Building a flat roof involves the use of steel or roofing timber laid across two walls. The steel or rolled steel joists are usually built into one or both walls to give added stability to the roof structure.Continue Reading
The roofing timber is then laid on top of the steel or cut into them. Space the roofing timber at a specified distance apart; typically about 16 inches depending on the span or width they are covering and the surface. In most cases, OSB wood or plywood is used as the covering. OSB wood or plywood is also called Stirling board.
The wood used in flat roofing need to be waterproofed. Lay boards across the joists, and use a rubber or felt to cover the boards to make them waterproof. Grooved and tongue decking boards are essential where two boards meet to make the joint strong enough to support the flat roof load. A flat roof is needed when local regulations do not allow the height required for a pitched roof because it may obscure a neighbor's light or view. Additionally, a pitched roof is not appropriate for an extension because it obscures light to the homeowners' windows.
Using a flat lean-to roof makes it easy for water to flow from the building into new gutters connected to existing drainage systems. New flat roofs are used to replace old roofs. For instance, corrugated tin roofs or asbestos are not allowed under building regulations and must be replaced by flat roofs.Learn more about Carpentry