Pitched Roof Air Gap

For more information on pitched roof insulation please see the kingspan kooltherm k7 pitched roof board brochure.

Pitched roof air gap.

The map at right which is based on table r806 4 of the irc lists the minimum r values required to prevent condensation in unvented assemblies in various climate zones. If 180mm is to be installed then 100mm board might be introduced between the rafters there has to be a minimum 25mm air gap between the insulation and the underside of. It is important that air is allowed to circulate between the roof covering and the insulation to avoid condensation a gap of at least 50mm 2 inch must be left between the insulation and the inside of the roof covering. For an unventilated roof without the use of counter battens a gap would need to be left for the breathable membrane to drape.

This gap must be ventilated at the top i e. At the ridge and also at the bottom either through vents at the eaves or. There will also be kooltherm k7 pitched roof board between the rafters image credit. Kingspan with a warm roof the usual process is to split the insulation into two layers.

An air gap in the rafters is not required as long as there is a channel for water drainage to run down the roof this can be achieved with counter battens that run vertically down the roof. An unvented roof assembly is possible only if you keep the roof sheathing warm enough to prevent conditioned air from condensing against it.