Near Zero - Typical Specification for Self build

	Typical Building Specification

	Foundations All foundations are subject to site investigation and soil / ground bearing pressures and are therfore specialy designed to suit each individual project. All our house designs can be built off any type of foundation.
	External Walls Constructed using loadbearing stuctural insulated panels (SIPs) with an injected polyurethane core and OSB/3 sheathing (OSB/3 to BS EN 300 : 1997). The panels will have a U-value no less than 0.2 W/m².k. The panels are connected by the use of OSB/3 splines located in preformed rebates within the polyurathane core or a C25 grade timber post where required to carry additional loads. The panels are constructed off a C24 grade treated timber sole plate over a highload damp proof course with a bottom plate to locate within the core rebate. All joints are filled with expanding polyurethane foam during construction to form air and watertight joinst throughout. All timber to timber joints to have a compressed seal of low modulus silicone sealant. Panels to be covered externally with moisture permeable breather membrane securely fixed with treated softwood battens. All joints to have minimum 150mm lapped joints. Internal Walls Constructed using 63 x 38 C16 grade softwood timber framing with vertical framework at maxiumum 400mm centres. The frame is sheathed on both sides with 11mm thick OSB/3 to give structural stability and a continuous fixing face throughout. Internal walls around kitchens and bathrooms to have a rockwool quilt accoustic insulation (min. 10kg /m³) layed between the vertical studs to inhibit the passage of sound.
	Intermediate Floors Constructed using 22mm thick OSB/3 or P5 particle board decking screwed and glued down to enginered timber floor joists at centres determined by the structural engineer. Engineered floor joists to be securely fixed using appropriate galvanised joist hangers specified by the structural engineer. Where required to inhibit the passage of sound through the floor a Rockwool quilt accoustic insulation (min. 10kg /m³) is fixed between the floor joists. Roof Constructed using loadbearing stuctural insulated panels (SIPs) with an injected polyurethane core and OSB/3 sheathing (OSB/3 to BS EN 300 : 1997). The panels will have a U-value no less than 0.2 W/m².k. The panels are connected by the use of OSB/3 splines located in preformed rebates within the polyurathane core or a C25 grade timber post where required to carry additional loads. Panels to be covered externally with moisture permeable breather membrane securely fixed with treated softwood battens. All joints to have minimum 150mm lapped joints. Ridge beams and purlins where required are to be specified by the structural engineer as 'Paralam' or 'Glulam' beams as appropriate.
	Windows and Doors Nordan inward opening prefinished timber windows and doors with 24mm thick Low 'E' double glazing to give a minimum area weighted U-value of 1.6 W/m².k or 36mm thick Low 'E' triple glazing to give an area weighted U-value of 1.0 W/m².k. Trickle ventillation to be included only if machanical ventillation with heat recovery is not installed. All glass within 800mm of finish floor level, within or adjacent doors to be toughened both leaves to BS6206 and have the BS6206 mark to show compliance. Windows to first floor habitable rooms to have opening leaf to facilitate egress from the building in case of emergency. All windows to be 'Secure by Design' standard. Internal Finishes Internal walls throughout are finished with 2 layers of 12.5mm thick foil backed tappered edge plasterboard screw fixed back to the wall panels with taped, filled and sanded joints ready to receive decoration. The first layer of plasterboard is to be fixed butt up to any first fix galvanised electrical back boxes leaving a void above and below the box for electrical cables. The second layer is fixed over the void and a hole cut to expose the galvanised steel electrical back box to allow for cable connection to socket fronts. Ceilings are finished with 15mm thick soundblock tappered edge plasterboard screw fixed to the underside of the floor joists with tapped, filled and sanded joints ready to receive decoration.
	External Finish Options Render - 3 coat polymer render applied onto min 12mm thick cementitious particle board screwed back to 50 x 25mm treated softwood vertical battens at max. 600mm centres. Timber Cladding - Vertical or horizontal timber cladding of cedar, larch or douglas fir precured from sustainable source fixed back to 50 x 25mm treated softwood vertical battens at max. 600mm centres. Reclaimed Natural Stone - to size, colour and lay to suit individual project. Minimum 50mm cavity between stone and panel with stone tied back to panels using Simpson strong-tie BTS4 wall tie kits. Minimum 7 ties per m². Reclaimed brick - size, colour and lay to suit individual project. Minimum 50mm cavity between brickwork and panel with brick tied back to panels using Simpson strong-tie BTS4 wall tie kits. Minimum 7 ties per m². Tile roofing - Concrete, clay or natural slate roofing fixed back to treated softwood tile battens at pitch to suit tiles fixed back to 50 x 25mm treated softwood counter battens at maximum 600mm centres. Eaves and ridge ventillation to be maintained throughout using proprietry accessories for the tiles used. All flashings to be code 4 lead and to have a minimum upstand of 150mm above the roof covering and be dressed into wall finish by a minimum of 25mm and sealed. Zinc Standing Seam roofing - To specialist design and details. Sedam / grass roof system - To specialist design and details.
	Plumbing & Electrics All new plumbing and electrical work to be designed, installed and commisioned by a competent and qualified engineer to exceed minimum standards. All new heating and domestic pipework to be fully insulated. All heating systems to be fitted with thermostatic controls and where gas energy is used by a Corgi registered engineer. Kitchen and bath trap and waste to be min 40mm dia. Basin trap and wasteto be min 32mm dia. Plumbing for washing machines and dishwashers to have minimum 40mm dia tra and waste. All electrical work to be carried out by an AD Part P registered engineer. Positions of sockets, lighting and switches to clients requirements fixed into 25mm deep galvanised steel back boxes with all cables retained within plasterboard or floor / ceiling voids. All installed to exceed minimum standards. All renewable energy technologies to be fully integrated within electrical design. Fire and Smoke Detection All houses are provided with mains operated and linked fire and smoke detection ceiling mounted with battery backup to BS5446 positioned in circulation routes at least 300mm away from walls or light fittings. Rainwater Goods All rainwater gutters, downpipes and accessories to be pressed metal or aluminium with a powder coat or anodised finish all discharging into back inlet gullies connected to rainwater harvesting system or drainage.