Flat Roof Insulation Requirements Uk

Laying flat roof insulation as a rule any roof with a pitch below 10 is classified as a flat roof.

Flat roof insulation requirements uk.

Our guides to building regulations in england adl1a 2013 building regulations. A lower u value indicates better insulation properties hence u value requirements usually specify a maximum value. Achieving a u value of 0 20w m meaning your roof will be better insulated than your walls will need 120mm thickness of rigid foam or 200mm of mineral wool or natural insulation. With a flat roof this issue does not arise but the u value constraint and the amount of insulation needed is just the same.

Summary of flat roof building regulations. There are two basic categories of roof design. The target should be to achieve a u value of 0 25w m2k or better. A flat roof should preferably be insulated from above.

This is best done when the roof covering needs replacing anyway. 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. Find out more. 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 warm roof has the insulation above the structural deck which is thus kept warm. Ventilation is required for these roofs. In most cases there will not be a loft in a building that features flat roofing.

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. A cold roof has the insulation placed below the structural deck which thus remains cold. The typical u value of an existing uninsulated flat roof is 1 5w m2k. U value of a flat roof to comply with part l of the building regulations 2010 all roofs to rooms except those in unheated buildings should be thermally insulated to a maximum u value of of 0 18 w m k.

If you are replacing more than 25 of the roofing area then you will also need to replace the thermal insulation. This means that your approach to insulation will differ from a standard pitched roof. The waterproof layer is above the insulation and a vapour control layer is placed below the insulation. The saint gobain insulation uk product portfolio has a solution to help meet the requirements of the scheme.

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.