Cold Flat Roof Construction Ventilation

Cold roof voids are generally always required to be ventilated.

Cold flat roof construction ventilation.

In many cases cold roofs are used in storage spaces where there is no habitation occurring underneath. Cold deck flat roof the thickness of insulation required will vary depending on the material you decide to use and the manufacturer s specification. That means the rest of the roof is protected from heat. Why don t cold roofs need to be ventilated.

The ventilation system required for a cold flat roof must be installed during the construction of the roof itself. This significantly reduces the amount of rising heat and in turn condensation. However where vapour permeable or low resistance lr underlays are specified the levels required may be reduced. In a concrete deck for example this gap could be created by fixing 50x50mm timber battens at 600mm centres and attaching the insulation to underside of these battens.

The flat roof is finished in grp. A ventilation gap usually 50mm should be. The enclosed void of a warm pitched roof may not require to be ventilated but this is usually subject to the requirement to install a fully sealed air and vapour control layer avcl in conjunction with an air open roof covering. Ventilation for cold roofs.

Hopefully this video will help explain the difference between cold flat roof construction and warm flat roof construction this videos show detailed drawings. Their layer of insulation is beneath the roof decking and the roofing membranes. A cold roof really is colder than the rest of your home in the winter which means condensation is much less likely to develop. I have an outbuilding which has a cold flat roof construction.