Vapour Barrier For Cold Flat Roof

It s the first line of defence against high vapour pressure air entering the roof structure and causing interstitial condensation.

Vapour barrier for cold flat roof.

Bituminous vapour retarders asphalt mixed with felt or fiberglass or non bituminous vapour retarders plastic. Room in the roof constructions often use a combination of warm and cold roof constructions with varying types of insulation. Temporarily waterproofs the roof can stay uncovered for up to 3 months. Cold roof areas usually include vapour open fibrous insulation e g mineral wool quilt.

Vapour resistance of 2000 mns g. The notion behind a vapour control layer is to install it on the room. Any advice would be great. Do i need a vapour barrier between the plasterboard and the bottom of the joist.

Because of this the vcl always sits at the warm side of the. 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. Which ventilation solutions are available. A flat roof vapour barrier such as iko s mvp modified vapour protector offers appropriate moisture protection.

I am building a cold flat roof on an extension. Its not cheap purchasing it by the role and by the pallet load is cheaper but is a considerable layout. 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. Condensation within a flat roof mainly occurs during cold weather when moisture vapour in the air which has been generated within the heated building rises from the room below into the cold roof void above the ceiling.

A vapour control layer or vcl on a warm flat roof sits between the roof decking and the insulation. Flat roof vapour barrier materials when constructing a flat roof there are two types of materials commonly used. Why is it the best vapour barrier for flat roofs. Self healing if punctured by fixings.

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. The sloping ceiling areas include closed cell or foil backed rigid board insulants most of which are highly vapour resistant.