Cold Flat Roof Construction Ventilation

The flat roof is finished in grp.

Cold flat roof construction ventilation.

Why don t cold roofs need to be ventilated. Their layer of insulation is beneath the roof decking and the roofing membranes. However there is currently no ventilation and i am concerned that during the colder months warm air from the room below will rise up and meet with the colder air forming condensation and water droplets. 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. Hopefully this video will help explain the difference between cold flat roof construction and warm flat roof construction this videos show detailed drawings. However where vapour permeable or low resistance lr underlays are specified the levels required may be reduced. In many cases cold roofs are used in storage spaces where there is no habitation occurring underneath.

A ventilation gap usually 50mm should be. This significantly reduces the amount of rising heat and in turn condensation. The ventilation system required for a cold flat roof must be installed during the construction of the roof itself. This video shows the key features of a flat roof cold deck construction and how to draw the details to a scale of 1 10.

Ventilation for cold roofs. 2011 code of practice for control of condensation in buildings stipulates that there should be a ventilation gap between the insulation and the bottom of the flat roof deck of at least 50mm. Cold roof voids are generally always required to be ventilated. That means the rest of the roof is protected from heat.