Refurbishment of Social Housing Stock
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as PDF The installation of the new prefabricated roof is key to the innovation of this application. It allows for the retrofitted houses to have a high performing, insulated and airtight roof that enables thermal-bridge-free detailing from the roof eaves to externally insulated walls. It also allows the tenants to remain in occupation whilst the works are carried out to this pair of post-war semi-detached houses in Welshpool. The new roof also allows for new services (MVHR & Solar thermal & PV) to be installed in place to one of the houses, during off-site manufacture, enabling minimum disruption to residents and minimising on-site construction time. The services will be connected through the ceiling later in the process.
Retrofit for the future ZA515H
Refurbishment of Social Housing Stock : Project images
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Energy and fuel use
Measured data from renewable generation is not yet available.
Fuel use
| Pre-development | Forecast | Measured | |
| Electricity use | 3031 kWh/yr | 2148.48 kWh/yr | - |
|---|---|---|---|
| Natural gas use | 33481 kWh/yr | 3704.64 kWh/yr | - |
| Oil use | - | - | - |
| LPG use | - | - | - |
| Wood use | - | - | - |
| Other Fuel | - | - | - |
| Pre-development | Forecast | Measured | |
| Primary energy requirement | 565 kWh/m².yr | 118 kWh/m².yr | - |
|---|---|---|---|
| Annual CO₂ emissions | 106 kg CO₂/m².yr | 25 kg CO₂/m².yr | - |
| Annual space heat demand | - | 28 kWh/m².yr | - |
Renewable energy
| Electricity generation | Forecast | Measured |
|---|---|---|
| 1kWh PV Array | 850 kWh/yr | - |
| Other Renewables Tech | - | - |
| Electricity consumed by generation | - | - |
| Primary energy requirement offset by renewable generation | 92 kWh/m².yr | - |
| Annual CO₂ emissions offset by renewable generation | 19 kg CO₂/m².yr | - |
Calculation and targets
| Whole house energy calculation method | PHPP |
|---|---|
| Other whole house calculation method | - |
| Energy target | Retrofit for the Future |
| Other energy targets | - |
| Forecast heating load | 17 W/m² demand |
Airtightness
| Date | Result | |
| Pre-development air permeability test | - | - |
|---|---|---|
| Final air permeability test | - | - |
Project description
| Stage | Under construction |
|---|---|
| Start date | 07 June 2010 |
| Occupation date | 13 July 2010 |
| Location | Welshpool Powys Wales |
| Build type | Refurbishment |
| Building sector | Public Residential |
| Property type | Semi-Detached |
| Construction type | Masonry Cavity |
| Other construction type | 50mm Cavity filled poorly with |
| Party wall construction | Solid 215mm brick wall plastered either side |
| Floor area | 81.6 m² |
| Floor area calculation method | Treated Floor Area (PHPP) |
| Building certification |
Project Team
| Organisation | Ecostruct |
|---|---|
| Project lead person | Ecostruct |
| Landlord or Client | Powys County Council |
| Architect | Anne Thorne Architects Partnership |
| Mechanical & electrical consultant | |
| Energy consultant | Building Sciences Ltd. |
| Structural engineer | |
| Quantity surveyor | Ecostruct |
| Consultant | |
| Contractor | Ecostruct |
Design strategies
| Planned occupancy | Property A - 1 adult, 4 children Property B - 2 adults, 2 children |
|---|---|
| Space heating strategy | Heating from mains gas fired boiler feeding radiators, connected to Solar Thermal system. MVHR recovers radiators from gas boiler |
| Water heating strategy | Solar hot water with gas boiler-back up - Boiler takes pre-heated water from Solar store enabling full energy from solar store to be utilized. |
| Fuel strategy | Mains Gas Mains Electricity |
| Renewable energy strategy | 1 kWp photovoltaic panel array to be installed |
| Passive Solar strategy | Enlarged opening to south facing elevation. |
| Space cooling strategy | Summer/Cooling Season - Natural Ventilation (openable windows) night purging during hot weather. |
| Daylighting strategy | Triple-glazed windows. Window sizes as existing provide above minimum average daylight factors to kitchen and living/dining areas. |
| Ventilation strategy | High efficiency Whole House Mechanical Ventilation Heat Recovery system with openable windows in summer. |
| Airtightness strategy | Air tightness layer comprises membranes to internal insulated walls, roof and floor, and plaster to external insulated wall with existing plaster parged where necessary. Chimney breast filled, Membranes pre-sealed to new windows and doors, details to AECB gold standard. Precompletion testing |
| Strategy for minimising thermal bridges | Thermal bridges eliminated from eaves to ground by continuous external insulation to walls and new pre-fabricated roof. Newly installed windows ground forward to line of externally insulation to minimise/remove thermal bridges. External wall insulation taken below level of ground floor to diffuse thermal bridge to 0.012W/m.k, which has been simulated. |
| Modelling strategy | Passivhaus Planning Package 2007 (English Version), SAP 2005, Thermal Bridge Modelling |
| Insulation strategy | Externally Applied Wall Insulation - U-Value = 0.142 W/m2K Roof - Insulated timber cassettes = 0.106 W/m2K Existing solid floor insulated with 10mm aerogel = 0.38 W/m2K |
| Other relevant retrofit strategies | Retrofit to be carried out with residents in occupation during to works. Prefabrication element to retrofit. |
| Contextual information |
Building services
| Occupancy | NULL |
|---|---|
| Space heating | NULL |
| Hot water | NULL |
| Ventilation | NULL |
| Controls | NULL |
| Cooking | NULL |
| Lighting | NULL |
| Appliances | NULL |
| Renewable energy generation system | NULL |
| Strategy for minimising thermal bridges | NULL |
Building construction
| Storeys | 0 |
|---|---|
| Volume | - |
| Thermal fabric area | - |
| Roof description | NULL |
| Roof U-value | 0.00 W/m² K |
| Walls description | NULL |
| Walls U-value | 0.00 W/m² K |
| Party walls description | NULL |
| Party walls U-value | 0.00 W/m² K |
| Floor description | NULL |
| Floor U-value | 0.00 W/m² K |
| Glazed doors description | NULL |
| Glazed doors U-value | 0.00 W/m² K - |
| Opaque doors description | NULL |
| Opaque doors U-value | 0.00 W/m² K - |
| Windows description | NULL |
| Windows U-value | 0.00 W/m² K - |
| Windows energy transmittance (G-value) | - |
| Windows light transmittance | - |
| Rooflights description | NULL |
| Rooflights light transmittance | - |
| Rooflights U-value | 0.00 W/m² K |