A roof is defined in bs 6229 as a flat roof if it has a pitch of 10 degrees or less.
Flat roof extension building regs.
It must provide adequate protection against the elements keeping the buildings structure and interior dry.
So any timber joists that are used need to be strong enough to support this weight.
A flat roof must be strong durable and stable throughout its lifetime.
A lower u value indicates better insulation properties hence u value requirements usually specify a maximum value.
As you may imagine there is a fair amount of weight involved here in terms of boards felt etc.
To enable compliance with the requirements of the building regulations to be demonstrated full details of the new roof will be needed including materials and their dimensions and performance properties.
There must be a slope of 1 80.
The flat roof extension is more on trend than it once was and is free of the dreaded leaks that haunted this type of structure in the past.
Part h of the building regulations regarding drainage state that water should drain to one or two edges.
A qualified roofing contractor will be able to advise on this but here are some of the main guidelines.
Ventilation is required for these roofs.
Moreover the costs of a flat roof extension today are typically lower than for a pitched roof.
To comply with part l of the building regulations flat roofs must achieve u values of 0 18 w m k or lower.
To comply with part l of the building regulations 2010 all roofs to rooms except those in unheated buildings should be thermally insulated to a maximum u value of of 0 18 w m k.
Flat roof this usually consists of felting which has a slight fall to allow rain water to drain off.
When installing or repairing a flat roof you must adhere to building regulations.
This is placed over the roof joists and an board normally external ply is laid on top.
Flat roof types.
Sizes of joists needed for flat roof construction.
Old asbestos roofs are often replaced with flat roofs.
Traditionally flat roofs were constructed with cold decks where the spaces between the joists were packed with mineral wool type insulation placed above the ceiling like a.
This usually consists of felting which has a slight fall to allow rain water to drain off to enable compliance with the requirements of the building regulations to be demonstrated full details of the new roof will be needed including materials and their dimensions and performance properties.
Warm deck the type of insulation for this is usually of a rigid type and the thickness will vary depending on the manufacturer s specifications.