Warm Flat Roof Construction

Yet for historic modern style buildings like this old house s cambridge tv project flat roofs are at the core of the architecture meant to reflect the broad horizontal lines of the natural landscape.

Warm flat roof construction.

As the single ply roofing association spra points out this type of flat roofing is strong durable completely sealed and usually lasts at least 25 30 years. The insulation is immediately below the waterproofing layer. Cold roofs and warm roofs. Due to the insulation being over the top of the roof the timber structure beneath is warm which is why the term warm roof is formed.

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. With a warm roof the insulation is installed on top of the existing surface rather than in between the rafters. For additional stability you can also use steel joists that are built into one or both of the walls. The vapour control layer is above the decking but below the insulation.

The insulation can be adhered mechanically fixed or loose laid. Steve from london flat roofingexplains how warm flat roof construction works in this excellent short video. Having a manual for warm flat roof construction with details and a summary of rules to follow helps. The basic construction of a flat roof starts with roofing timber that is laid across two upright items usually two walls.

Flat roofs aren t architecturally logical as rain and snow will shed much more quickly off a sloped roof. There are two types of flat roof. A warm flat roof is formed by placing a layer of insulation over the top of the roof structure. Flat roof construction can come in the form of a warm roof or cold roof depending on the requirement of the owner and architect as they relate to the building regulations regarding heat loss and insulation.

Warm roofs offer a superior thermal performance and therefore come with a higher cost. A warm deck roof is where the insulation is placed on top of the rafters joists and the roof covering is then placed over the insulation. From there the flat roof system you choose will determine the materials you apply. As opposed to old built up felt roofing with joins new single ply waterproof membranes are now most commonly used.

Of course you don t need to live in a modern house to deal with a flat roof. They can be built up from profiled metal decks as the insulation selected would provide enough rigidity to span the open sections of such decks.