As the plot is flat, free of contamination and surface obstructions, a strip foundation will be used, together with a pre-cast beam and block floor, insulated in accordance with manufacturer’s instructions. This is a relatively straightforward roof and will be designed / constructed as an integral part of the timber frame package. Special attic trusses will be specified to provide a structural roof and floor in the same component (Appendix C).
This detail is cost effective and will allow conversion of the attic space into habitable rooms, should this be required at a later date. The roof will be covered with concrete interlocking roof tiles which will be nailed to softwood treated battens laid over a breathable membrane, in accordance with building regulations and Housing Association criteria. Forticrete “Gemini” concrete tiles will be specified because they are award winning, competitively priced tiles guaranteed for 60 years (Appendix D).
A proprietary eaves and ridge roof void ventilation system will be used. Rainwater goods will be plastic – gutters will be ogee and downpipes will be round. The roof tile and brick colour will be sympathetic towards the building materials in the surrounding area and in accordance with any planning requirements. The roof space will be accessible through an insulated, draught-proof hatch. 400mm mineral fibre quilt insulation will line the roof space above the ceiling.
Timber is an organic, non-toxic and naturally renewable building material and in the UK is sourced from well managed softwood forests. Timber products have lower embodied energy and are recyclable, having less impact on the environment than masonry products. Timber is effectively carbon – neutral material and has the lowest CO2 cost of any commercially available building material. About 77% of the energy used in the production of wood products comes from wood residues and recovered wood. In contrast, concrete uses five times more energy to produce than timber.
(1) All timber used in the construction of this bungalow will have FSC or equivalent certification. This is one of the most rigorous checking systems for timber and it ensures that forests from which trees are taken are sustainably harvested and that forests are replanted. Timber will be treated only where essential for the circumstances and carried out industrially prior to use. The use of toxic chemicals and hazardous materials including paints containing lead will be avoided. Asbestos based products will not be used.
Wherever possible, products in which formaldehyde is used in the manufacturing process will not be used. Appliances containing CFCs, HFCs and HCFCs will not be used. (4) In addition, the bungalow will be more energy efficient and environmentally friendly because: The walls and roof will be insulated and have a U value of 0. 25. (The U value is a measurement that describes how well building materials protect against heat loss. A typical brick cavity has a U value of 1. 21). The improved insulation will reduce heating costs and conserve energy.