MODULE: Sustainable Refurbishment

H EAD I N G LY TE R RAC E S

R ETR O F I T

Design & Specification Report

Nicola Culliford 15th May 2024

Sustainable Refurbishment: Assignment2

MSc Architectural Technology & Design

C O NT ENTS

Appendix 1. Building Drawings (existing)

Appendix 2. Building Drawings (proposed)

HTR01 Ground Floor Plan

HTR02 First Floor Plan

HTR03 North Elevation

HTR04 South Elevation

HTR05 Gable Wall (East Elevation)

HTR06 Ground Floor: Ext. Wall Detail

HTR07 First Floor: Ext. Wall Detail

HTR08 Eaves: First Floor Ceiling Detail

Appendix 3. Fabric & Service Specifications

FS01 External & Party Walls

FS02 Ground Floor

FS03 Roof

FS04 Openings

FS05 Internal Partition Walls

FS06 First Floor

SS01 Space & Water Heating

SS02 Ventilation

SS03 Solar PV

1. Introduction and Context

1.1 Project Brief

The Headingly Terraces project addresses the retrofit design and specification of six adjoining residential properties in a suburb north of Leeds. The primary objective is to minimise environmental impact of the buildings through sustainable refurbishment.

Changes to internal layouts and building extensions are in scope of the project, where required as part of the retrofit design.

Constraints related to planning, building regulation and budget are lifted; however, design solutions and specifications should be practically and technically deliverable.

1.2 Existing Properties

The two storey, three-bedroom properties are of no-fines concrete construction, a cast in situ solid wall method first deployed in the UK during the 1940s.

No-fines walls are known to be structurally sound; however, density, air tightness and thermal performance can be inconsistent versus traditional methods.

Sub structure details are unconfirmed; however traditional concrete strip foundation below solidor doubleleaf (with concrete infill) masonry is likely (Fig. 2)

Timber boards on concrete slab and timber joists form the ground and first floors respectively and the pitched roof isof trussed rafter design with concrete tiles.

Heating is supplied viaindividual gas boilers and windows are double glazed UPVC.

Full provided fabric and service details can be found in Appendix 1. Building Drawings (existing).

Fig. 2. Sketch of typical no-fines foundation

Fig.1. Images of cut no-fines concrete wall

2. Retrofit Objectives

The project aims to minimise the environmental impact of the buildings and optimise sustainability through deep retrofit. On this basis the primary objectives of proposed design and specification are to: Minimise..

 Operational carbon generated from post retrofit use by reducing heat and energy demand, particularly from non-renewable sources

 Embodied carbon associated with upgraded properties by examining the impact of materials, services and methods specified for refurbishment and balancing this with the benefits delivered

 The impact of retrofit solutions on the wider environment Including water use, run off and biodiversity

3. RetrofitApproach

3.1 Standards for Performance

3.1.1 Building Operation

The established Passivhaus approach is adopted as the primary performance benchmark to steer design and specification. EnerPHit is the Passivhaus standard for retrofit of existing properties, demanding high levels of thermal performance, air tightness and indoor comfort to minimise energy and heat demand.

The table below outlines EnerPHit performance requirements in comparison to those for Passivhaus (for new buildings only) and latest UK Building Regulation (UK regs.).

ElementMeasurePassivhausEnerPHitUKRegs. ThermalPerformance-Opaquebuildingenvelope (extermalwalls,roof,groundfloor)U-Value0.15W/m2K0.15W/m2K0.18W/m2K* ThermalPerformance-Windows(wholewindow value)U-Value0.80W/m2K0.85W/m2K1.4W/m2K Ventilation-Heatrecoveryrate%75%75%73% SpaceHeatingDemandAnnualdemandperm215kWh/(m²a)25kWh/(m²a)N/A AirTightnessAirchangesperhr(ACH)0.6@50pa1.0@50pa10.0@50pa RenewableEnergyGeneration(EnerPHit+ standard)Annualgenerationperm260kkWh/m2/yr60kkWh/m2/yrN/A

*Groundfloorandexternalwallsonly,0.15W/m2Krequiredforroof PassivhausandEnerPHitmeasuresareprovidedfor'cooltemperature'climateasperUKconditions Passivhaus+andEnerPHit+measuresforextremeperformancearenotinlcuded,exceptforrenewableenergygeneration

Fig. 3. Comparison of Passivhaus, EnerPHit and UK Regs. Performance Standards

Retrofit solutions will be designed and specified to meet or exceed the EnerPHit standard where possible, with UK regs. applied as an absolute baseline target where the requirement is lower and EnerPHit standards are technically unachievable or would compromise overall environmental impact.

Passivhaus and EnerPHit allow compliance with either the standards for individual components or those for whole house energy demand; however, all projects are expected to deliver a reduction inpre retrofit energy demand of ≥ 75%.

The approach for this project will be to target component performance measures for the external building envelope (walls, floor, roof, windows) with impact on total heat and energy demand remaining an important consideration for design and specification.

Target performance measures and approaches to retrofit specification for building fabric and service elements are documented in Appendix 3. Fabric & Service Specifications.

3.1.2 Retrofit Solutions

Environmental impact and embodied carbon of the project and post retrofit buildings will be considered in design and specification, using the Life CycleAssessment approach.

With budget being removed as a constraint, solutions will be considered based on a balance between contribution to operational performance and whole-life sustainability.

The image below provides an example Life Cycle Assessment (LCA) approach to support decision making when assessing retrofit solutions.

Fig. 4. Example LCA Approach and Considerations

3.2 Passive Design

Aligned with Passivhaus principles, optimising passive design opportunities is key to project design.

Maximising the thermal efficiency and air tightness of the properties through high performing insulation, a continual air tight layer and solar gain will minimise the demand for heating and cooling.

Optimising what can be achieved through consideration of the properties’ location, orientation, form and layout isan important part of the design process.

3.3 Resident Experience

Current property occupants are working families; however, specific details of circumstances and operational preferences and behaviours are not known.

Early engagement with residents of properties undergoing retrofit works has been identified as fundamental to the successful outcomes, particularly when considering post completion use of services. The ‘Social Housing Retrofit Alliance’ offers support to refurbishment projects funded by the government’s Social Housing Decarbonisation Fund (SHDF) and advocates timely and appropriate communication with residents to optimise the outcomes of retrofit and support the use of new and often unfamiliar services such as mechanical ventilation.

The scale of proposed works will necessitate displacement of residents during early phases of retrofit; therefore, a detailed resident engagement and communication plan is recommended to minimise impact and support a positive relationship between occupants and contractors.

3.4 Forecasting and Measuring Impact

3.4.1

Establishing a Baseline

Linear thermal bridging data has been provided from pre retrofit testing; however, no other data is available to determine fabric or operational performance of the existing properties.

It is recommended that pre retrofit testing is undertaken to validate the thermal performance and air tightness of retained elements including floor slab, roof and external walls to provide a baseline for improvement and identify any areas of concern.

Gathering available data on existing energy and heat demand will be essential to assess the reduction in demand post retrofit (target = ≥75% as per EnerPHit standards).

3.4.2 Forecasting Performance

The Passivhaus Planning Package (PHPP) is recommended as a method for accurately forecasting post retrofit performance, as well as informing specifications through calculation of optimum requirements for elements such as glazing ratios, fabric performance and heating/cooling demand.

The following approaches have been adopted for early estimation of post retrofit performance, prior to PHPP modelling, and to inform the solutions outlined in Appendix 3. Fabric & Service Specifications:

Thermal performance of fabric elements

U-Values are calculated from K and/or R values provided via manufacturer technical data for proprietary products and/or representative products where a number of solutions are available.

For generic elements, standard K and/or R values are taken from documented insight (e.g. The Architect’s Pocket Book).

Service Performance

Technical manufacturer’s data is used to inform forecast performance for retrofit service elements including heating, hot water and ventilation. Where a proprietary solution is not identified, data is taken from a standard representative example.

NB. For both fabric and service performance, forecast performance should be verified with solution providers based on final specific design and specification outlined for this project.

Total Energy Demand

Where available, data on existing energy use should be recorded as a baseline to inform total reduction achievement post retrofit.

Solutions specified for fabric and service upgrades are presumed to have a significant impact on total heat and energy demand; however, this can be more accurately modelled via use of PHPPsoftware.

AirTightness

The target level for air tightness (EnerPHit standard 1.0@50pa) is presumed as the forecast performance measure.

Aprogramme of periodic testing (via ‘blower door’ method) will be carried out to assess air tightness levels versus target and identify sources of air leakage to address prior to completion.

3.4.3 Measuring Results

It is important to consider both qualitative and quantitative data in the evaluation of post retrofit performance.

QuantitativeAssessment

The use of PHPP software is proven to generate a highly accurate model of post occupancy performance and this can be enhanced with actual measurement of energy demand from meter data after an appropriate period of ‘as built’operation.

To avoid the issue of ‘performance gap’ where forecast measures exceed those achieved in reality, a more intensive programme of post-occupancy evaluation is recommended, including in-situ testing of:

 Indoor air temperature

 Indoor surface temperature

 Relative humidity

 Ventilation flow rate

Testing a sample of two properties (to include end and middle terraces) will reduce required resources, effort and resident disruption.

QualitativeAssessment

The experience of occupants and their perception of retrofit improvements can have a significant impact on the effective operation of building services. How comfortable the properties feel to residents is an important measure of success alongside measured performance data.

As part of the resident engagement and communication plan recommended as an early project output (see 3.3 Considering Resident Experience and Impact), a schedule of resident post occupancy evaluation will be prepared to capture qualitative data for at least twelve months after completion of works.

Any insight from qualitative assessment that identifies risk to the effective use and performance of upgraded building services (e.g. switching off MVHR, leaving windows open) will be addressed with urgency to optimise actual operational performance of the retrofit properties.

4. Retrofit Proposal

4.1 Constraint & Opportunities

The following images communicate key constraints presented by the existing properties and the opportunities to address these to meet the project objective of minimising environmental impact:

4.1.1 Constraints

4.2 Design

Details of the proposed retrofit design are captured via plan, elevation and detail drawings in Appendix 2. Building Drawings (proposed).

The key design features delivered are:

Form

 Removal of the protruding external store and porch (north) to optimise building form factor and reduce external insulation requirement

 Roof rafters are extended to retain overhang beyond new external wall faces

 External window reveal depths optimised to contribute to shading

Layout

 Kitchen and living areas are rotated to optimise solar gainto habitable space

 Glazed internal double doors installed between new kitchen and living space to optimise natural light

 Smallentry/utility created at new rear entry to mitigate loss of porch

 Room dimensions and storage space retained

 W.C moved from front (north) to rear entry (south)

 Airing cupboard & Bed. 3 store re sized to accommodate MVHR and hot water units (first floor) re sized

Fabric

 External wall insulation (EWI) installed to all elevations, extending to base foundation

 Triple glazed windows and insulated panel doors installed

 Living room window enlarged and side light installed (south) to optimise solar gain

 Insulating screed applied as air tight layer to existing ground floor slab

 First floor structure replaced with lightweightposi joists with service void

 Cold loft design installed to roof, with insulation added above ceiling joists

 Internal wall faces parge coated to protect no-fines substrate andcreate airtight layer

 Ground, wall and first floor ceiling air tight layers overlapped at perimeter junctions

 Mineral wool specified as low carbon, recyclable EWI and cold loft insulation

 Existing concrete rooftiles retained and reused

 Redundant timber (joists, studs) repurposed for external store construction

Services

 Infra-red heating specified as high efficiency, low maintenance system

 On-demand hot water system negates requirement for hot water tank

 MVHR provides controlled ventilation and heat recovery

 Solar PV installed (second phase) to introduce renewable energy

Additional Design Factors

 Landscaping is not in projects scope; however permeable materials for hard surfacing are recommended to reduce water run off

 Low flow WCs are installed and along with an over bath shower to the first-floor bathroom, to reduce water use

 Significant construction and associated works/materials are avoided (e.g. replacement floor slab, extension of existing porch) to reduce embodied carbon

4.3 Specification

Specification of individualbuilding and fabric service elements are detailed in Appendix 3. Fabric & Service Specifications

Specifications include the following detail:

Fabric Specifications

Existing construction

Target Performance measures

Approach to retrofit design

Specification for individual components

Service Specifications

Existing provision

Target performance measures

Approach to retrofit design

Specification for individual components

4.4 Strategies

Heating

100%+ Infra-red independently controlled heating panels, ceiling mounted to optimise usable floor space

Compact on-demand hot water system with battery for off-peak charging

AirTightness

Screed coat to floor slab and internal no-fines walls and membrane to underside of first floor ceiling joists – overlapped at perimeter junctions

Penetrations for fixings and service outlets sealed with appropriate tapes and grommets

Wall studs and floor joist taped to air tight parge coat at wall abutment

Thermal Bridging

Insulation applied to internal window returns

Replacement windows and doors installed within EWI layer

Proprietary ‘in front of wall’framing system window installation

Ventilation

90%+ heat recovery rate mechanical ventilation system with automatic bypass

Parging recommended for periods of extreme heat

Renewables

Solar PV installation (with storage battery) planned for phase two retrofit

Heating and hot water systems solar PV ready

See Appendix 3. Fabric & Service Specifications for detailed information

Image References

Fig. 1

Fig. 2

Fig. 3

Fig. 4

Non-Standard Housing Forum, https://nonstandardhouse.com/whatexactly-is-no-fines-concrete-why-use-it-to-build-houses/

The Structural Condition of No-Fines Concrete Low-Rise Dwellings, Reeves and Martin, 1989, p. 1

N. Culliford, created 14th May 2024

Life-Cycle Assessment and the Environmental Impact of a Building, Epsten Group, n.d, https://epstengroup.com/building-life-cycleassessment/

Appendix 1. Building Drawings (Existing)

Site:HeadingleyLeeds Semi-Urban NotSheltered Noplanningrestrictions

Age:1960's

Form:Terraceof5dwelling,offset betweenNo.16and17.

2storeys,groundfloorand firstfloor.coldloftspace

Externalwalls:No-finesconcrete, finishedwithrenderandpebble dashexternallyandplasterboardon timberstudsinternally.

Internalwalls:Timberstudfinished withplasterboard.

Groundfloor:Concretesolidfloor

Intermediatefloor:Timberfloor boardsontimberjoists,running paralleltofrontofbuilding.

Roof:Concretetileroof,supported ontrussedrafters.mineralwool insulationlaidbetweenrafters, 100mmdepth.

Windows:UPVC,doubleglazed Services: Heating:Oldgasboiler(efficiency< 50%)Supplieswaterradiators.

Hotwater:Hotwatertanksupplied byboiler,withelectricalimmersion heater.

Ventilation:Trickleventsin windows.

Occupancy:Workingfamilies

Operations:Heatingcontrolledby thermostat,setto21°C

PsiValues(W/m-K)

Roof-Wall0.180

Wall-Groundfloor0.240

Wall-Wall(corner)0.140

Wall-1stfloor0.110

door/windowlintel0.450

Windowsill0.080

Window/doorjamb0.090

15-20NotionWay,Headingley Leeds

Scale:1:100&1:200@A3

Appendix 2. Budling Drawings (Proposed)

South Elevation: Proposed

Floor

Ra ers extended to retain overhang beyond EWI

Concrete les retained and re-laid above breathable VPM

Future phase solar PV installa on

208mm depth added to external walls through EWI installa on

Textured, weatherproof render finish to EWI

MVHR inlet and outlet valves (indica ve loca ons)

Living Room window enlarged and side light installed to main entry Triple glazed windows installed (openings retained to first floor)

PROJECT: HeadinglyTerraces Retrofit / DRAWING REF: HTR04 / DRAWN BY: N Culliford

DATE: 15th May 2024

SCALE: 1:150 @A1

EWI extended to founda on base

Internal blinds provide controlled shading

F.

Ground Floor Plan: Proposed

External store and entry porch removed and flush entry/u lity created

Living space relocated to south eleva on, kitchen/diner to north

Con nuous EWI layer to external walls

Glazed doors to transfer daylight to kitchen

Internal window reveals insulated & internal/external EWI corners sealed to reduce thermal bridging

KEY: LR window enlarged & side light introduced to main entrance

PROJECT: HeadinglyTerraces Retrofit / DRAWING REF: HTR01 / DRAWN BY: N Culliford

DATE: 15th May 2024

SCALE: 1:100 @A1

Replacement triple glazed windows fixed within insula on layer of external walls North

Single side insula on to party wall

Indicative infra-red heating panel output and location to be informed by installer

Indicative MVHR supply & extraction vents ducting routes to be informed by system provider

First Floor Plan: Proposed

Con nuous EWI layer to external walls

North

Over bath shower & low

flow W.C installed

MVHR & on demand HW

units installed to exis ng airing cupboard (MVHR close to external wall to minimise duct runs)

Bedroom dimensions and storage spaces retained

Internal window reveals insulated & internal/external EWI corners sealed to reduce thermal bridging

PROJECT: HeadinglyTerraces Retrofit / DRAWING REF: HTR02 / DRAWN BY: N Culliford

DATE: 15th May 2024

SCALE: 1:100 @A1

Single side insula on to party wall

Replacement triple glazed windows fixed within insula on layer of external walls

KEY:

Indicative infra-red heating panel output and location to be informed by installer

Indicative MVHR supply & extraction vents ducting routes to be informed by system provider

North Elevation: Proposed

Ra ers extended to retain overhang beyond EWI

Concrete les retained and re-laid above breathable VPM

208mm depth added to external walls through EWI installa on

Floor

Textured, weatherproof render finish to EWI

Kitchen window reduced in size and wall panel infilled

External store and entry porch removed and flush entry created

Triple glazed windows installed (openings retained to first floor)

PROJECT: HeadinglyTerraces Retrofit / DRAWING REF: HTR03 / DRAWN BY: N Culliford

DATE: 15th May 2024

SCALE: 1:150 @A1

EWI extended to founda on base

F.

Gable Wall (East Elevation): Proposed

Future phase solar PV installa on

Raters extended to retain overhang beyond EWI

Textured, weatherproof render finish to EWI

Concrete les retained and re-laid above breathable VPM

208mm depth added to external walls through EWI installa on

External store and entry porch removed and replaced with flush entrance

PROJECT: HeadinglyTerraces Retrofit / DRAWING REF: HTR05 / DRAWN BY: N Culliford

DATE: 15th May 2024

SCALE: 1:100 @A1

Moisture resistant EWI below DPC level, extending to base founda on

Ground_External Wall Detail: Proposed

Structherm structural EWI with 200mm mineral wool core

Textured, weatherproof render finish

12.5mm lightweight breathable plasterboard alterna ve & 3mm breathable plaster skim coat

FSC/PEFC approved mber studs fixed to internal wall and taped at abutments

6mm parge coat applied to internal solid wall (forms air ght layer)

Thermabase ‘below DPC’ EWI system extended to base founda on

40mm Insula ng floor screed overlapped with internal wall parge coat at perimeter

Retained concrete floor slab

Presumed exis ng DPM

Presumed sub structure: double leaf masonry founda on wall on concrete strip foo ng

PROJECT: HeadinglyTerraces Retrofit / DRAWING REF: HTR06 / DRAWN BY: N Culliford

DATE: 15th May 2024

SCALE: N/A Not toScale

Structherm structural EWI with 200mm mineral wool core

Textured, weatherproof render finish

FSC/PEFC approved mber studs fixed to internal wall and taped at abutments

6mm parge coat applied to internal solid wall (forms air ght layer)

Therma Blok® Thermaslim ultra fine internal floor insula on system @13mm

Cork/carpet floor finish

No-fines solid wall

203mm posi joists (taped at wall abutment)

Party wall adopts internal wall detail with addi on of 37mm insula ng plasterboard to single side

3mm breathable plaster screed coat over 12.5mm breathable plasterboard alterna ve

PROJECT: HeadinglyTerraces Retrofit / DRAWING REF: HTR07 / DRAWN BY: N Culliford

DATE: 15th May 2024

SCALE: N/A Not toScale

Eaves_First Floor Ceiling:Proposed

Exis ng concrete les re-laid over breathable, vapour permeable membrane

Mineral wool insula on extended into eaves to meet EWI

Lo Zone flooring system fixed to ceiling joists to raise floor above insula on.

EcoBoard flooring panels

Exis ng 100mm mineral wool insula on re-laid between truss ceiling joists, with addi onal 150mm laid above joists @ 90 degrees

Ra ers extended beyond EWI layer

Structherm structural EWI with 200mm mineral wool core

Textured, weatherproof render finish

No-fines solid wall

3mm breathable plaster skim coat over 12.5mm breathable plasterboard alterna ve

ProClima Solitex Plus intelligent vapour control membrane (taped to internal wall parge coat to form air ght layer)

PROJECT: HeadinglyTerraces Retrofit / DRAWING REF: HTR08 / DRAWN BY: N Culliford

DATE: 15th May 2024

SCALE: N/A Not toScale

Appendix 3. Fabric& Service Specifications

Building Element

Existing Construction

External & Party Walls

External: Solid ‘no-fines’concrete with pebbledash render finish

Internal: Plasterboard on timber studs (internal & party walls)

Total Wall Depth (external render to internal plaster): 280mm

Estimated U-Value: 1.23 W/m2K (1)

Thermal performance, air leakage, density and composition likely to be inconsistent across individual walls and properties (2) (3)

Proposed Construction

Corresponding Drawings

Performance Requirements

HTR05 Ground Floor: External Wall Detail

Maximum U-Value (UK Building Regs.) = 0.18 W/m2.K

Target U-Value (EnerPHit) (5) = 0.15 W/m2.K

RetrofitApproach

EXTERNAL WALL INSULATION (EWI):

Application of retrofit works to the entire terrace block, along with absence of building conservation constraints, allows specification of an externalwall insulation (EWI) system to:

 Optimise thermal performance of the building envelope

 Minimise reduction of internal space

 Maximise weather protection

 Contribute to airtightness levels

Proprietary ‘structural’EWI system Structherm is identified as a preferred solution based on local manufacture (within 30 miles from site) and suitability for non-traditional wall construction including nofines concrete, whereconsistency of substrate andsubsequent wind-loadand pull-outstrength cannotbe guaranteed. Steel cage supported insulation panels and a 30% reduction in fixing points (versus standard EWI) minimise disturbance to existing solid wall construction.

Mineral wool is selected for the caged insulation layer as a renewable, recyclable product with high thermal performance.

Compatible below damp-proof course (DPC) level EWI layer Thermabase is installed down to base foundation level, to mitigate thermal bridge risk via retained floor slab (see ‘Fabric Specification 02 –Ground Floor’).

In-situ testing of external wall construction thermal performance is recommended (pre retrofit), to accurately specify insulation depth for maximum required U Value. (4)

INTERNAL LINING

Existing timber studs and plasterboard to ground and first floors are stripped, due to likely deterioration; however,wheretimberconditionis sound,effortsshouldbemade tore-purpose (e.g.external store construction).

Removalofexistingfirstfloorjoistsandfirstfloorceiling(see Fabric Specification 06 – First Floor)provides clear access to apply a gypsum based parge coat direct to wall from ground floor to underside of loft.

Parge coat applied to exposed no-fines substrate provides moisture protection, repair to surface defects and forms vertical component of the internal air tight layer.

Areplacement stud and plasterboard system are installed to ground and first floors following completion of newfirstfloor structure,ground floorupgradeand first floorceilinginstallation. Penetrationstothe air tight layer through stud fixing are addressed via suitable taping and seals (see Air Tightness Strategy).

Existing plasterboardsare replaced withabreathable,lightweightalternative toenhance thermal and acoustic insulation and minimise moisture risk within service voids.

Existing plasterboard is appropriately disposed of via local council or national supplier recycling schemes, to reduce environmental impact of works.

PARTY WALLS

EWI installation protects party walls from external heat transfer

Treatment mirrors that for internal lining of exterior walls (above)

Riskofthermaltransfer(duringperiodsofnon-occupancyorineffectiveheatinguse)andacoustictransfer between properties is mitigated through replacement of standard plasterboard with insulating plasterboard to single face of party walls (to minimise impact on internal floor space).

In-situ testing of party wall thermal and acoustic transfer is recommended (pre retrofit), to validate lining specification.

EXTERNALWALLINFILL

Infill method for cut voids to existing no-fines concrete walls to accommodate:

 Removal of protruding store/entry hall and replacement with flush rear entry to north elevation

N Culliford / Headingly Terraces Retrofit/ May 2024 – Appendix 1: Fabric & Service Specifica ons

 Reduction in kitchen window dimensions to rear/north elevation

 Reduction in opening for entry door and halfheight side light

..tobeagreedwithstructuralengineer.SpecifiedsolutionmustmaintainappropriatesubstrateforEWIand internal wall linings (including air tight parge coat layer).

Fabric & ComponentSpecification

External Wall Insulation (EWI)

Structherm structural system (SEWI) (6) eaves to DPC level comprising of:

- 200mmmineral wool insulation (depth to be confirmed following pre retrofit testing), within…

- Steel caging, secured to no-fines substrate with bespoke fixings

- 6mm render basecoat

- 1.5mmweatherproof, breathable silicone finishing render coat (shade and texture to suit resident preference and local architectural aesthetic)

Structherm Thermabase (7) moisture resistant insulation panel adhered to substrate down to base foundation level

Internal Parge Coat

Gypsum based non permeable plaster (e.g. British Gypsum Gyproc Soundcoat Plus) (8)

applied direct to internal wall face @ 6mm depth

Internal Wall Lining: External Wall

Internal Wall Lining: Party Wall

12.5mm lightweight, breathable board (e.g. Adaptavate BreathAboard low carbon plasterboard alternative) (9) fixed to…

63mm x 38mm (FSC/PEFC approved) timber studs @600mm centres, finished with…

2-3mm plaster skim coat (e.g. Adaptavate BreathAplasta) (10)

Ultra-thin insulated plasterboard (e.g. Kingspan Kooltherm K118 @ 37.5mm) (11) fixed to,

63mm x 38mm (FSC/PEFC approved) timber studs @600mm centres, finished with…

2-3mm plaster skim coat (e.g. Adaptavate BreathAplasta) (12)

N Culliford / Headingly Terraces Retrofit/ May 2024 – Appendix 1: Fabric & Service Specifica ons

References

(1) ‘No-fines concrete in the UK social housing stock: 50 years on’, Sommerville et. al, Structural Survey Vol. 29 No. 4, 2011 p. 295

(2) ‘Measuring and modelling retrofit fabric performance in solid wall conjoined dwellings’., Parker et. al, Published in ‘Energy & Buildings 185 (2019)’ p.52

(3) ‘Wimpey No Fines’,Non Standard House Construction Forum, 2019, https://nonstandardhouse.com/wimpey-no-fines-in-situ-concrete-house/

(4) Measuring and modelling retrofit fabric performance in solid wall conjoined dwellings’., Parker et. al, Published in ‘Energy & Buildings 185 (2019)’ p.64

(5) EnerPHit ‘Criteria for Buildings’(version 10c), Passivhaus Institute, 2023, pp. 10-14

(6) Structherm SEWI Product Brochure, Structherm, 2023, https://www.structherm.co.uk/wpcontent/uploads/2022/09/StructhermSystemsBrochure2022.pdf

(7) Structherm SEWI Product Brochure, Structherm, 2023, https://www.structherm.co.uk/project/thermabase/?et_fb=1&PageSpeed=off

(8) Gyproc Soundcoat Plus - Product Information, British Gypsum, 2022, https://www.britishgypsum.com/products/finishing-products/gyproc-soundcoat-plus

(9) Kingspan Kooltherm 118: Insulated Plasterboard – Product Information, Kingspan, 2023, https://www.kingspan.com/gb/en/products/insulation-boards/wall-insulation-boards/kooltherm-k118insulated-plasterboard/

(10) Breathaboard – Product Information,Adaptavate, 2024, https://adaptavate.com/products/breathaboard

(11) (12) Breathaplasta – ProductInformation,Adaptavate, 2024, https://adaptavate.com/products/breathaplasta

N Culliford / Headingly Terraces Retrofit/ May 2024 – Appendix 1: Fabric & Service Specifica ons

Building Element Ground Floor

Solid concrete slab above presumed strip foundation construction, with masonry substrate to DPC level (1)

Presumed damp proof membrane laid under slab (2)

Existing Construction

Corresponding Drawings

Performance Requirements

No confirmed insulation to floor slab or perimeter

Floor covering type and depth unconfirmed

Estimated Depth: 100-125mm (slab), 38-40mm (screed)

Estimated U-Value:1.4 W/m2K

Proposed Construction

HTR06 – Ground Floor: External Wall Detail

Maximum U-Value (UK Building Regs.) = 0.18 W/m2.K

Target U-Value (EnerPHit) (5) ≤ 0.15 W/m2.K

RetrofitApproach

Options for insulating the existing floor slab, without impacting existing ceiling height (2.4m) and external door thresholds, are limited.

Excavation and replacement of the existing slab to accommodate below slab insulation is not recommended due to subsequent increased building works, material use and associated environmental impact.

Inconjunctionwiththeextensionofexternalwallinsulation(EWI)tofoundationbase(3) (see Specification FS01 – External & Party Walls), the existing slab is retained with presumed 30-40mm screed layer removed (4) and replaced with a high-performing insulating screed over proprietary ultra-thin insulation panels, as substrate for finished floor covering. Cork is specified as the preferred covering to optimise whole floor U-Value.

EWIextended tofoundationbasemitigatesthe requirementfor aperimeterinsulationupstand,allowing overlap of floor screed with internal wall parge coat to provide continuity of the air tight layer.

Forecast U-Value: 0.15 W/m2.K

Estimated increase in floor depth: 22-34mm

Concrete Floor Slab

Fabric & ComponentSpecification

Existing slab (with presumed DPM to underside) retained

Presumed R-Value** (@ 100mm thickness): 0.007 m² K/W

Kingspan Optim-R® @20mmthickness

Above Slab Insulation

Calculated R-Value*: 2.86 m² K/W

High performing insulating screed (e.g ProofShield Thermscreed™ @ 40mm thickness).

Application to overlap parge coat at wall perimeter for continuity of air tight layer.

Screed Layer

Floor Covering

Additional application of air tight tape to seal wall: floor junctions may be required, subject to results of interimairtightness tests.

Calculated R-Value*: 0.4 m² K/W

Cork floor covering @approximately 12mm(including underlay)

Calculated R-Value*: 3.6 m² K/W (min.)

**Presumed R Value based on standard K Value data for common building materials (5) **Calculated R Value based on technical data (K Values) provided by manufacturers for proprietary or representative components

References

(1)TheStructuralConditionofNo-FinesConcreteLow-RiseDwellings,ReevesandMartin,1989,sec.2.3 (2)Practicalimplementationsofstepby-step-retrofittoEnerPHitstandard,PassivhausInstitut,2022, Sec. 3.2 Envelope, https://passipedia.org//planning/refurbishment_with_passive_house_components/practical_ implementations_of_step_by_step_retrofit_to_enerphit_standard (3) (4) EvolutionofBuilding Elements, Groundbearingconcrete floors- 1960sto 1990s, University ofthe West of England, 2009, https://fet.uwe.ac.uk/conweb/house_ages/elements/section3.htm (5)Architect’s Pocket Book, Hetreed et. al, 2017, p. 178

Building Element Roof

Trussed rafter construction with concrete tile covering

Existing Construction

Corresponding Drawings

Performance Requirements

Drawings indicate 150mm depth (presumed to include rafter, batten, tile)

Slope = 28 degrees

Proposed Construction

HTR08 Eaves: First Floor Ceiling Detail

Maximum U-Value (UK Building Regs.) = 0.15 W/m2.K

Target U-Value (EnerPHit) ≤ 0.15 W/m2.K

RetrofitApproach

The existing trussed rafter structure limits useable roof space and access; therefore, a cold loft design is specified to minimise total volume of internal space within the insulation and air tight layers of the properties.

Locating MVHR unit in first floor storage space further negates requirement for an insulated loft area.

The existing roof covering is stripped to allow:

 Extension of rafters to accommodate increased wall depth created by external wall insulation

 Installation of a breathable, vapour permeable membrane above the rafters

 Cleaningandre-useofexistingconcretetilesandtimberbattens(subjecttocondition),making a significant contribution to minimising embodied carbon.

Subject to condition, the existing mineral wool (100mm) laid between rafters is e re purposed to lay between truss ceiling joists, with loft floor raised to accommodate additional insulation above joists.

Use of a proprietary flooring system mitigates compression risk to new, deep insulation layer.

Continuity of the air tight layer is achieved through installation of an intelligent vapour control air tight membrane below ceiling joists, taped at abutment with parge coated internal walls.

Penetrations to the air tight layer to accommodate lighting, heating and ventilation fixtures are addressed via appropriate sealing products and solutions (see Air Tightness Strategy

Solar PV panels are specified for installation to the front/south elevation roof slope; however, it is recommended that these are specified and installed in a second works phase to enable accurate

specification based on measured energy demand following primary retrofit works (see Service Specification 04 – Solar PV).

Forecast U-Value: 0.15

Roof Covering

Fabric & ComponentSpecification

Re-use of existing concrete tiles (subject to condition)

R Value: N/Anot included in roof U-Value

Loftzone Anti-Compression Flooring System inc. 18mm Eco loft boards (1)

Floor Covering

Insulation

Air TightLayer

R Value: 0.12

Existing 100mm mineral wool insulation retained between ceiling joists

Additional 150mmmineral wool insulation laid above joists @ 90 degrees

R Value: 6.25

Intelligent vapour control air tight membrane (e.g. ProClima Solitex Plus) (2)

Laid below joists and taped to internal wall parge coat

R Value: N/A

Ceiling

Substrate

Ceiling Finish

12.5mm lightweight, breathable board (e.g. Adaptavate BreathAboard low carbon plasterboard alternative) (3) fixed direct to joists

R Value: 0.16

2-3mm plaster skim coat (e.g. Adaptavate BreathAplasta) (4)

R Value: 0.025

References

(1) StoreFloor – Product Information, Loftzone, 2024, https://www.loftzone.co.uk/loft-storefloor/ (2) Pro Clima Solitex Plus Breathable VPM– Product Information, Greenspec.co.uk, https://www.greenspec.co.uk/green-products/wind-tightness-membranes/details/pro-clima-solitex-plus/ (3) Breathaboard – Product Information,Adaptavate, 2024, https://adaptavate.com/products/breathaboard (4) Breathaplasta – Product Information,Adaptavate, 2024, https://adaptavate.com/products/breathaplasta

Building Element External Openings

Existing Construction

Corresponding Drawings

(Windows) UPVC double glazed units, flush with internal wall (Doors) Unconfirmed, presumed timber or UPVC double glazed

Estimated whole window U Value: ≥ 2.0 W/m2.K

Proposed Construction

HTR01 Ground Floor Plan, HTR02 First Floor Plan, HTR02 North Elevation, HTR03 South Elevation

Maximum whole window U-Value (UKBuilding Regs.) = 1.4 W/m2.K

Performance Requirements

Target whole window* U-Value (EnerPHit)≤ 0.85 W/m2.K

Target Psi for linear junctions (Passivhaus)** ≤ 0.01

*Applies to windows only, no stated criteria for doors **No stated standard for EnerPHit

RetrofitApproach

To maximise thermal performance and durability of the external building envelope…

All windows are replaced with Passivhaus approved timber frame, low-e triple glazedunits, and front (south)andrear(north)entrydoorsarereplacedwithanequivalentpre-insulatedtimberpanelalternative.

Aluminium clad timber is specified for window frames and door panels, to increase weather resistance and reduce maintenance requirement.

Windows and doors are fitted within the insulated layer of retrofitted external wall structure, with an ‘in front of wall’installation system recommended to reduce thermal bridging.

Outwardopeningspecifiedforallwindowsanddoorstooptimisewindresistanceandminimiseimpact on internal spaces.

To exploit solar gain and maximise daylight…

Window frame widths are reduced versus existing windowdesign.

The existing ground floor window is enlarged and a half-height side light is introduced to the entry door (south elevation).

Window and door design accommodates maximum practical reveal depths (external) and Passivhaus recommended glazing:floor space ratios (1)to mitigate overheating risk.

Internal blinds are recommended for additional, resident operated shading.

Fabric & ComponentSpecification

Passivhaus approved low-e triple glazed units with aluminium clad timber frame (e.g. Norrsken Alu-Clad 300 Series) (2)

Windows

External Entry Doors

Individual U-Values for glazing and frame, spacer Psi value and whole window UValue to be verified by chosen manufacturer

Forecast U-Value (whole window): 0.75 – 0.8 W/m2.K

Passivhaus approved insulated panel unit with aluminium clad timber frame (e.g. Norrsken Alu-Clad 300 Series) (3)

Product U-Value to beverified by chosen manufacturer

Forecast U-Value: 0.75 – 0.8 W/m2.K

Installation System

Insulating, load bearing ‘in front of wall’system to house window and door frames within insulated layer of external wall (e.g. ISO-TOP Winframer) (4)

Forecast U-Value: 0.20 – 0.50 W/m2.K

References

(1) How to Build a Passivhaus – Good Practice Guide, PassivhausTrust, 2023, p. 47

(2) 300 Series – Outward OpeningAlu-Clad Window, Norrsken, 2024, https://www.norrsken.co.uk/product/door/S307A

(3) 300 Series – Outward OpeningAlu-Clad Door, Norrsken, 2024, https://www.norrsken.co.uk/product/door/S307A

(4) In Front of Wall Installation System - ISO-TOPWinframerType 1, Iso Chemie, 2024, https://www.isochemie.eu/en-GB/sealing-solutions/sealing-products/in-front-of-wall-installation-systems/iso-topwinframer-type-1

Building Element First Floor

Timber floorboards ontimber joists

Joists run parallel to front/south elevation

Existing Construction

Corresponding Drawings

Performance Requirements

RetrofitApproach

Connection of joists to solid walls presumed via ‘cast in’fixings and wall plate (1)

Presumed first floor depth (inc. ceiling) is 246mm (2)

Proposed Construction

HTR07 First Floor Detail

Minimum insulation layer R Value (UKBuilding Regs) ≥ 0.5(m2·K)/W

Theexistingfloorisremovedandreplacedwithlighterweight‘posi’joiststoreducestructuralloadon solid wallsandprovideservice voidfor MVHRducting. Wheretimber conditionis sound, effortsshould be made to re-purpose existing joists (e.g. external store construction).

Absence of hot water cylinder (see Specification SS01 – Space & Water Heating) reduces first floor load and allows specification of replacement posi joists to retain existing joist depth.

Strippingofexistingjoists allowsapplicationof aconsistentairtight parge coat tointernal walls (see Specification FS01 – External & Party Walls).

Ground and First floor ceiling heights are retained through specification of a proprietary ultra fine insulated flooring system above joists.

Penetrations to the air tight layer through fixing of new floor construction are addressed via suitable taping and seals (see Air Tightness Strategy).

Fabric & ComponentSpecification

10-12mm natural, durable covering (e.g. cork or sustainable carpet) to be selected in accordance with resident preference

Floor Covering

Floor Substrate

Structural Joists

Ceiling Substrate

Ceiling Finish

Thermablokl® Aerogel Thermaslim ultra fine internal floor insulation system (3) @13mm

Calculated R Value ofinsulation element*: 0.6 (m2·K)

203mmtimber ‘posi’joists @ 600mmcentres (to be validated by structural engineer)

12.5mm lightweight, breathable board (e.g. Adaptavate BreathAboard low carbon plasterboard alternative) (4) fixed direct to joists

2-3mm plaster skim coat (e.g. Adaptavate BreathAplasta) (5)

*Calculated R Value based on technical data (K Values) provided by manufacturers for proprietary or representative components

References

(1)The Structural Condition of No-Fines Concrete Low-Rise Dwellings, Reeves and Martin, 1989, fig. 1 (2)The Structural Condition of No-Fines Concrete Low-Rise Dwellings, Reeves and Martin, 1989, fig. 2 (3)AerogelThermal Internal Floor Insulation System – Product Information, Thermablock. 2023, https://www.thermablok.co.uk/our-products/thermablok-aerogel-magnesium-floor-board/ (4) Breathaboard – Product Information,Adaptavate, 2024, https://adaptavate.com/products/breathaboard (5) Breathaplasta – Product Information,Adaptavate, 2024, https://adaptavate.com/products/breathaplasta

Building Element Internal Partition Walls

Plasterboardon timber stud

Existing Construction

Approx. 100mm depth (indicated by drawings) Proposed Construction Corresponding

RetrofitApproach

Internal partition walls are removed to facilitate works to ground, first and loft floors.

Subject to dimensions and condition, existing timber studs may be reusable for new partition walls, otherwise efforts should be made to repurpose (e.g. construction of external store, noggins etc.).

New insulated partition walls are installed to accommodate revisions to existing floorplan, provide service void for electrical cabling and minimise heat loss between internal spaces.

Existing plasterboard is appropriately disposed of via local council or national supplier recycling schemes, to reduce environmental impact of works.

Fabric & ComponentSpecification

FSC/PEFCapproved timber studs @600m centres

Studs

Dimension 63mm x 38mm to minimise reduction in overall floor space

Substrate 12.5mm lightweight, breathable board (e.g. Adaptavate BreathAboard low carbon plasterboard alternative) (1) fixed direct to joists

Finish 2-3mm plaster skim coat (e.g. Adaptavate BreathAplasta) (2)

References

(1) Breathaboard –Product Information,Adaptavate, 2024, https://adaptavate.com/products/breathaboard (2) Breathaplasta –Product Information,Adaptavate, 2024, https://adaptavate.com/products/breathaplasta

Building Element Space & Water Heating

Existing Provision

Gas boiler supplies wet central heating system (radiators) and hot water tank with immersion (≤ 50% efficiency) Proposed Provision

Corresponding Drawings

Performance Requirements

HTR01 Ground Floor Plan, HTR02 First Floor Plan

Minimum Output Efficiency (UK Building Regs) ≥ 100% (1)

Heating Control (UKBuilding Regs): Room based operation and thermostatic control (2)

RetrofitApproach

The existing gas boiler is removed and replaced with independent supply solutions:

Space Heating

Electric powered infra-red heating panels at ceiling level replace existing radiators, negating requirement for wet system service pipes and associatedmaintenance.

≥ 100% panel efficiency, ‘radiation’heat method and independently operating units enable rapid, controlled space heating.

Embodied carbon is reduced through reduced materials, installation and maintenance associated with IR systems (versus alternatives such asASHP).

Solar PV installation during phase tworetrofit reduces space and water heating demand on mains energy (see Service Specification SS03 - Solar PV).

Hot Water

Aproprietary tankless ‘on demand’hot water system replaces the existing hot water tank, reducing space requirements.

Integrated battery enables off-peak charging and future connection to solar PV

Lightweight, compact form enables wall mounting and reduced installation/maintenance effort.

Component Specification

Infra-Red Panels

High efficiency (110% +) infra-red panel system (e.g. Herschel ‘Comfort’) (3)

Installation at ceiling level to optimise efficiency and retainroom space

Specification to be finalised following validation of designed thermal efficiency and air tightness levels (building fabric)

Hot Water Unit

Herschel HydorNova HNW-150 litre tanklesshot water system (4)

Connection to Solar PV following phase two installation

References

(1) UK Building RegulationsApproved Document L– Conservation of Fuel and Power, UK Govt., 2021, Sec. 6.11

(2) UK Building RegulationsApproved Document L– Conservation of Fuel and Power, UK Govt., 2021, Sec. 5.2

(3) Herschel Comfort Product Range, Herschel, 2024, https://www.herschel-infrared.co.uk/productrange/herschel-comfort/

(4) Herschel HydroNova Hot Water System – Product Information, 2024, https://www.herschelinfrared.co.uk/product/hydronova-hot-water-heater/

Building Element Mechanical Ventilation & Heat Recovery (MVHR)

Existing Provision Controlled ventilation via window trickle vents

Corresponding Drawings

Performance Requirements

RetrofitApproach

HTR01 Ground Floor Plan, HTR02 First Floor Plan, HTR04 South Elevation

Measures are consistent across both UK Building Regs. and EnerPHit Standards:

Minimum Heat Recovery Efficiency = 75%

Maximum Sound Level = 25 dB(A)

Amechanical ventilation system with heat recovery is introduced to meet EnerPHit standards, where target air tightness levels of ≤1.0@50pa are delivered (see Air Tightness Strategy).

Accurate ventilation requirements to be calculated following staged air permeability testing by an accredited engineer (1).

Heatrecoveryfunctionoptimisesinternaltemperaturesandreducesdemandonprimaryheatingsystem. Unit is installed in existing airing cupboard, close to external wall to minimise distance to primary inlet/outlet and optimise efficiency.

Running ducts across loft floor and through first floor ‘posi’joists, to supply ceiling mounted vents, minimises impact on useable floor space.

‘Purging’via bottom opening windows is recommended to increase air flow during exceptionally warm periods

Component Specification

Compact unit with:

MVHR Unit

Ducting

Installation

 ≥ 75% efficiency (e.g. Zehnder Comfier 200 Luxe) (2)

 Automatic bypass function to control heat recovery during warmer periods

 Fan control

Radial design

75mm diameter (to retain 203mm posi joist depth for replacement first floor structure)

Duct routing and supply/extraction locations to be verified by system provider

Presumed single supply vent to bedrooms, living room and kitchen and extraction valve to kitchen, utility, W.C and bathroom

External inlet/outlet vents located to south elevation below eaves (extract) and at appropriate distance from retained SVPon roof face (inlet)

References

(1) UK Building RegulationsApproved Document F – Ventilation, UK Govt, 2021, Sec. 3.7 (2) Zenhder Comfier 200 Lux: Product Information, 21◦ (formerly Green Building Store), 2023, https://www.weare21degrees.co.uk/mvhr/units/zehnder/

Building Element Solar PV

Existing Provision N/A

Proposed Provision

Corresponding Drawings

Performance Requirements

RetrofitApproach

HTR04 South Elevation, HTR05 GableWall (East)

Minimum Renewable Energy Generation (EnerPHit +) = 60k kWh/m2/yr (1)

To minimise the environmental impact of post retrofit property use, the introduction of a renewable energy source is proposed. This will be specified and installed following completion of phase one retrofit works, to procure an appropriate system and output based on measured energy demand

OrientationofthepropertiesenablesroofmountedinstallationofsolarPVpanelstofacedirectsouth.

Specifying a system with integrated battery will optimise use of generated power to meet dwelling demand (with remainder provided to the grid).

Generatedpowerwillreducedemandonmainsenergyfromretrofittedinfra-redheating,ondemandhot water and MVHR systems.

Component Specification

Mounted to roof face of south elevation

Solar PV Panels

Battery

References

Output requirements and specification to be detailed by specialist following phase one retrofit works

Capacity and specification to be detailed by specialist following phase one retrofit works and Solar PV system selection

(1) EnerPHit ‘Criteria for Buildings’(version 10c), Passivhaus Institute, 2023, p. 14