Warm Deck Flat Roof Insulation Between Joists

Set the quinn therm qrfr ply insulation boards onto a wide 30mm bead of vapour resistant sealant applied to the upper surface of all the joists and cross noggins.

Warm deck flat roof insulation between joists. A warm flat roof is defined by insulation being installed on top of the roof deck. Alternatively battens can be secured to the underside of the joists and gmw fitted between these in much the same way as between the main roof joists. How to install insulation in a flat roof with timber deck insulated above the joists. Here the roof deck is maintained at the.

A cold flat roof is defined by insulation being installed between and if necessary underneath the timber joists. 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. No ventilation is required for these types of roofs. Cold deck roof with this type of roof the insulation is placed between the flat roof joists at ceiling level.

The underside of the rafters in this case will need to be finished with a suitable vapour control layer vcl and plasterboard to provide a suitable internal finish to the roof. Here the roof deck is maintained at the same temperature as the internal conditions hence warm deck roof. Warm deck the type of insulation for this is usually of a rigid type and the thickness will vary depending on the manufacturer s specifications. Warm deck insulation 1.

In the warm flat roof construction there is insulation packed into every possible space where air can flow. Good question theoretically when building a warm roof the vaper control layer goes on the warm side of the insulation. The major difference between the warm flat roof and the cold flat roof has to do with the air flow between the roofing timbers known as joists that help to hold up the roof. Cold deck this is where the insulation is placed between the joists rafters or in between the ceiling joists in the case of a pitch roof.

But as we are pushing head height our dormer meets the roof ridge right at ridge level so any vents and building regs seem to require a lot of them will be a little too exposed in my opinion. Cold deck roof a cold deck roof is where the insulation is placed between the joists rafters or in between the ceiling joists in the case of a pitch roof. Weatherproof covering eaves with ventilation gap 25mm continuous gap along two opposite sides weatherproof covering insulation decking and vapour barrier flat roof joists ceiling ceiling with vapour barrier insulation between flat. For this reason i would prefer to have insulation between the joists as with a cold flat roof construction.