2 asphalt and gravel or coal tar and gravel roofs may be constructed with lower slopes than required in sentence 1 when effective drainage is provided by roof drains located at the lowest points on the roofs.
Minimum flat roof pitch building regulations.
3 profiled metal roof cladding systems specifically designed for low slope applications are.
Part h of the building regulations regarding drainage state that water should drain to one or two edges.
According to the international building code the typical built up flat roof that uses tar or asphalt goes by the guideline that for every foot 12 inches of a flat roof a minimum of inch must step up or down.
The actual specification required for a compliant building and necessary building fabric u value targets may vary depending on the actual overall proposed specification and the outcome of the energy.
Wood shakes require a minimum roof pitch of 3 12 or greater.
Building codes and roofs.
Roof slope equivalents as rise.
A qualified roofing contractor will be able to advise on this but here are some of the main guidelines.
Complete list of roofing types.
1 see sentence 9 26 3 1 2.
Roof pitch multiplier table.
The below drawing shows the u value requirements set out for new properties in the building regulations for each element walls floors and roofs.
According to bs 6229 bs 8217 flat roofs should be designed with minimum falls of 1 40 to ensure a finished fall of 1 80 can be achieved allowing for any inaccuracies in the construction.
Slate and slate type shingles require a minimum roof pitch of 4 12 or greater.
Built up roofs require a minimum roof pitch of 1 4 12 or greater.
There must be a slope of 1 80.
This is the basis for calculating the angle which is approximately a 1 19 degree slope.
A correctly build flat roof will drain the rainwater quickly and effectively into the gutters without allowing water to collect in depressions and pond on the surface of the roof leading to the build up of silt deposits on the roof and stresses in the membrane when the water freezes a small amount of ponding is inevitable and it should not reduce the.
When installing or repairing a flat roof you must adhere to building regulations.
Flat roof drainage.
Notes to table 9 26 3 1.
To enable compliance with the requirements of the building regulations to be demonstrated full details of the new roof will be needed including.
2 see sentence 9 26 3 1 3.
But since there is still a wide variety of slate roofing systems there are occasions when the minimum pitch can go down to as low as 15 0 depending on the uniqueness of the roof.
Flat roof this usually consists of felting which has a slight fall to allow rain water to drain off.
It is a requirement of building regulation part h that adequate provision is made for rainwater to be carried from the roof of the building.
Run in degrees and as percentage the minimum roof slope allowed by code for any type of roof is in 12 applicable only to coal tar pitch roof systems.
Wood shingles require a minimum roof pitch of 3 12 or greater.
Degrees to pitch rise in run table.
