BISF Steel Frame House - 80% Carbon Dioxide emmision reduction through whole house upgrade approach including innovative technologies
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as PDF Existing: Steel frame with render and steel cladding; Blockwork and timber frame side extension; Steel shingle roof. Proposed: Existing render and steel cladding removed; New sheathing board, insulation & render cladding; Wall, roof & floor insulation to side extension; Main roof insulation increased to 350mm; Triple glazed uPVC windows; High efficiency gas boiler serving radiators; Flue gas heat recovery; LED lights with 50k hours guaranteed max light output; Decentralised whole house ventilation; 2.7kWp PV and 3.0m2 solar thermal panels; AA++ appliances; Smart metering with display; Shower water heat recovery; Reduced water consumption
Retrofit for the future ZA145M
BISF Steel Frame House - 80% Carbon Dioxide emmision reduction through whole house upgrade approach including innovative technologies : 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 | 2751 kWh/yr | 1406 kWh/yr | 4913 kWh/yr |
|---|---|---|---|
| Natural gas use | 18587 kWh/yr | 9593 kWh/yr | 2509 kWh/yr |
| Oil use | - | - | - |
| LPG use | - | - | - |
| Wood use | - | - | - |
| Other Fuel | - | - | - |
| Pre-development | Forecast | Measured | |
| Primary energy requirement | 321 kWh/m².yr | 165 kWh/m².yr | 172 kWh/m².yr |
|---|---|---|---|
| Annual CO₂ emissions | 62 kg CO₂/m².yr | 32 kg CO₂/m².yr | 39 kg CO₂/m².yr |
| Annual space heat demand | - | 79 kWh/m².yr | - |
Renewable energy
| Electricity generation | Forecast | Measured |
|---|---|---|
| 2.7kWp PV | 1914 kWh/yr | - |
| Other Renewables Tech | - | - |
| Electricity consumed by generation | - | - |
| Primary energy requirement offset by renewable generation | 111 kWh/m².yr | 172 kWh/m².yr |
| Annual CO₂ emissions offset by renewable generation | 19 kg CO₂/m².yr | 39 kg CO₂/m².yr |
Calculation and targets
| Whole house energy calculation method | SAP |
|---|---|
| Other whole house calculation method | - |
| Energy target | Retrofit for the Future |
| Other energy targets | - |
| Forecast heating load | - |
Airtightness
| Date | Result | |
| Pre-development air permeability test | - | 15.82m³/m².hr @ 50 Pascals |
|---|---|---|
| Final air permeability test | - | 12.51m³/m².hr @ 50 Pascals |
Project description
| Stage | Occupied |
|---|---|
| Start date | 01 March 2010 |
| Occupation date | 16 April 2010 |
| Location | Cambridge Cambridgeshire England |
| Build type | Refurbishment |
| Building sector | Public Residential |
| Property type | Semi-Detached |
| Construction type | Steel frame |
| Other construction type | Render and steel cladding |
| Party wall construction | 250mm block / block cavity |
| Floor area | 88 m² |
| Floor area calculation method | Actual Floor Area (SAP) |
| Building certification |
Project Team
| Organisation | Cambridge City Council |
|---|---|
| Project lead person | Cambridge City Council |
| Landlord or Client | Cambridge City Council |
| Architect | PRP Architects |
| Mechanical & electrical consultant | N/A |
| Energy consultant | PRP Environmental |
| Structural engineer | Scott Wilson |
| Quantity surveyor | |
| Consultant | CDM Coordinator: PRP Project Services |
| Contractor | Hill Partnerships ltd |
Design strategies
| Planned occupancy | Currently one elderly resident, but potential for family with three children |
|---|---|
| Space heating strategy | Gas fired boiler with flue gas heat recovery feeding radiators |
| Water heating strategy | Solar hot water with gas condensing boiler back up |
| Fuel strategy | Solar thermal hot water with mains gas back up, PV panels and mains electricity |
| Renewable energy strategy | 2.7kWp polycrystaline photovoltaic array; 22.5sq.m, 3.0sq.m solar thermal panels |
| Passive Solar strategy | The house faces almost exactly due west and has some large windows on the west side. Fenestration patterns will remain as existing and adjustments have been made to glazing g-value to compensate for potential overheating on the west facing elevation. |
| Space cooling strategy | Natural ventilation via openable windows; room layouts allow for cross ventilation and cooling. Adjustments to glazing g-value to guard against overheating. |
| Daylighting strategy | The house already has good natural daylight through large windows. It was designed at a time when daylight and fresh air where important aspects of new beginings in post war housing development. |
| Ventilation strategy | Natural ventilation via openable windows, plus a decentralised whole house system using continuously running low energy fans drawing air out through wet rooms. |
| Airtightness strategy | Sheathing board with foam / render overcladding and careful detailing around windows and doors to minimise air leakage. High performance seals to windows and doors. Draught sealing around the loft hatch. Ventilation equipment checked for air leakage prior to commissioning and careful detailing around sockets and all other penetrations. Instruction to operatives on best practice at contract stage. |
| Strategy for minimising thermal bridges | Minimisation of thermal bridges at design stage by careful detailing of all material and component junctions to ensure continuity of insulation and thermal performance. House steel frame adjusted locally to allow new windows to be supported in line with overcladding. Continuation of overcladding to below ground level to protect the concrete slab edge. Instruction to operatives on best practice and careful monitoring on site during construction. |
| Modelling strategy | Whole house modelling was undertaken using SAP (with NHER Plan Assessor software) in conjunction with the Extended SAP worksheet. EDSL TAS was used to undertake an overheating analysis. AutoCAD produced plans and elevations were used to assist with visualisation and detailed design. |
| Insulation strategy | Ground floor - new timber suspended in living room, 25mm nanogel blanket Resultant U-value 0.43 W/m2K Exposed front, rear and gable walls - 200mm Permarock external insulation Resultant U-value 0.11 W/m2K Sheltered house wall in lean-to lobby & store - 50mm Spacetherm 0.21 W/m2K Stud external wall - 50mm phenolic board plus 50mm Spacetherm 0.17 W/m2K Pitched roofs with flat ceiling - Top up to 350mm mineral fibre quilt Resultant U-value 0.12 W/m2K Windows - Replacement uPVC triple glazed low-e Resultant U-value 1.1 W/m2K Doors - Replacement uPVC with triple glazed low-e Resultant U-value 1.5 W/m2K |
| Other relevant retrofit strategies | Our proposals are designed to be carried out with residents remaining in occupation. Considering the wider application of Retrofit it will not be practical or economically viable on a large scale to decant residents while the work is in progress. Pre commencement discussion and engagement with residents, plus regular monitoring during and after the works, will help to minimise the degree of inevitable inconvenience. |
| Contextual information | The particular form of steel frame construction of this house and the well documented defects that have affected other similar homes have influenced our decision to remove the detriorating and unstable external finishes and substitute a structurally sound and thermally efficient envelope. The poor quality of original internal linings have also influenced the choice of a robust and stable cladding. |
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 | |
|---|---|
| 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 |