Minimum Slope For Flat Roof Uk

As opposed to old built up felt roofing with joins new single ply waterproof membranes are now most commonly used.

Minimum slope for flat roof uk.

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. Low pitched roofs are generally difficult to maintain and you need special materials to prevent leaks. There are two types of flat roof. 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.

Flat roofs which aren t perfectly flat require a small slope to allow for water runoff. Flat roof design guide. As the single ply roofing association spra points out this type of flat roofing is strong durable completely sealed and usually lasts at least 25 30 years. This is the basis for calculating the angle which is approximately a 1 19 degree slope.

To enable compliance with the requirements of the building regulations to be demonstrated full details of the new roof will be needed including materials and their dimensions and performance properties. You can divide roofs into these categories. 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. These roofs have a pitch less than 4 12.

It takes the manufacturer s recommendations the unique conditions of the roof as well as the skills and the expertise of the installer to arrive at the right slope. Flat roof this usually consists of felting which has a slight fall to allow rain water to drain off. This applies to general roof areas along with any internal gutters. Generally such roofs have a pitch ranging from 1 2 12 to 2 12.