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.

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. Hitting amazing levels of 0 13w m will need 300mm of mineral wool or 180mm of rigid foam. Flat roof insulation always requires professional insulation and damp roofs require professional assessment before work can be carried out. In this case ventilation is required and the roof can still become wet with condensation which may cause materials to decay.

In most cases there will not be a loft in a building that features flat roofing. Lay 12mm of plywood or osb board across the timber joists as a base for the flat roof build up. 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. It should be of the maximum available thickness.

Find out more. There are two types of flat roof. Ventilation is required for these roofs. This means that your approach to insulation will differ from a standard pitched roof.

Insulating a flat roof is relatively simple in terms of what materials you need and the steps taken to complete the job. The typical u value of an existing uninsulated flat roof is 1 5w m2k. Insulating between the joists of your loft will keep your house warmer but make the roof space above colder. Flat roof insulation thickness.

Cold roofs and warm roofs. Our guides to building regulations in england adl1a 2013 building regulations. Install a vapour control layer to reduce the risk of condensation and moisture compromising the flat roof structure. The chosen insulation laid on top of this should be able to take the weight of anything put above it on the roof without compression or protected from compression by further sheeting.

Cold roofs have the waterproof layer placed directly onto the roof deck and the insulation inside the roof just above the ceiling. England new dwellings. 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. 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.

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. Insulation can also help to limit condensation and contribute to acoustic insulation depending on the type of insulation used. Pipes water tank and loft hatch.