On buildings up to 30 sq meters 75mm x 50mm framing timber is used and is externally cladded with 16mm matchboard timber. All of which is pressure treated, and are fixed with hot dipped galvanized nails.
On mono pitch buildings (e.g.pent sheds) with a roof span up to 2.4 meters 75mm x 50mm framing timber is used.
On mono pitch buildings (e.g.pent sheds )with a roof span between 2.4 meters and 3meters 100mm x 50mm framing timber is used.
On mono pitch buildings (e.g.pent sheds) with a roof span over 3meters 150mm x 50mm framing timber is used.
Roof trusses are generally made from 75mm x 50mm framing timber which is pressure treated, and are usually at 1200mm- 1500mm centres. On buildings over 30 sq meters structural trusses are used. These are not pressure treated and are usually at 600mm centres, and are cross braced, or are made to plan.
Trusses are generally installed one of 2 ways.
1)Wall supported trusses where the truss is placed on top of the wall panel, which gives more head room in the building, and the eaves are boxed in.
2)Wall tied trusses where they are tied to the inside wall of the building. This is the typical construction for standard shed and garages.
Roofs are generally boarded with 16mm matchboard, but on larger buildings may be boarded with 12mm or 18mm plywood.
The standard roof pitch is 15 degrees on standard sheds and 35 degrees on thatched buildings. The roof pitch can vary, but the price may vary, as scaffold may have to be used.