Flat Roofing Warm Flat Roof Fascia Detail

A vapour control layer must be used below the insulation.

Flat roofing warm flat roof fascia detail.

Single ply membranes are also used but are particularly suitable for larger roofs. A warm flat roof is formed by placing a layer of insulation over the top of the roof structure. Underneath the basics flat roofs are usually constructed with a ceiling nailed to joists which support a deck usually wood in residential construction a vapor barrier insulation and a roof board. From there the flat roof system you choose will determine the materials you apply.

If you put insulation under the decking and between the joists you lower the temperature of the decking and lower the due point thus bringing it closer to the danger point of being in the building. This approach uses insulation with no air gap either immediately above or below the roof deck. The basic construction of a flat roof starts with roofing timber that is laid across two upright items usually two walls. Cad details document name pdf dwg download all cad construction details 37 1 mb 3 4 mb mc01 identification of roof areas 694 kb 167 kb mc01a single layer underlayment 678 kb 302 kb mc01b double layer underlayment 711 kb 322 kb mc02 vent pipe flashing 626 kb 349 kb mc03 valley.

Flat roof joists spanning the shorter length of the roof form the load bearing members of the structure. Steve from london flat roofingexplains how warm flat roof construction works in this excellent short video. This option avoids the requirement to ventilate the roof. This is where the insulation is typically packed between the rafters.

Good question theoretically when building a warm roof the vaper control layer goes on the warm side of the insulation. Traditionally domestic flat roofs use two or more built up layers of bituminous felt as their weather proofing. The roofs have a timber frame as the supporting structure. In this video our principal surveyor steven dickinson explains problems with insulating a roof using the warm and cold roof construction methods.

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. Front fascia flat roof detail. A timber decking is then constructed and its weight supported by the joists. For additional stability you can also use steel joists that are built into one or both of the walls.

If the specification of the insulation is not correct you could have problems. Having a manual for warm flat roof construction with details and a summary of rules to follow helps. Liquid applied systems such as glass fibre were introduced and are now quite widely used.