Cold Deck Roof Detail

Throughout the course of the year the roof deck and all below it is kept at a temperature close to that of the inside of the building therefore the roof structure is protected from extremes of hot and cold lessening the potential for.

Cold deck roof detail. 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. A warm flat roof or a built up roof bur is one where all the insulation is above the joists deck making them part of the warm fabric of the building. The insulation can be adhered mechanically fixed or loose laid. This is known as a cold roof because the roof deck and roof space are close to the external air temperature.

This temperature criteria can be reduced to 40 f which corresponds to interior average conditions of 70 f 35 rh where high interior moisture loads due to spas indoor swimming pools and excessive humidification are. Warm cold and inverted. The vapour control layer is above the decking but below the insulation. In a warm roof construction the principal thermal insulation layer is located above the structural decking resulting in the structural deck and support structure being at a temperature close to that of the interior of the building.

In a warm deck roof the insulation is positioned above the structural deck and no ventilation is required. There are three recognised designs of flat roof construction. In a cold roof construction the sarnafil membrane is installed directly to the structural decking usually timber with firrings to fall. The epdm rubber roof membrane is then installed using the contact adhesive onto the deck.

The 18mm roof grade deck is then fixed on top of the rafters leaving suitable air flow between the insulation and the deck. In cold and very cold climates selecting a roof deck condensing surface temperature criteria of 45 f is very conservative. Ventilation is required for these roofs. There must be an adequate void minimum 50mm between the deck and the insulation traditionally mineral wool to allow free movement of air and to prevent moisture vapour being transmitted from the building outwards where it could condensate in the roof.

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. The insulation is immediately below the waterproofing layer.