Warm Roof Insulation Depth

When specifying the insulation for the pitched roof it is important that the thickness of insulation used achieves the required u value.

Warm roof insulation depth.

Our roof conversions can be completed in just 2 3 days. The benefits of a warmer roof 2 3 day installation time. Insulation which prevents any risk of condensation and stops the build up of damp within the roof. Cold flat roofs are typically avoided as you d need to install ventilation which can prove problematic for many reasons relating to space labour costs etc.

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. 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. Ventilation is required for these roofs. Flat roof insulation thickness.

A flat roof where the insulation sits below the waterproof membrane and above the structural deck is a warm roof deck. There is a requirement when refurbishing a roof to have a minimum u value of 0 18 w m k in england and wales but for a complete re roof in wales the minimum u value required is 0 15 w m k. Warm flat roofs do not need to be ventilated as the insulation is. It should be of the maximum available thickness.

The below table shows the thickness of insulation required for a typical warm roof construction with insulation fitted above the rafters. Our u value calculator is free and simple to use for calculating u values specific to your roof construction design. The roof insulation thickness will vary dependent on the required u value. A cold roof can be cheaper as ridged warm roof insulation tends to be more expensive a warm roof is sometimes the only option when it is difficult to get the required cross ventilation rigid warm roof insulation can allow for smaller timber depths as the 50mm air gap does not have to be maintained.

If 180mm is to be installed then 100mm board might be introduced between the rafters there has to be a minimum 25mm air gap between the insulation and the underside of the tiles or slates with an 80mm board running across the rafters. Flat roof insulation always requires professional insulation and damp roofs require professional assessment before work can be carried out. With a warm roof the usual process is to split the insulation into two layers. The typical u value of an existing uninsulated flat roof is 1 5w m2k.

As only a few years ago the recommended depth of insulation was 200mm. To eliminate all condensation risks and making it a true warm roof construction. Energy efficiency grants are currently available for cold loft roof insulation. Pipes water tank and loft hatch.