Warm Deck Flat Roof Insulation Thickness

Warm deck flat roof the type of insulation for this is usually of a rigid type and the thickness will vary depending on the manufacturer s specifications.

Warm deck flat roof insulation thickness.

18 thickness of deck. The target should be to achieve a u value of 0 25w m2k or better. This is placed over the roof joists and an board normally external ply is laid on top. The below u value table shows the required insulation thickness based on the typical warm flat roof construction outlined.

To calculate u values and insulation thickness specific to your project use our free online u value calculator. Others would treat even steeper pitches as flat roofs. This is placed over the roof joists and a. The joist size depends on your span but assuming you are going out say 3m or so your joists would be about 150 deep.

A flat roof where the insulation sits below the waterproof membrane and above the structural deck is a warm roof deck. Thickness varies according to the manufacturer s specifications. There are two basic categories of roof design. Min 125 thickness of insulation board then finish on top.

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. It should be of the maximum available thickness. A cold roof has the insulation placed below the structural deck which thus remains cold. When building a flat roof it is vital that a degree of falls is built into the construction to ensure rainwater run off.

These are can be supplied with rebated edges which interlock reducing the risk of uplift. The insulation material for a warm flat roof should. A warm roof has the insulation above the structural deck which is thus kept warm. Warm flat roofs do not need to be ventilated as the insulation is.

Insulation in a warm roof. The definition of a flat roof according to bs 6229 is having a pitch less than 10 o to the horizontal however some in the industry would consider up to 15 o as their definition of a flat roof. To achieve this add 100 to 160mm of insulation above the structural deck dependant upon insulant conductivity. Flat roof 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 insulation for a warm roof will usually be boards of extruded polystyrene or rigid compressed boards of glass fibre or rock fibre. The waterproof layer is above the insulation and a vapour control layer is placed below the insulation. Add to this the firring pieces for slope say 75 max. The typical u value of an existing uninsulated flat roof is 1 5w m2k.