Vapour Control Layer Concrete Flat Roof

A vapour control layer or vcl on a warm flat roof sits between the roof decking and the insulation.

Vapour control layer concrete flat roof. Interstitial condensation can happen if warm air from inside th. Including fibreglass roof kits torch on felt and liquid rubber products everything you need for flat roofing is in one place. In this case you need to lay a full vapour barrier on top of your flat roof deck before you lay the insulation and your flat roof covering. Vcls prevent excess moisture entering a wall s cavity behind 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. The roof should incorporate insulation and usually a vapour control layer to protect from interstitial condensation. Vapour control layers vcl. A vapour control layer or vcl for short is a plastic layer that restricts the movement of warm moist air from inside a property into the fabric of the building.

A concrete slab flat roof is normally made up of a structural layer of concrete finished with a smooth screed onto which a water proof layer such as a membrane is laid. If this has not been done then we would recommend that you install one underneath the joists before the plasterboard goes up. At roofing superstore our choice of flat roof materials includes everything you need to create a long lasting weather proof flat roof that performs and looks good too. The notion behind a vapour control layer is to install it on the room.

However the cross ventilation does not completely remove the moisture vapour in the ceiling void and a vapour control layer sealed at joints and penetrations is required under the insulation and over the plasterboard to provide a barrier against moisture vapour rising up from the room below. To insulate a flat roof with a concrete deck we recommend a warm deck construction method where the vapour control layer is sandwiched between the concrete deck and a layer of rigid pir insulation boards. Vapour control layer for a cold roof. Concrete slab flat roofs.

With any warm flat roof detail such as this a vapour control layer should have been laid on top of the roof deck underneath the insulation. The vapour control layer vcl often overlooked underrated punctured adlib and sometimes even completely omitted mainly because we re just not sure if it really is all it s cracked up to be after all even if we leave it out altogether the roof shouldn t leak right.