Specifications
Foundations
All foundations to be formed at a minimum levl of 1000mm below ground leveland to be 600mm x 600mm square unless noted otherwise.
Wall Construction
External walls to be constructed from 100mm x 50mm SC3 timber at approx. 450mm centres lined externally with 20mm marine grade plywood over 1200g visqueen membrane or similar approved.
Plywood to be finished with 18mm cedar shiplap boarding laid vertically.
Walls to be lined internally with 20mm oriented strand boards (O.S.B) finished with 12.5mm tapered edge plasterboard with taped an skimmed joints.
Insulation to be installed between the timber studs. Either 100mm quilt or 50mm polyurethane board fitted to the external lining.
Internal walls to be constructed from 69mm x 38mm CLS timber studs at 450mm centres lined on both sides with 20m O.S.B and finished with 12.5mm tapered edge plasterboard with taped and skimmed joints to Office side only.
Damp Proof Course
Bitumous dpc to be intalled in external walls minimum 150mm above adjacent ground level and linked to existing dpc if present and to damp proof membrane within ground bearing slab.
Floor Construction
225mm x 50mm SC3 timber joists bolted together using 10mm coach bolts at 450mm centres with toothed timber connectors between. Double joists to be positioned on new pad foundations over dpc. 150mm x 50mm SC3 timber joists at 450mm centres fitted between double joists or suitable joist hangers.
Floor to be boarded out with 18mm tounge and groove chipboard over 1200g visqueen membrane or similar approved.
Windows/Doors
All windows as indicated on drawings to have a minimum of 1/20 floor area openable to all rooms, total window area to each room to be not less than 1/10 of floor area.
New windows fixed by galvanised lugs, bed cills on dpc and run mastic in reveals.
External doors with threshold and waterbar.
Bed threshold on dpc and run mastic in reveals.
Safety glazing to be installed in critical areas inside building.
These areas are as follws:-
- In doors and door side lights between finished floor level and 1500mm high.
- In internal and external walls and partitions between finished floor and 800mm high.
NOTE: all safety glazing comply with B.S.6206.
Glazing
All glazing in windows within 800mm of floor level to be saftey glass conforming to B.S.6202:1981.
All glazing in doors and side lights 300mm either side of a door within 1500mm of floor level to be safety glass as above.
Roof Construction
3 layer felt system top layer mineral felt fully bonded to 80mm polyuthrene insulation board on 18mm O.S.B deck. Deck to be laid on softwood firings to falls (1>40) fixed to 200mm x 50mm softwood joists at maximum 450mm centres.
Perimeter of roof to be fitted on 3 sides with aluminium PAP trim and on the 4th side a felt drip edge into a pvc gutter.
Ceilings to underside of joists to be 12.5mm Gyproc plasterboard skim and set.
All foundations to be formed at a minimum levl of 1000mm below ground leveland to be 600mm x 600mm square unless noted otherwise.
Wall Construction
External walls to be constructed from 100mm x 50mm SC3 timber at approx. 450mm centres lined externally with 20mm marine grade plywood over 1200g visqueen membrane or similar approved.
Plywood to be finished with 18mm cedar shiplap boarding laid vertically.
Walls to be lined internally with 20mm oriented strand boards (O.S.B) finished with 12.5mm tapered edge plasterboard with taped an skimmed joints.
Insulation to be installed between the timber studs. Either 100mm quilt or 50mm polyurethane board fitted to the external lining.
Internal walls to be constructed from 69mm x 38mm CLS timber studs at 450mm centres lined on both sides with 20m O.S.B and finished with 12.5mm tapered edge plasterboard with taped and skimmed joints to Office side only.
Damp Proof Course
Bitumous dpc to be intalled in external walls minimum 150mm above adjacent ground level and linked to existing dpc if present and to damp proof membrane within ground bearing slab.
Floor Construction
225mm x 50mm SC3 timber joists bolted together using 10mm coach bolts at 450mm centres with toothed timber connectors between. Double joists to be positioned on new pad foundations over dpc. 150mm x 50mm SC3 timber joists at 450mm centres fitted between double joists or suitable joist hangers.
Floor to be boarded out with 18mm tounge and groove chipboard over 1200g visqueen membrane or similar approved.
Windows/Doors
All windows as indicated on drawings to have a minimum of 1/20 floor area openable to all rooms, total window area to each room to be not less than 1/10 of floor area.
New windows fixed by galvanised lugs, bed cills on dpc and run mastic in reveals.
External doors with threshold and waterbar.
Bed threshold on dpc and run mastic in reveals.
Safety glazing to be installed in critical areas inside building.
These areas are as follws:-
- In doors and door side lights between finished floor level and 1500mm high.
- In internal and external walls and partitions between finished floor and 800mm high.
NOTE: all safety glazing comply with B.S.6206.
Glazing
All glazing in windows within 800mm of floor level to be saftey glass conforming to B.S.6202:1981.
All glazing in doors and side lights 300mm either side of a door within 1500mm of floor level to be safety glass as above.
Roof Construction
3 layer felt system top layer mineral felt fully bonded to 80mm polyuthrene insulation board on 18mm O.S.B deck. Deck to be laid on softwood firings to falls (1>40) fixed to 200mm x 50mm softwood joists at maximum 450mm centres.
Perimeter of roof to be fitted on 3 sides with aluminium PAP trim and on the 4th side a felt drip edge into a pvc gutter.
Ceilings to underside of joists to be 12.5mm Gyproc plasterboard skim and set.
