When installing or repairing a flat roof you must adhere to building regulations.
Flat roof minimum pitch uk.
Traditionally a minimum roof pitch of 20 was recommended in bs 5534 but modern tiles and slates have now been designed for applications as low as 15.
Normally 1 80 0 72 is the recommended minimum angle for a slope and this is universal across the vast majority of flat roofing systems regardless of the materials that they incorporate.
It is uncommon to find a roof below 15 but for those very low pitch applications there are interlocking clay pantiles available suitable for use down to 12 5.
If flat roofs are to work well they have to have a slope known as a fall to shed rainwater.
In order to achieve this drop a slightly steeper angle of 1 40 1 44 should be the aim when installing a flat roof as this accounts for surface deviations and material deflection among other things.
To enable compliance with the requirements of the building regulations to be demonstrated full details of the new roof will be needed including.
Flat roof drainage.
The fall should never be less than 1 80 and preferably about 1 40.
There is also the scope to incorporate a green roof onto the flat structure.
Part h of the building regulations regarding drainage state that water should drain to one or two edges.
Flat roof design guide.
There must be a slope of 1 80.
A pitch of 10 degrees or less is typically regarded as a flat roof.
This applies to general roof areas along with any internal gutters.
There are several methods of building in a fall.
A flat roof is more likely to allow rain to pool and this can cause damage especially if the roof is made of a porous substance like wood.
Flat roof this usually consists of felting which has a slight fall to allow rain water to drain off.
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.
What pitch is a flat roof.
Pitch roof this is where tiles or slates are used and a void is usually created underneath.
Minimum roof pitch for shingles.
A qualified roofing contractor will be able to advise on this but here are some of the main guidelines.
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.
