Vapour Barrier For Cold Flat Roof

Room in the roof constructions often use a combination of warm and cold roof constructions with varying types of insulation.

Vapour barrier for cold flat roof.

Because of this the vcl always sits at the warm side of the. Any advice would be great. Vapour resistance of 2000 mns g. Do i need a vapour barrier between the plasterboard and the bottom of the joist.

Temporarily waterproofs the roof can stay uncovered for up to 3 months. For cold flat roofs the vapour layer needs to be positioned underneath the insulation layer on top of the room below to create an effective barrier. Why is it the best vapour barrier for flat roofs. The sloping ceiling areas include closed cell or foil backed rigid board insulants most of which are highly vapour resistant.

Which ventilation solutions are available. Cold roof areas usually include vapour open fibrous insulation e g mineral wool quilt. Flat roof vapour barrier materials when constructing a flat roof there are two types of materials commonly used. Self healing if punctured by fixings.

I am building a cold flat roof on an extension. A flat roof vapour barrier such as iko s mvp modified vapour protector offers appropriate moisture protection. In general the installation of a cold roof is not recommended for the construction of new properties. Most diagrams on the internet i have seen have plasterboard on joist insulation air gap osb board then roofing material.

Be it a cold or warm roof construction the primary function of a vcl is to keep warm moist air from inside the building inside the building. Bituminous vapour retarders asphalt mixed with felt or fiberglass or non bituminous vapour retarders plastic. It s the first line of defence against high vapour pressure air entering the roof structure and causing interstitial condensation. Its not cheap purchasing it by the role and by the pallet load is cheaper but is a considerable layout.

A vapour control layer or vcl on a warm flat roof sits between the roof decking and the insulation. A vapour control layer helps you shield your building from the consequences of condensation condensation is generated when warm moist air rises and condenses into a liquid on contact with the cooler areas above the insulation.