This is the backing detail.
Scope of work:
General Notes
• All screws, nails, ferrous metal straps and other misc. ferrous metalwork to be either zinc plated or galvanised.
• Copies of commissioning certificates (including electrical system) to be deposited with Building Control surveyor as soon as they are available.
• Demolition of existing unusable floors to commence, all debris removed from site.
Foundations
• 450mm wide strip foundation Gen3 concrete trenchfill of perimeter walls.
• Excavate sub-soil to a depth of 1.25m below existing ground level & replace with well-graded granular stone, compacted as required.
• Concrete vibrated into position to remove all air pockets.
• Concrete slab to be poured to 150 thick. Concrete grade RC28/35 reinforced concrete. A252 mesh applied in top & 35 cover. 150 insulation on 1200 gauge polythene DPM on 150 compacted granular material (stone) bound with sand.
Underpinning
• 900 x 900 Underpinning of existing 7 column bases, size & depth to vary as required.
• Underpinning to be carried out in 2 sections per base location.
• Excavate & cast before moving on to next stage.
Damp proof course
• Marley Homegard Housing Grade Pitch Polymer DPC to be placed horizontally around perimeter no. 3 courses above ground level; 450mm laps to joints.
Ground floor construction
• Latex self-levelling screed to be placed across whole floor to ensure that floor levels are equal; floor finishes are to be installed outside the terms of the main contract.
• 75mm cement: sand structural topping; powerfloat finish (containing underfloor heating pipework).
• Polythene separating level between top of insulation and underside of structural topping.
• 1000 gauge polythene Damp Proof Membrane; DPM is to be carried across cavity to full width of wall with polythene cavity trays above; all DPM joints and penetrations are to be taped with duct tape.
External walls
• Allowance for outer skin of walls to be cladded in larch.
• 100mm cavity full filled with Celotex insulation.
• 12.5mm plasterboard and skim secured to timber studs.
• Cavity tray to be provided one course above DPC to enable any moisture in cavity to be shed outwards.
Roof Structure
• Asbestos roof removed & insulated with Kingspan tin & timber purlins.
• Wall plates to be 75 x 100mm treated SW strapped to tops of walls in accordance with Approved Document A of The Building Regulations 2010 (as amended).
• 6 Skylights to be installed.
Roof joinery
• All roof joinery to be constructed using wood grain uPVC cladding material. Optional.
• 22mm thick fascia boards and 15mm thick soffits; uPVC profiles.
• Deep flow uPVC Gutters.
• Downpipes are to discharge directly to gulleys.
External joinery
• All external joinery is to be uPVC; precise door style and glazing options for front door to be agreed with client. However as per plan uPVC single front door & screen allowed for.
• All joinery to achieve a U Value of 1.4W/m2k.
• All doors and windows are to be installed by specialists and covered by FENSA Certification.
• All habitable rooms are to be supplied with 8000mm² background ventilation, all other rooms to have 4000mm² background ventilation; provided via trickle ventilators, all trickle ventilators must be capable of being closed.
• All glazing to be 4-16-4mm Pilkington “K” Glass sealed double glazed units.
• All glazing below 1500mm in doors (800mm elsewhere) and within 300mm of door openings to be Kitemarked toughened glass to comply with BS6206: 1981 clause 5.3.
• Allowance for up to 10 aluminium windows.
• Entire gable to be aluminium & glass openings as per drawing – sliding doors.
Ceilings
• All ceilings to be 12.5mm plasterboard and skim throughout.
Internal joinery
• 25mm thick MDF window board.
• 75mm architraves and 150mm skirting boards to be fixed with lost head nails
Internal finishes – floors
• Concrete floor to have a latex levelling compound applied in readiness to receive floor finishes; latex chosen to be suitable for the installation of engineered wood flooring, ceramic and quarry floor tiles.
• All carpeting/flooring to be carried out outside the terms of the main contract.
Kitchen
• Kitchen to be fully discussed with client however a PC sum of £15,000 has been allowed for a based on mid-range standard kitchen from Howdens & won't be fully determined until spec of kitchen is confirmed.
• Kitchen to be fitted with extractor hood above cooker with an extraction rate of 30l. per second.
• All extraction fans are to be vented to atmosphere with brown plastic vent grilles.
Bathrooms x3
• Bathrooms to be fully discussed with client however a PC sum of £4,900 each has been allowed for a based on mid-range standard bathroom & won't be fully determined until spec is confirmed.
Electrics
• Layout of lighting, light switching and socket outlets to be agreed with client on site; allow for locating an external socket outlet on the rear of the building as well as a light fitting adjacent to the front door.
• All electrical works to be carried out by an electrical engineer who can self certify the installation upon completion of works.
• Mains Operated smoke alarms with battery backup to be placed in new porch on Ground Floor.
• Light fittings and electrical sockets to be positioned as directed by client on site within the parameters of Approved Document M; all electrical outlets to be manufactured by MK.
• 50% of installed light fittings and bulbs to be energy efficient type to comply with Approved Document L1.
• PC sum allowed £10,500 for electrics.
Facilities for disabled persons
• All light switches are to be no higher than 1200mm above finished floor level.
• Electricity outlets, TV aerial and telephone points are to be no lower than 450mm above finished floor level.
Foul Drainage
• Access is to be maintained to all above ground waste pipework.
• 110mm diameter stub soil pipe to be placed in corner of roof; fitted with a Durgo type air admittance valve 1200mm above internal floor level; soil pipe to discharge to manhole immediately outside porch extension and in turn to new treatment plant.
• Foul drainage pipework to fall at a uniform rate of 1 in 60; pipework to be surrounded with 225mm pea gravel; concrete lintels to be provided where soil pipework passes through walls below ground level.
• Treatment plant to be installed as per plan.
• Waste pipework from back inlet gulley to discharge via 110mm diameter pipework to a system of proprietary plastic inspection chambers and eventually to existing site foul drainage system.
• 110mm diameter plastic drainage pipes are to be laid to falls of 1 in 60; surrounded with 225mm pea gravel.
• Proprietary plastic inspection chambers are to be used at pipe intersections and changes of direction; inspection covers and frames are to be rated to withstand both pedestrian and light vehicular traffic; inspection chambers are to be bedded and installed in strict accordance with manufacturer’s guidelines.
Plumbing and Heating
• Air source heating and hot water system to be installed; all works to be specified and installed by a specialist company.
Smoke and heat rise alarms
• Mains operated heat rise detector is to be placed in kitchen.
• Alarms to be fitted in strict accordance with manufacturer’s instructions.
Internal finishes – walls and ceilings
• All internal walls to be plastered & finished ready to paint.
• Internal walls to be painted with one sealing coat and two coats DULUX emulsion paint; colour scheme to be wall in Buttermilk or Magnolia, ceilings Pure Brilliant White unless instructed otherwise by clients.
• MDF Skirting throughout.
Surface water drainage
• Rainwater downpipes to discharge to surface water drainage system via Hepworth trapped gulleys.
• 110mm Hepworth ring seal (self coloured black) uPVC surface water drainage to fall at a rate of 1 in 80; to discharge to soakaways within garden; soakaway provision required to be sited a minimum 5.0m from dwellings.
Drainage pipes to be bedded and surrounded with 150mm pea gravel; drainage pipes less than 400mm below ground level to be encased in 100mm Gen 3 concrete.