Flat Roof Insulation Requirements Uk

Our guides to building regulations in england adl1a 2013 building regulations.

Flat roof insulation requirements uk.

There are two basic categories of roof design. Find out more. England new dwellings. The waterproof layer is above the insulation and a vapour control layer is placed below the insulation.

Ventilation is required for these roofs. Cold deck this is where the insulation is placed between the joists rafters or in between the ceiling joists in the case of a pitch roof. In most cases there will not be a loft in a building that features flat roofing. The typical u value of an existing uninsulated flat roof is 1 5w m2k.

With a flat roof this issue does not arise but the u value constraint and the amount of insulation needed is just the same. The target should be to achieve a u value of 0 25w m2k or better. Depending on where you live in the uk snowfall must also sometimes be considered in determining the gradient of the fall. A u value of 0 55 w m k is used for cavity insulation and 0 30 w m k for internal or external wall insulation.

Room in the roof insulation. A flat roof should preferably be insulated from above. This means that your approach to insulation will differ from a standard pitched roof. This is best done when the roof covering needs replacing anyway.

Summary of flat roof building regulations. If you are replacing more than 25 of the roofing area then you will also need to replace the thermal insulation. A layer of rigid insulation board can be added either on top of the roof s weatherproof layer or directly on top of the timber roof surface with a new weatherproof layer on top of the insulation. Warm deck the type of insulation for this is usually of a rigid type and the thickness will vary depending on the manufacturer s specifications.

The saint gobain insulation uk product portfolio has a solution to help meet the requirements of the scheme. A lower u value indicates better insulation properties hence u value requirements usually specify a maximum value. A warm roof has the insulation above the structural deck which is thus kept warm. Laying flat roof insulation as a rule any roof with a pitch below 10 is classified as a flat roof.

A cold roof has the insulation placed below the structural deck which thus remains cold.