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.

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. 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. Vapour control layers vcl. 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.

Time and time again i see the wrong vaper control layer being used and installed incorrectly. 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. 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. Vcls prevent excess moisture entering a wall s cavity behind the insulation.

The notion behind a vapour control layer is to install it on the room. Concrete slab flat roofs. Using a vapour control layer to control condensation the answer to keeping timber framed walls and roofs dry is to use a layer to restrict the flow of moisture but not to try and stop it. 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. If this has not been done then we would recommend that you install one underneath the joists before the plasterboard goes up. 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. The concrete deck can offer greater speed of roof construction which is an important consideration on many larger commercial projects.

Vapour control layer for a cold roof. Interstitial condensation can happen if warm air from inside th.