Vapour Barrier For Cold Flat Roof

Bituminous vapour retarders asphalt mixed with felt or fiberglass or non bituminous vapour retarders plastic.

Vapour barrier for cold flat roof.

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. Vapour resistance of 2000 mns g. 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. It s the first line of defence against high vapour pressure air entering the roof structure and causing interstitial condensation.

Which ventilation solutions are available. In general the installation of a cold roof is not recommended for the construction of new properties. Self healing if punctured by fixings. Room in the roof constructions often use a combination of warm and cold roof constructions with varying types of insulation.

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. 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.

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. Most diagrams on the internet i have seen have plasterboard on joist insulation air gap osb board then roofing material. 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. Any advice would be great.

Temporarily waterproofs the roof can stay uncovered for up to 3 months. A vapour control layer or vcl on a warm flat roof sits between the roof decking and the insulation. Do i need a vapour barrier between the plasterboard and the bottom of the joist. Why is it the best vapour barrier for flat roofs.

Its not cheap purchasing it by the role and by the pallet load is cheaper but is a considerable layout. When the temperature of the vapour falls to or below its dew point the water vapour condenses on cold surfaces.