| Planned occupancy | All 6 (henceforth labelled A-F) of the properties are 3 bedroom, currently tenanted. The occupancies vary and represent the extremes of social housing stock, rather than plan any different occupancy the proposals are to suit these households. Considerable experience of tenants participation in design suggests that this variety will be attractive to future tenants.. There is a young family with one child. A single mother with 3 children, 2 of whom are reported to have asthma. There is a shared tenant left on occupation who is also very ill. A mother and adult daughter. 2 pensioners and their son. |
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| Space heating strategy | All of the properties will be heated by their existing radiators. In properties A, B, C and D they will be heated by gas boilers, in B this will be supplemented by some heat from the large solar thermal array, calculated to be 25%. E and F will both have biomass stoves in the living rooms, one burning pellets, the other logs. They will both be supplemented by the same size solar arrays on the roof to ensure that there will be no need to light the stoves during the warmer months, the size of the thermal stores will provide a buffer for poor weather, aiming to confine the period during which the stoves will need to be lit to October to March. |
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| Water heating strategy | B, E and F properties will get 85% of their hot water from the solar arrays. In E and F this will be supplemented by the biomass stoves as they have Clean Air act approval despite having back boilers. Property B will have the hot water topped up by the heating side of the gas boiler's operation topping up the thermal store as necessary. The rest of the properties will use the gas combination boilers |
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| Fuel strategy | Main gas and mains electricity. The fuel for the biomass stoves will be supplied through the Dearne Valley Ecovision as part of building up local supply chains of this kind of thing. |
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| Renewable energy strategy | A, C and D will have photovoltaic arrays of 1.2kW, 2.2kW and 1kW respectively to offset the necessary emissions |
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| Passive Solar strategy | In 3 of the properties while the windows are being replaced the openings are remaining unchanged. However the new windows will be fixed to the front of new timber reveals to come nearly flush with the outside surface of the render. This will maximise solar gain as much as is possible. In the other 3 properties the windows were recently replaced so only the glazing units themselves are being replaced, so there will be little difference in the solar gain strategy. However the solar gains in all 4 properties will form a much more significant part of the heat requirements of the properties due to the very substantial levels of insulation achieved. |
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| Space cooling strategy | A, E and F will have stack effect ventilation so the stack will increase in force during hot periods this should produce the required cooling. C will supplement the ventilation with a temperature actuated loft hatch and permanent vent to the retained chimney just below the ridge. Together with the existing windows this will provide stack effect ventilation during heat waves without needing to undermine security with windows open all night. B and D will have their night purge on the MVHR supplemented by the same loft and vent combination as C. |
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| Daylighting strategy | The existing windows opening are not being changed. Moving the windows to the outside of the envelope will mitigate the reduction in sky view as a result of the thicker wall in the case of A, B and E this will be comapred with tenant perceptions in C, F and D. |
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| Ventilation strategy | C will rely on existing natural ventilation supplemented by the loft stack system described above. A, E and F will be fitted with a Passivent passive stack ventilation system. E will have the underfloor pre-heat to see if the position of inlet air deters occupants from disabling the trickle/stack vents B and D will have whole house ventilation, again supplemented by the loft stack system when necessary. |
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| Airtightness strategy | The new double seal windows will be pre-fitted and shop sealed to the new reveals which will be fitted prior to the external insulation allowing them to be taped to the existing masonry outside and sealed with a mastic seal internally. The render is a modified polymer and will be carried past the woodfibre insulation making a seal with the Foamglas below ground insulation. At roof level it will be sealed to the eaves board vertically and back to the sole plate internally. The ceilings will be resealed and the hatches are all to be replaced with actuated and sealed insulated ones. Floors are ground bearing concrete under the timber. |
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| Strategy for minimising thermal bridges | The window detail described above ensures a continuous insulation all the way to the window. The front door detail will not come right to the fron but will protrude past the masonry to ensure no bridging. The insulation is continuous 600mm past the floor edge. The ceilings are being topped up with Warmcel so filling gaps. The loft hatch is being replaced with an insulated one achieving 0.35W/m2K. On the gables the insulation will be carried past to form a parapet and so avoid any bridging. The external insulation at the eaves will be joined to the internal ceiling insulation with a high efficiency insulation as the accredited detail. |
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| Modelling strategy | |
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| Insulation strategy | Ceiling rafters are to be built up into 400mm timber truss beams. Warmcel will be poured over the existing insulation up to the new rafter tops and then boarded in to prevent disturbance and compression. Walls will be insulated externally with 200mm of Udireco wood fibre insulation - a compressible layer bonded to a rigid board that takes a modified polymer diffusion open render system. Below 300mm above ground the wood fibre will be replaced by 200mm of Foamglas slabs. Concrete floors will either be replaced with 200mm of Misapor granular foamed glass under a new slab or externally insulated by a Foamglas filled trench. Suspended timber floors will be insulated with Misapor at ground level or with batts pushed between the joists when over the small cellars. The doors will be insulated, all the windows triple glazed. |
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| Other relevant retrofit strategies | The tenants have been involved in picking the measures from the start and they have been tailored to suit their preferences where possible. They have been fully explained, and further support visits are planned. The intention is that in C, F and D the tenants will remain in the properties throughout, in the case of C the intention is to only enter the house over a 2-3 days period. The tenants of A, B and E weclomed the new floors so will be temporarily rehoused while this part of the work is carried out. |
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| Contextual information | |
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