Minimum Flat Roof Pitch Building Regulations

Flat roof slope minimum 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.

Minimum flat roof pitch building regulations.

2 see sentence 9 26 3 1 3. Metal roof shingles require a minimum roof pitch of 3 12 or greater. 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. Pitch roof this is where tiles or slates are used and a void is usually created underneath.

3 profiled metal roof cladding systems specifically designed for low slope applications are. Mineral surfaced roll roofing requires a minimum roof pitch of 1 12 or greater. Part h of the building regulations regarding drainage state that water should drain to one or two edges. This is the basis for calculating the angle which is approximately a 1 19 degree slope.

With regards to the pitch the building standard code bs 5534 recommends a minimum pitch of 20 0 for slate roofs. Clay and concrete tile requires a minimum roof pitch of 2 1 2 12 or greater. 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. The following table provides the minimum required allowable roof slope for each type of roofing material mentioned in the code.

1 see sentence 9 26 3 1 2. Asphalt shingles require a minimum roof pitch of 2 12 or greater. There are generally two types of roof construction used. Most of the time the simple answer is 150mm above the finished roof level.

Notes to table 9 26 3 1. A frequently posed question when designing flat roofs is what upstand height do i need on the face of it a simple question with one may think a simple answer. Minimum roof pitch for shingles. 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.

A qualified roofing contractor will be able to advise on this but here are some of the main guidelines. Flat roof drainage. There must be a slope of 1 80. However you can only use this pitch with built up roofing or specialized synthetic roofing.

The minimum pitch for a roof is 1 4 12 which translates to 1 4 inch rise to 12 inches of run.