This is known as.
Vapour control barrier flat roof.
The vcl also restricts the movement of warm moist air and improves building insulation.
There is no requirement for any air gaps.
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.
Using a vapour control layer to control condensation.
Damplas vapour control layer vcl is intended for use within flat roof structures to prevent the penetration of moisture into structure surfaces and to improve the airtightness of buildings.
Including fibreglass roof kits torch on felt and liquid rubber products everything you need for flat roofing is in one place.
A polythene vapour barrier limits the movement of air and water vapour through a membrane so a vapour control layer is air permeable or vapour permeable.
Vapour control layers vcl.
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.
The vapour barrier is suitable for both warm and cold deck designs.
Comparatively a vapour barrier prevents any movement of vapour or air occurring through the building instead of just limiting it to a controlled level.
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.
Vapour control layer for a cold roof.
The notion behind a vapour control layer is to install it on the room.
We provide a vapour control layer for flat roof installations as well as heavy duty vapour control layers for a warm flat roof.
For all warm flat roofs a fully intact vapour barrier would be required on the room side under the insulation.
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.
A vapour control layer or vcl on a warm flat roof sits between the roof decking and the insulation.