the notion that being green involves sacrifice, self-denial and a decline in living standards. Honey Park and Cualanor are an important example of the benefits – the delight even – that sustainable places can bring. Places where people don’t have to waste precious time in traffic just to survive. Places with well-conceived public spaces that help engender a sense of community and encourage children to interact with each other and nature. Places that people would want to live in even if they couldn’t care less about the environment. Places that make it easy to be green.

Read more about this project in detail

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DUN LAOGHAIRE

CASE STUDY

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CERTIFICATE 18/5505

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CASE STUDY

DUN LAOGHAIRE

IN DETAIL The following information relates to Charlotte and Leona apartment buildings (two adjacent blocks of apartments with 319 units in total), unless denoted (*) for whole Honey Park/ Cualanor scheme or otherwise stated. Building type: 5/6 storey apartment blocks with circa 7 cores each. The units are each over a basement and constructed with masonry walls with an internal insulation liner. Location*: Honey Park & Cualanor, Dún Laoghaire, Co Dublin Budget: Construction costs are circa €70M for the two blocks Space heating demand: Typically, less than 10 kWh/m2/yr, based on metered heat usage over the 12 months of operation less the hot water demand. Energy performance coefficient (EPC): Averaging about 0.36 Carbon performance coefficient (CPC): Values including 0.331 (mid terrace house at Abbot Drive), 0.306 (mid floor apartment at Eustace Court) & 0.221 (apartment in Fairways building). BER*: Majority of development A2 rated. Some ground and top floor units coming in at A3. Airtightness: Generally, circa 1.5 m3/hr/m2 at 50 Pa. Thermal bridging: ACD default value of 0.08 used for DEAP calculations. However nearly all construction details were thermally

modelled and if used for the apartments would deliver a thermal bridging factor of 0.06 on average. It has been noted that the gains in the DEAP programme are nominal at this level and only effect the losses associated with space heating which are working out at less than 30% of the thermal footprint of each unit. Energy bills (measured)*: In the apartments in Honey Park & Cualanor the cost of heat energy for space heating & hot water, off the district heating system works out at circa €620 a year, covering the energy, standing charge, sinking fund and VAT costs per unit.

Heating systems (apartment buildings): Centralised district heating system. 3 mini CHP engines are the lead heat source with a pair of boilers (duty/ assist). All gas fired. Ring main around the basement with a set of rising mains per core. Individual branch on each landing piped to a heat interface unit in each apartment. The heat interface units have heat meters and an instantaneous heat exchanger for hot water generation. The water is direct fed to the rads in the apartment. Heating systems (houses): Glow-worm Flexicon modulating condensing gas boilers – typically 90.4% efficient, 18 to 20kW boilers.

GROUND FLOOR Apartment buildings: 700 mm thick podium flat slab with 120 mm PIR. U-value: 0.14 W/m2K House floors: Strip foundations with 120mm Xtratherm insulation. U-value: 0.11-0.13

Ventilation*: Vent Axia Sentinel units throughout houses and apartments, with Kinetic Advanced units in Eustace, Charlotte and Leona, with an Appendix Q efficiency (2012) of 93% and 0.66 W/l/s.

Walls*: Brick outer leaf, cavity, block, internal 120 mm PIR board, service cavity and a plasterboard liner. U-value: 0.15-0.16 W/m2K.

Water: All water in apartments supplied off a central water tank and booster pump set which allows for better maintenance of the tanks and less energy used to pump the water. Low capacity cisterns used also.

Apartment roofs: Flat roof with PIR insulation over a concrete deck and a Paralon / Trocal liner. U-value: 0.16 W/m2K. House roofs: Cold roofs with 300 mm of mineral wool insulation on the attic floor – cross laid to cover joists; on airtight membrane on plasterboard. U-values: 0.14 W/m2K. Windows*: Thermally broken Kommerling C70 PVC frames with Diamond Glass double glazed units, with a 16 mm gap. U-value: 0.142 W/m2K. AMS triple glazed aluminium thermally broken system in penthouses.

MICROGENERATION Apartments: Dachs CHP units generate electricity for landlord areas in apartments, while generating heat for district heating system. Houses: Coolair 4 panel solar PV arrays – rising incrementally from an output of 225 to 300 Wp output per panel from the first phases at Honey Park to the last phase at Cualanor – meaning total outputs of 900 Wp to 1.2 kWp per house to cover background loads, with excess spilling into the grid.

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PA R T L & F

INSIGHT

LOW ENERGY GARDEN BUILDING UNMOVED BY WEATHER EXTREMES A new garden office and show room provides a showcase for how heat pump and heat recovery ventilation technology — when combined with a fabric-first approach to construction — can provide a consistently comfortable and healthy indoor environment, no matter what the weather outside.

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INSIGHT

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new office and showroom in Horsham, West Sussex aims to neatly demonstrate just how well passive house principles of building, heating and ventilation work together in practice. But it was built in slightly unusual circumstances. Speaking to Passive House Plus, Nilan UK managing director Stuart Laughton explains the challenge the company faced in establishing a suitable show home to demonstrate how its products work. The company is well known as one of the leading suppliers of heating and ventilation systems for passive houses in the UK. “Well, when you look at a business and think about how to make things easier, your office being a showpiece for what you do is a natural angle,” he says. “We have a rather large building hiding in the Sussex countryside for all our kit, but that’s far too cold and draughty in the winter for an office. We had tried a serviced office complex in town, but it was way too expensive and we weren’t allowed to put any of our kit in there, and I also didn’t think it made us stand out in any way.” So, Laughton turned his attention to the idea of a garden room to serve as an office and showcase how the company’s products work. “None of the standard garden room companies really understood why I was banging on about insulation and airtightness.” He then spoke to a local builder, Edenrbriar Ltd, who were in the middle of finishing a large house that Nilan were installing an MVHR system in. “They gave us a price to erect the timber frame, build the slab and put the roof on, and the rest we planned on doing ourselves,” he says. Because of the proximity of the Victorian walls of the house, it was not possible to dig down far enough to create a floating raft

without adding additional structural support to the walls (or having them fall in). So, the base of the new garden ‘room’ is re-bar and concrete, while the walls are constructed from timber frame cassettes (with 140 mm rigid insulation between) and lined internally with OSB, airtightness membrane, 25 mm battens insulated with sheep wool and multi-foil layer, then plasterboard and skim. The roof is comprised of a grey metal standing seam roof with 50 mm rigid insulation beneath, followed below by 9 mm OSB, 200 mm wool between the rafters, an airtightness layer, multi-foil insulation, plasterboard and skim. “The thing we knew we had to get really busy on though was the airtightness as we would be heating and cooling via the air.” Careful attention to taping with Tescon Vana tape ultimately paid off when the building scored 0.7 air changes per hour at 50 Pascals on its airtightness test. “I was quietly almost celebrating when the ‘Beast from the East’ came as we weren’t remotely finished, not even with the membrane, but nonetheless a 1kw fan heater managed to keep the temperature inside at 14C even after it hit -8C during the night with snow on the ground.” Perhaps not surprisingly, Nilan opted to install one of its flagship Nilan Compact P units. The Compact P combines a mechanical ventilation with heat recovery unit and air-to-air heat pump to deliver fresh air, space heating and cooling, and hot water production. Occasional transport “mishaps” meant that one Compact P unit was going spare. “We had no idea what heat losses for the building would be, so we also purchased from Nilan an item sold on the Finnish market, the Nilan EK or electric kettle. This is basically a small electric boiler for wet underfloor heating. I don’t

GARDEN BUILDING

like the idea of an electric duct heater drying out air coming into the building in winter, and besides, underfloor heating offers such supreme comfort.” He also opted to install a pulse energy meter on the Nilan , the electric kettle and one for the duct pre-heater, to monitor usage in detail. He reports that in total, the building consumed 2,382 kWh for all space heating and cooling, hot water and ventilation duties in the period from May 2018 to May 2019, keeping the indoor temperature between 20 and 23C, as well maintaining a tank of domestic hot water, regardless of outdoor temperatures. The cost for this was £309.66, or 84p per day. “Bear in mind we also had the factor of doors being open in the hot and cold weather as internal construction was still being carried out by my brother Simon [Nilan UK’s operations director] and I as well,” Laughton. “Being a Nilan partner of over a decade standing I have clearly always believed in the product, but to live with one in an airtight building really is something else. I remember a long time ago Torben Andersen, Nilan’s founder and CEO, telling me ‘we don’t sell heating or ventilation, we manufacture comfort’ — and it’s true.” “In a not very exciting way, once commissioned correctly and within a decent building fabric, you never feel hot, you never feel cold, there are no dead spots and the only time I touch the controls are when we are doing demos to potential clients or visiting engineers.” “Everyone is welcome to visit our simulation via appointment, pop in for coffee and a bacon roll. No one has ever left without the feeling of gained knowledge, and if you’ve visited when the weather is extremely hot or extremely cold, amazement has always been the buzzword.”

above Inside the new Nilan UK office and garden showroom; right Graphs showing the temperature of air extracted from the building remaining stable and comfortable during periods of very cold and hot weather.

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LONG TERM PH

INSIGHT

PASSIVE RESISTANCE HOW A R E TH E F IRST PAS S IVE H O US E S FARING TO DAY ?

Photo by Peter Cook

One of the most common questions asked of passive buildings is how they will perform in the long-term — will the building still be airtight in 20 years, and will the heat recovery ventilation still be working? Recent testing and evaluation of passive houses built in the 1990s and 2000s sheds new and convincing light on these questions.

Words by John Cradden

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ver since the first passive houses were built over 25 years ago, passive design principles have very slowly but surely entered the mainstream. But despite the well-documented and proven advantages of the passive house standard and its growing influence on mainstream construction, its widespread adoption still seems some way off. There are probably various reasons for this, despite the passive house advocacy toolkit

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being well stocked with proven benefits: better air quality, superior comfort, low running costs and reduced environmental impact. But now this toolkit looks set to gain a critical new weapon in its arsenal: long-term durability. Up to relatively recently, it has not strictly been possible to confidently answer questions about how passive house performance holds up over time. Given that there are a number of essential

elements to a typical certified building (well-insulated building fabric, airtight and thermal bridge-free constructions, triple glazed windows and mechanical ventilation) that all need to perform within a narrow margin of efficiency, a deterioration in the performance of any single element would be a bit of a slap in the face to the standard. Of course passive houses don’t require much in the way of mechanical systems — bar heat recovery ventilation, at least in cooler climates — so there’s not really much to go wrong. Where things could go awry, in theory, is if essential building fabric components, such as airtightness tape, prove to be poor quality, or if less than suitable component choices are made, or if there is poor attention to detail when the building is constructed – although the requirements to provide evidence of how the building is built for certified passive houses, and the scrutiny of the stringent airtightness test requirements should provide less scope for poor quality.


INSIGHT

with EPS, in 2005, and has since upgraded the heating system from a wood pellet boiler to an air source heat pump, and put in solar PV panels. The house was tested in 2017 by energy-efficiency consultant, academic and passive house expert Dr Shane Colclough, who measured the performance of the house against key passive house benchmarks, including primary energy, space heating demand, domestic hot water, winter indoor temperature, overheating, C02 levels and humidity. Colclough found that the house was still performing very close to all benchmarks and in some cases better — and all without factoring in the solar PV inputs, as they were

not included in the house’s original PHPP (passive house software) calculations. “What was really fascinating was that all the numbers came in pretty much on the button,” says O’Leary. “I was delighted to see it out because I felt myself over the years that the house was performing very well but I had no quantitative data to back that up... basically Shane was able to prove that the house was sort of doing exactly as it had been specified to do.” Tirimani, meanwhile, has kept an extensive record of the long-term performance of Y Foel, completed in 2009, which he has documented on his blog Passivebuild.co.uk, but it has also been independently airtightness tested, and

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Nonetheless, recent efforts have sought to fill in this last piece of the puzzle by assessing the performance and durability of some of the earliest passive houses. Among them are the homes of Tomas O’Leary in Wicklow and Mark Tirimani in Wales, the first certified passive houses in Ireland and the UK respectively. O’Leary is the leading passive house expert behind MosArt Architects and the Passive House Academy, while Tirimani is a self-builder and regular speaker at conferences on his long-term monitoring of Y Foel, a charming timberframed two-storey house in Machynlleth. O’Leary built his 4,000 square foot house, essentially a concrete shell externally insulated

LONG TERM PH

Monitoring years in 1st Passive House Darmstadt

above Y Foel, Mark Tirimani’s Welsh passive house was built in 2009; bottom left monitoring of energy consumption over 24 years from the first ever passive houses in Darmstadt; bottom right Tomas O’Leary’s passive house in Wicklow was Ireland’s first, finished in 2005; facing page the world’s first passive house scheme, a four-unit residential building in Darmstadt built in 1990

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LONG TERM PH

INSIGHT

The integrity of the airtightness and insulation also remained unaffected even by several small earthquakes. 1

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Images from the recent re-testing & evaluation of the first ever passive houses in Darmstadt, including: 1, 2 & 3 removing EPS insulation and plaster from the walls to examine their condition after 28 years; 4 200 litres of air was collected on gelatin filters at air supply outlets by means of a filtration sampler; 5 heat-flow measurement device for evaluation of the thermal performance of the windows; 6 visual inspection inside the MVHR ductwork.

also found to be performing just as well as it did when first certified. Tirimani and his wife are often asked to give their views about having lived in their house for well over ten years, and he says: “we just sum it up in one sentence and we say the same thing again and again: it’s far exceeded our expectations and it’s incredibly stable and I think the stability of living in our passive house is something we weren’t prepared for.” The world’s first passive houses But probably the most significant and extensive of all these recent re-tests is that of the very first passive house development in Kranichstein, a district in the city of Darmstadt, Germany, which was built in 1990. It’s a three-storey, four-unit terraced house, and one of the four units is owned and occupied by the family of Prof. Wolfgang Feist, a physicist and one of the co-originators of the

66 | passivehouseplus.co.uk | issue 31

passive house concept as well as the founder of the Passive House Institute. Being essentially a prototype building and the first showcase for the passive house concept, Feist clearly foresaw the need to monitor the performance of the building over time, so it was fitted with a comprehensive array of some 200 sensors, including temperature sensors, pyranometers, a pyrgeometer, hygrometers, heat flow sensors, heat meters and electricity meters. With data logged over 25 years, Feist reports that the energy consumption of all four units (which have natural gas heating systems) has remained stable at an average of 8.4 kWh per metre square per year. “The overall efficiency of the building is thus not deteriorating, nor are there palpable changes in user behaviour,” say Feist and fellow researchers Rainer Pfluger and Wolfgang Hasper, who recently published research on the long-term

performance and durability of the dwellings. The building itself is of a straightforward design, a simple box with masonry walls made of lime sandstone, with gypsum plaster on the inside. This is widely regarded as a very robust combination, so the testers chose not to test it. The two layers of EPS external insulation are topped by a mineral plaster exterior, which tends to be regarded as having a shorter shelf life, according to the authors. A visual inspection showed the plaster had turned grey in colour but remained intact everywhere, requiring no more than a cosmetic touch-up. But just to be sure, they cut out a sample of the plaster for lab testing. This showed “no indications of fissures or any imperfect adhesion of the plaster to the insulation layer”. They concluded: “Highly insulated wall structures can be built in masonry construction with a lot of wall materials; these are inexpensive with EIFS [external insulation and finish systems]. The systems remain effective, dry and weatherproof using an exterior mineral plaster reinforced with a fibreglass tissue. Such plaster can be expected to remain in use for more than 50 years even in areas with harsh climatic conditions; the insulation layers are robust for even longer.” In terms of the roof structure, one potential issue was that Kranichstein local building regulations called for a green roof, i.e. a roof covered with vegetation. Lloyd Alter, design editor and writer for Treehugger.com, commented that with polyethylene vapour barriers and practically no ventilation of the roof structure, he would have expected the testers to find a “bunch of soggy insulation” after 25 years, but instead the insulation was still in excellent condition thanks to it being highly airtight and well insulated. Ensuring precipitation drains off the roof is also crucial to protect it, the authors say. Having said that, they would recommend a ventilated cover of some kind if they were undertaking the same project again, but all the same they say that “there are practically no limits to the durability of such a highly insulated structure”. Meanwhile the researchers couldn’t trace any new thermal bridges or heat losses, while a repeat of the airtightness test showed only the window lip seals to have deteriorated; when these were renewed the exact original airtightness result (0.21 ACH at 50 Pascals pressure) was once again achieved. All the other critical connection points proved to be still as airtight as they were 25 years ago. The integrity of the airtightness and insula-


INSIGHT

tion also remained unaffected even by several small earthquakes in the area, including a magnitude 4.2 one in May 2014. Looking at the triple glazed windows, the loss of insulating krypton gas was negligible and the insulation value of the windows was still intact. This is all the more remarkable because the windows were custom-made during construction, given the lack of triple glazing on the market at the time. But the authors note that sensitivity to gas losses drops considerably if argon is used instead of krypton, and the distance between panes is increased to from 8 mm to 15 mm. The project was one of the first where the windows were mounted in the building’s insulation layer, and being triple glazed they were always going to be warm on the inside, so unlikely to be affected by condensation-related rot. On the ventilation side – and certainly one area that might be expected to show some noticeable deterioration — an examination showed that, with the exception of the moving parts such as filters and fans, nothing needed replacing and the duct system was clean after 25 years of constant use. “There is no reason why the basic components (ducts, cases, filter boxes and counter-flow heat exchangers) could not be used for 50 years. Only the ventilators have a service life of 15 to 20 years; replacing them costs around €500,” the authors write. The filters can be changed easily and the ducts only needed cleaning once every ten years. “In the past, every now and then the passive house concept has been challenged according to a theme: ‘it’s all very well, but it will not last!’”, Wolfgang Hasper wrote in an email to Passive House Plus. “The research and continual monitoring in Kranichstein now proves this clearly wrong and we can

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consider this issue settled.” And of course, long-term durability means reduced life cycle and maintenance costs too. Part of the key to the success of this particular project was the careful choice of commonly available building materials. “This will probably hold true for other times and regions where passive house may be new, but careful design and construction will yield reliable and lasting results,” says Hasper. So what state does Hasper expect the building to be in 25 years from now? “We expect the building fabric to be as found after 25 years; a new coat of paint might be desirable for aesthetical reasons. The windowpanes will probably want replacement. MVHR fans operating now are a very early generation of EC-motor driven devices and might need replacement in a few years. Ducting, heat exchanger etc will still be useful and, as far as we found now, probably need no cleaning either.” Tomas O’Leary is among the many visitors who have visited Feist’s house since 1991, and he praises the physicist’s generosity in allowing testers to dismantle and cut bits out of the building on the 25th anniversary test. “I think in a very modest way it was kind of like fingers up to the cynics who thought the airtightness wouldn’t last, or the ventilation system would pack up and die or whatever.” O’Leary says that any deterioration in the condition of his house after 15 years is down to the same normal interior wear and tear you’d expect a young family of five to inflict. On the outside, his oak windows don’t have an aluminium finish so they have needed some re-oiling and varnishing, while the building’s strong external colours have faded a little, but this is not something a new visitor would pick up on. Even with a cat and a dog sharing the house with three young

LONG TERM PH

girls, the ventilation ducts were found to be free of dirt or dust. There was an issue with airtightness around the bottom of one floor-to-ceiling window that was discovered about two years after moving in, but a quick investigation found that a builder had applied household ducting tape rather than airtightness tape around a third of the window frame. “It proves the point that if you don’t use good materials and they’re not applied correctly....like we visit passive house projects under construction and people are trying to apply tape to dusty floors, and at the risk of embarrassing the contractor you’re going along and you’re pulling at the tape and it’s coming away from the floor in places.” Tirimani has also studied the paper on the re-testing and evaluation of Wolfgang Feist’s house. Indeed, having previously lived in Germany for some 13 years, he was able to educate himself back in the noughties about PHPP using information from the Passive House Institute at a time when there were few English translations available. He admits it took a while to fully comprehend exactly why he had to spend such a high proportion of his fabric budget on the windows. “But I had faith in it...and we ended up with a solid building fabric and high-quality components, but nothing exotic.” While describing the integrity of his cellulose-insulated, timber-frame building structure, which is finished externally with a mixture of cladding and render, he says the “things that will let go first will be slates that are damaged either through trees falling on them or the weather”. Barring a tornado or an earthquake, he says, “you’d measure the lifespan of this building in hundreds of years, not 40 or 50.”

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-0 1 13 -20 -0 16 1 14 -201 -0 6 1 15 -20 -0 16 1 16 -20 -0 16 1 17- -201 01 6 18 -20 -0 16 1 19 -20 -0 16 20 1-20 -0 16 1 21 -20 -0 16 22 1-20 -0 16 23 1-20 -0 16 24 1-20 -0 16 25 1-20 -0 16 26 1-20 -0 16 27 1-20 -0 16 28 1-20 -0 16 29 1-20 -0 16 30 1-20 -0 16 1 31 -20 -0 16 01 1-20 -0 16 02 2-20 -0 16 03 2-20 -0 16 04 2-20 -0 16 05 2-20 -0 16 06 2-20 -0 16 07 2-20 -0 16 08 2-20 -0 16 09 2-20 -0 16 2 10 -20 -0 16 2 11- -20 02 16 12 -20 -0 16 2 13 -20 -0 16 2 14 -20 -0 16 220 16

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left Analysis of the Krannichstein passive house reveals indoor levels of carbon dioxide and relative humidity are in the healthy range 28 years after completion; testing of Tomas O Leary’s passive house from 2009 including top right and bottom right a thermal camera image during airtightness testing revealing an area of heat loss.

Photography by Passive House Institute, Mark Tirimani, Shane Colclough, Tomas O’Leary

ph+ | long term ph insight | 67


MARKETPLACE

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

Marketplace News Kingspan up for green manufacturing award

K

ingspan Insulated Panels and Kingspan Insulation have jointly been shortlisted for the sustainable manufacturing award at the prestigious The Manufacturer MX Awards, recognising the company’s “commitment to sustainable practice at all levels of their business”. Almost 50 of Britain’s top manufacturing companies have made it through to the finals of one of the UK’s largest and most rigorous manufacturing industry awards programme. The awards ceremony will take place on 14 November at the Exhibition Centre in Liverpool, rounding off Digital Manufacturing Week. A statement from Kingspan read: “In the UK, both Kingspan Insulation and Kingspan Insulated Panels work hard to implement clear sustainable and responsible business practices, from reducing the environmental

impact of their manufacturing processes to engaging with external stakeholders to ensure their passion is translated into industry-wide action. “Central to this strategy is also its commitment to become a net-zero energy (NZE) company by 2020. NZE means that in a given year, it must be energy neutral on an aggregate basis across its entire estate. It is a global effort, covering 129 sites and over 14,000 employees. It has now reached over 75% NZE and is well on course to achieve the NZE goal by 2020.” “Of course, sustainability is not just about looking inwardly. Both divisions take an active role in the communities surrounding their sites, proactively communicating their actions, consulting with them on local issues and helping them to improve the local area through various division-run schemes.” •

(above) Kingspan’s global head office and innovation centre in Co Cavan, Ireland – a 1969 building which the company has deep retrofitted to net zero energy levels.

Ecological announce thermal modelling service

Ecological Building Systems’ technical team member & NSAI-approved thermal modeller Joe Fitzgerald, speaking about heat loss and mould growth through thermal bridges at a CPD event on nearly zero energy building earlier this year.

E

cological Building Systems have announced the addition of a new thermal modelling service to their existing array of technical services. Ecological technical team member Joe Fitzgerald recently successfully completed the National Standards Authority of Ireland (NSAI) approved thermal modellers examination in Dublin Technological University. Fitzgerald is now listed on the NSAI thermal modellers register. Niall Crosson, group technical manager

68 | passivehouseplus.co.uk | issue 31

at Ecological Building Systems commented: “With the introduction of NZEB, limiting thermal bridging is pivotal to attain compliance in domestic and non-domestic buildings. Ecological can now model and calculate U-values of complex 3D building elements in accordance with EN ISO 6946, as well as modelling and calculating the linear thermal transmittance of thermal bridges at building junctions in accordance with EN ISO 10211-1 and BR 497.” He continued: “Ecological also provide

recommendations on what measures can be taken to improve the thermal bridging performance of key junctions in order to achieve ACD status utilising our suite of thermal bridge solution products including BOSIG PHONOTHERM, GUTEX woodfibre and DIASEN thermal plasters to name a few. This compliments our market leading technical support service which extends to hygrothermal and U-value assessments, as well as our extensive suite of CPD presentations promoting better building putting the fabric first.” On receiving his qualification, Joe Fitzgerald noted: “This service allows us to work closely with designers looking to value engineer building details and complex junctions. By optimising these junctions through thermal modelling at the design stage we can offer true value to a project, greatly reducing the likelihood of a performance gap by accounting for a true reflection of heat loss in buildings.” Ecological Building Systems are available to help guide building professionals through design detailing, products and advice on installation. Further information on the full range of products and services can be found on www.ecologicalbuildingsystems.com. •


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

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Green Building Store Future Found gets launches new energy BBA Cert for insulated model service foundation system G

reen Building Store has announced the launch of a new service that is now included at no extra charge in its product packages. Green Building Store customers purchasing triple glazed windows or doors together with an MVHR system can now avail of energy performance modelling of their building at no extra charge, subject to terms and conditions. “The service is designed to help the company’s clients to understand the energy performance of their project and to achieve the best in energy efficiency,” said Green Building Store director Bill Butcher. “This is part of Green Building Store’s commitment to helping its customers make their buildings energy efficient and ensure they find the most appropriate products for their project. The service involves the modelling of clients’ projects in designPH, to provide a basic model of their house in the Passive House Planning Package PHPP.” The service is particularly aimed at those concerned with energy efficiency, but not intending to reach advanced energy standards, such as passive house or AECB building standard. It will give a good indication of the performance of the building without the fully detailed modelling in PHPP required for those standards. Green Building Store said the service will help its customers:

B

uild-Lite, the leading manufacturer and supplier of innovative building products for low energy buildings, has announced that its Future Found insulated foundation system has received BBA certification. Future Found is a trenchless foundation system, manufactured in the UK, that uses high-density EPS insulation. Future Found is designed and cut to suit each individual project. The product arrives on site as a fully engineered, ready-made EPS formwork that fits together. This outline then remains in the ground, and concrete is poured in one operation to create an energy efficient slab foundation that is capable of delivering passive house U-values and thermal bridging standards. “Future Found is quick and easy to install, only three days to fit for a standard three-bedroom house,” Alan Parkes of Build-Lite told Passive House Plus. “It also reduces machine time required on site as there are no trenches to be excavated, no soils away and 40% less concrete is used. It means the builder saves on both installation and material costs, and the homeowners have significantly reduced heating bills.” The company’s BBA certificate follows an intensive period of testing of the system that began in 2015 at an independent test facility in Stoke, according to Parkes. “We asked for all tests on the system to be done until destruction, but this could not be done as Future Found would not fail, which was fantastic.” The BBA cert was awarded this year following a further period of review, as well as further testing of all the fixings, and the development of quality manufacturing and site installation plans for the product. Parkes said that the system has now been used all over the UK and Ireland, and that BBA certification will now make it suitable for specification by larger housing developers. For more information see www.build-liteuk.co.uk. •

• fi  nd the projected energy performance of their self-build project; • u  nderstand any overheating issues so that they can be addressed at the design stage; • p  redict heating costs and enable customers to choose the most suitably sized heating system for their project; • c hoose appropriate products – for instance to work out which windows (and U-values) are best for the project; • d  iscover if the building has scope to achieve building standards such as AECB, Enerphit or passive house. For more information go to: www.greenbuildingstore.co.uk/ energy-performance-modelling/ • (below) Model of a passive house in designPH, the popular plug-in for SketchUp.

(above) The Future Found insulated foundation system.

ph+ | marketplace | 69


MARKETPLACE

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

“I wish this course had been available at the start of my career” Daren, Architectural Technologist

CarbonLite Retrofit Training The UK’s leading advanced domestic retrofit e-learning course 130 hours of in-depth, advanced-level learning

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• Gain an expert-level technical understanding of domestic retrofit • Earn 35 Passivhaus Institute credit points • Join at a date convenient to you • Optional, pay-as-you-go, expert-led tutorials (£25 each) • Exclusive to AECB members for only £410 +VAT Join the AECB from as little as £36. Members of the Passivhaus Trust receive a 20% discount on joining fee. For more details visit www.aecb.net

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Introduction to CarbonLite Retrofit Buildings in the UK Climate The UK Housing Stock Energy in Buildings Moisture in Buildings Monitored Case Studies and Data Building Services for Retrofit Retrofit Investment Appraisals and 70CLR | passivehouseplus.co.uk Cost Modelling | issue 31

Book your place today! To book your place, or to find out more details, visit www.aecb.net/carbonlite/ carbonlite-retrofit-training-course the Association for Environment Conscious Building AECB, PO Box 32, Llandysul, UK SA44 5ZA t: 0845 456 9773 e: membership@aecb.net


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

MARKETPLACE

(above) A developed parcel of detached housing, typical of many developer-led projects. “In the vast majority of cases the purchaser has little or no choice over the quality of their home,” says Will Kirkman of Ecomerchant, “it is determined for them by the designer and constructor in line with regs.”

UK HOUSING MARKET MUST START DEMANDING MUCH HIGHER QUALITY – ECOMERCHANT

T

he entire UK housing market — from self-builders and house buyers through to large-scale developers, housing associations and local authorities — must start demanding a much higher level of quality from new homes in order to ensure the market delivers buildings that are genuinely healthy, sustainable and low energy. That is according to Will Kirkman, managing director of leading sustainable building product supplier Ecomerchant. “My plea to the market would be that we really need to build better homes. We need the market to become better educated, and we need it to demand better quality,” he said. “The current housing crisis in the UK is not so much a question of a lack of dwellings, but a problem of affordability and quality, exacerbated by a speculative model that drives up prices and keeps standards at the lowest required in law. There are plenty of homes out there, but they are either unaffordable or of poor quality or both.” Kirkman says the current model for delivering new homes is flawed, with a misplaced focus on housebuilding as the only solution to the problem. He cites evidence that the provision of new housing has outstripped the growth in the number of households in England since house prices reached their low point in 1996, with similar trends apparent in Scotland and Wales, according to ‘Tacking the housing crisis: is supply the answer?’, a recent report written for the UK Collaborative Centre for Housing Evidence. But UK house prices have still grown 160 per cent in real terms since 1996, rents are

relatively high, and home ownership has fallen over the past 15 years. However, despite common perceptions, tight housing supply is not to blame, according to the report. “The result is more houses at higher prices with no real increase in quality — a double whammy for consumers,” Kirkman said. Kirkman also refers to analysis by energy expert Richard Tibehnam published in Issue 30 of Passive House Plus, which concluded that England currently has enough empty dwellings to meet supply. Tibenham wrote: “There are enough houses to go around, they’re just not distributed effectively and many are unfit for the demands of the 21st century. England has an estimated 200,000 empty properties, for example, enough to house its homeless population of 277,000.” Speaking to Passive House Plus, Kirkman echoed these sentiments: “It’s more a problem of affordability, social mobility and quality then one of numbers. Right now, the majority of people are only able to buy houses that are built to minimum standards.” Ecomerchant supply a wide range of natural insulations and other sustainable building products, all geared towards creating durable, comfortable, low energy dwellings with an emphasis on indoor air quality. However, Kirkman said that many housebuilders simply never get the option to consider such materials. “When we talk to customers who can directly influence specification, such as self-builders and those undertaking refurbishment projects, building performance

is often not a top priority, or not considered at all. In many cases architects haven’t even asked their clients if they want to build something that goes beyond building regulations. “This means that clients never even get to explore the option to use anything other than standard building materials, or consider design to exceed compliance,” he said. “Part of the issue here is perceived value and benefits — if they already think what they are getting is good enough, then why change or do something else? He continued: “Largely, in the developer-based UK model of housebuilding, any customer who demands to buy a home to more than the compliant minimum of building regulations is unusual. In the vast majority of cases the purchaser has little or no choice over the quality of their home — it is determined for them by the designer and constructor in line with regs.” “At Ecomerchant we consider the whole product supply chain from raw material production to end use, to ensure not only the lowest possible environmental impact, but also to endeavour to ensure that there are limited or no negative impacts on human health. Issues such as building durability and indoor air quality are high on our agenda. We have a proven and trusted range of products orientated around low environmental impact, energy efficiency and health. “Our team of knowledgeable staff are keen to help people build and refurbish using natural and sustainable materials where possible to create healthier, more efficient homes, schools and workplaces.” •

ph+ | marketplace | 71


MARKETPLACE

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

New airtight London apartments near completion

NBT begins merger with Soprema

N

BT, the UK supplier of Pavatex insulation and airtightness products, has completed the first phase of a merger with building products giant, Soprema. A global name in the construction supply chain, Soprema boasts 67 manufacturing sites around the world, more than 90 subsidiary companies and more than 4,000 distributors. NBT first joined the group in 2016 and the legal process of creating the new UK business has been in progress in the interim, drawing on synergies between Soprema and NBT, while ensuring that NBT retains its clear focus on delivering sustainable, robust and cost-effective solutions for the building envelope. Andrew Mitchell from NBT/Soprema explains: “We have undergone what might be called a soft merger over the past couple of years and our customers probably haven’t noticed the difference as we’ve been going through the legal, commercial and operational process of completing the new structure. “However, the integration of NBT and Soprema brings with it huge benefits for specifiers, procurement professionals, contractors and end-users as it enables a joined-up supply chain focused on best-fit and best-practice solutions for the building envelope. For specifiers it means an integrated, expert approach to delivering a project-specific solution, for procurement and construction professionals it means a rationalised, cost-effective supply chain, and for the end user it ensures buildings that will perform better and last longer.” NBT’s Pavatex range of woodfibre insulation, airtightness tapes and membranes now sit alongside a huge array of Soprema solutions, including waterproofing, roofing, solar energy, insulation and acoustics. A statement from NBT said that the company has already been pioneering envelope solutions and driving take-up of sustainable, renewable building products in the mainstream construction industry, and the company will now leverage the global capabilities of Soprema to take this vision forward. Laurent Verheyden, managing director of Soprema businesses in the UK, said: “The building envelope is becoming increasingly complex and specifiers often have to look to different suppliers for the varied elements of the build-up.” “What we can now offer is a specialism in complete envelope solutions, with hybrid systems that answer the needs of today’s construction sector, including buildability, performance and environmental goals. All of that will be backed by the warranty, technologies and expertise available from Soprema, for a high standard of support and quality assurance from first enquiry to final hand over.” •

72 | passivehouseplus.co.uk | issue 31

(above) Battens fixed to Magply boards to create a service cavity before the installation of Passive Purple liquid airtight membrane.

A

new apartment development in one of South London’s up and coming districts is making use of Magply boards’ fire resistance and other performance characteristics, as the lining to a bespoke timber frame package. The five flats are being developed on land adjacent to Peckham Rye railway station by Unboxed Homes, who have overseen all the service provisions and creation of the sub-structure. Cambridgeshire-based White Haus is the timber frame specialist that has manufactured and erected the highly energy efficient structural envelope. Crucially, given the proximity of the building to neighbouring properties, 9 mm Magply has been used to line the timber panels, before being sprayed with Passive Purple, a polymer-based liquid airtightness membrane. The purple/ white-finished Magply MgO boards are therefore the surface that purchasers are presented with to fit out according to their own specification and taste. Project manager for White Haus Tony Buck commented: “We offer clients a bespoke service for the supply and

installation of high-performance timber frames to meet various specifications — right up to passive house standard — building schools, hospitals and commercial premises as well as domestic properties. While the timber frames normally have a plywood sheathing, we choose to use Magply internally whenever there is a requirement for fire protection as it offers up to 90 minutes resistance and meets the increasing threat of arson attacks on construction projects, as well as improving fire safety throughout the life of a building. “Then, as with the Peckham development, once the 25 mm battens have been fixed to create a service cavity, we spray the surface with one of our membranes. Although this project isn’t actually passive house – which would require triple glazed windows – the sprayed PU insulation in the walls gives a U-Value of 0.15, while close fitting Magply boards and our Passive Purple membrane will give an air permeability down at 0.6 air changes per hour to work with the heat recovery ventilation system.” •


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

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www.passivehouseplus.co.uk ph+ | marketplace | 73


T O BY C A M B R AY

COLUMN

What can space travel tell us about building science? In the first instalment of his new column on building physics, Toby Cambray, co-founder of Greengauge Building Energy Consultants, takes a look at some similarities and differences between rocket science and building science.

I

n case you have been living under a lunar rock, this summer marked the 50th anniversary of the moon landings. As an engineer it’s difficult not to get excited about anything to do with space, and I’ve been thinking about what space travel has to tell us about building science. We’re often reminded that the space programme has spawned a variety of technologies that have found their way into everyday use, such as the humble post-it-note and memory foam. Some NASA technology has of course found its way into the construction industry, but dig a little deeper and the topic of space travel has some useful things to teach us about building science. It’s cold in space, right? Colder than anywhere on earth, as most articles on how astronauts stay comfortable insist. So why are the walls of various rockets and modules only 50 mm thick? The answer is counterintuitive and depends on what we mean by ‘cold’. Temperature is a quantity invented by humans to represent the average kinetic energy of a bunch of molecules. In space, no one can hear you scream, because there are no air molecules to vibrate, which also creates a conundrum when it comes to temperature, because we can’t measure or define the kinetic energy in a vacuum. If you think back to classroom physics, heat can move via convection, conduc-

is for the hot cup to radiate heat to the cold one. In space there’s mostly no objects to exchange radiation with, so it just flies away forever, and your radiative heat losses aren’t offset by gains from nearby objects at a similar temperature, as they are on earth. To solve this problem, NASA invented metalised plastic films to create a radiative barrier, and hence the ‘space blankets’ commonly distributed at mass sporting events or disaster relief situations. This technology has also been deployed with debateable efficacy in the construction industry in the form of multi-foil insulation. Unfortunately, while this works really well in a vacuum, in the presence of air convection and conduction come back into play, and the most practical solution to that is a good thickness of something fluffy. One relatively recent innovation that attempts to banish convection and conduction is that most space-age of insulation materials, the vacuum insulation panel (VIP). You’d be forgiven for thinking the VIP was a classic NASA spinout, but you would still be wrong. The main challenge with VIPs is maintaining a vacuum — one thing that, it turns out, is easier in space than on earth. This fact underpins the way the windows of the lunar and command modules work. Although the shuttle has triple glazing with some incredibly thick and special-

But what about Aerogel, I hear you cry, wasn’t that invented by NASA? Alas no, Aerogel was in fact invented in the 1930s, although it is used by NASA as a high-tech crumple zone for catching micrometeoroids undamaged for study back on earth. Indeed, as far as I know, NASA have not made any major contributions to building insulation, simply because it’s not a problem they had to solve. NASA engineers are rightly revered for their amazing accomplishments, but their impact on earth-bound low energy building is less than you might think. As they say, building physics isn’t rocket science – it’s harder! n

It’s cold in space, so why are the walls of various rockets only 50 mm thick?

tion and radiation. As counterintuitive as it might seem, in space, objects don’t lose heat via convection or conduction, because there isn’t any matter adjacent to them. Radiation on the other hand is a big deal, you’re either losing huge amounts to deep space, or gaining huge amounts of solar gain. Radiative heat loss or gain in terrestrial situations is mostly down to the net difference in radiation between two objects. Any object above absolute zero will emit some radiation, so if you have a cup of room temperature water next to a hot cup of tea, they both radiate heat to each other, but the hot one radiates more, so the net effect

74 | passivehouseplus.co.uk | issue 31

ised glass, this is mainly necessary to deal with re-entry. The Apollo modules just had boring old double glazing. There wasn’t even an exotic noble gas in the cavity, it was just left open to the atmosphere, or more to the point, the vacuum — because, well, those expensive gasses we use on earth are to reduce the convection and conduction, which we don’t have to worry about in a vacuum. Of course, people have tried vacuum glazing, and it sort of works, but the fused glass edges that help maintain the vacuum create a serious thermal bridge, and the little dots to stop the glass bending don’t look very pretty.

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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www.greenbuildingstore.co.uk ph+ | editor’s letter | 75


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76 | passivehouseplus.ie | Issue 21

Profile for Passive House Plus (Sustainable Building)

Passive House Plus (Sustainable building) issue 31 UK  

Issue 31 of Passive House Plus features the amazing Steep Wedge #passivehouse in Cork, and Agar Grove, by Hawkins Brown and Architype. Also...

Passive House Plus (Sustainable building) issue 31 UK  

Issue 31 of Passive House Plus features the amazing Steep Wedge #passivehouse in Cork, and Agar Grove, by Hawkins Brown and Architype. Also...

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