Warm Flat Roof Insulation Details

Insulation can either be put below the weather proof membrane which is called a warm roof deck construction or above the waterproof membrane which is called an inverted warm deck.

Warm flat roof insulation details. Insulating the roof above the rafters is known as warm roof insulation as the rafters are brought into the insulated envelope of the building. If insulation is installed below the flat roof deck this is called a cold roof. The waterproof layer is above the insulation and a vapour control layer is placed below the insulation. Flat roof u value 0 18 w m2k 2 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.

Eurothane eurodeck is a thermal insulation board for use in warm flat roofs under mechanically fixed single ply membrane waterproofing systems. A note to consider before construction. This enables the temperature of the structure and the deck to be kept close to the temperature of the inside of the building hence warm. The great thing about a warm roof is that if your existing roof surface is in good condition you don t need to do much to it.

A cold roof has the insulation placed below the structural deck which thus remains cold. The insulation is placed below the waterproof covering and is either mechanically fixed or bitumen bonded on to the top of the deck. This over rafter insulation method also reduces thermal bridging giving an airtight continuous layer of high performance insulation and results in a well insulated attic space. In creating the cold flat roof air is allowed to circulate freely between the joists and there is no insulation.

The sandwich warm deck roof is the most common type of flat roof. There are two basic categories of roof design. From there the flat roof system you choose will determine the materials you apply. Warm roof systems benefit from the insulation sitting above the deck.

A warm roof has the insulation above the structural deck which is thus kept warm. With a warm roof the insulation is installed on top of the existing surface rather than in between the rafters. In the warm flat roof construction there is insulation packed into every possible space where air can flow. The insulation is tapered to provide a fall to the roof to enable water to run to the water outlets.