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.
Minimum roof pitch uk building regs.
Or else on the interior of the building just.
Choosing the right pitch.
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.
Deciding on the correct roof pitch for your home very much depends on the style of house you are building or renovating and to a lesser extent your local area.
Built up roofs require a minimum roof pitch of 1 4 12 or greater.
Slate and slate type shingles require a minimum roof pitch of 4 12 or greater.
The function of a roof is to protect the building below from the weather.
Wood shakes require a minimum roof pitch of 3 12 or greater.
Flat roof this usually consists of felting which has a slight fall to allow rain water to drain off.
Pitch roof this is where tiles or slates are used and a void is usually created underneath.
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.
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.
In order to satisfactorily fulfil this function over a period of years it must be strong stable and durable.
With regards to the pitch the building standard code bs 5534 recommends a minimum pitch of 20 0 for slate roofs.
Thermoplastic or elastomeric are the most effective and should extend up adjacent walls at least 150mm from the roof surface.
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.
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.
In addition roofs must provide good thermal insulation and prevent the spread of fire from adjacent or adjoining properties.
Flat roof drainage.
In accordance with the guidance in bs 8000 part 6 which in turn direct users to the wind uplift calculations in bs 5534.
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.
To enable compliance with the requirements of the building regulations to be demonstrated full details of the new roof will be needed including.
This will inevitably result in fixing calculations being required and complied with for all roofing projects covered by building regulations.
Mineral surfaced roll roofing requires a minimum roof pitch of 1 12 or greater.
