Choosing the right pitch.
Minimum roof pitch uk building regs.
Slate and slate type shingles require a minimum roof pitch of 4 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.
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.
The function of a roof is to protect the building below from the weather.
It also requires that roof coverings are fixed correctly.
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.
Mineral surfaced roll roofing requires a minimum roof pitch of 1 12 or greater.
Wood shakes require a minimum roof pitch of 3 12 or greater.
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.
35 is considered to be the minimum for slate and clay but if you do need to go below this interlocking concrete tiles are the best option.
In accordance with the guidance in bs 8000 part 6 which in turn direct users to the wind uplift calculations in bs 5534.
A thermal layer of fibreglass polystyrene or other insulating material should be inserted either above the roof decking the warm roof model which is suitable for homes or permanent residences.
Flat roof this usually consists of felting which has a slight fall to allow rain water to drain off.
Built up roofs require a minimum roof pitch of 1 4 12 or greater.
Wood shingles require a minimum roof pitch of 3 12 or greater.
Flat roof drainage.
Pitch roof this is where tiles or slates are used and a void is usually created underneath.
Or else on the interior of the building just.
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.
This will inevitably result in fixing calculations being required and complied with for all roofing projects covered by building regulations.
In addition roofs must provide good thermal insulation and prevent the spread of fire from adjacent or adjoining properties.
With regards to the pitch the building standard code bs 5534 recommends a minimum pitch of 20 0 for slate roofs.
To enable compliance with the requirements of the building regulations to be demonstrated full details of the new roof will be needed including.
Thermoplastic or elastomeric are the most effective and should extend up adjacent walls at least 150mm from the roof surface.
