Corotop Breathable Membranes form the water impermeable layer under the roof coverings in a pitched roof system. They can be used on open rafter (unsupported) or fully supported pitched roofs.
The function of the underlay is to isolate the building from water ingress that may penetrate the roof coverings such as wind driven rain. In addition, the low vapour resistance of the underlays can, when correctly incorporated into a designed roofing system, assist with the satisfactory management of water vapour within the roof system.
Corotop Breathable Membranes provide a barrier which:
Prevents the ingress of windblown rain, dust and snow
Has adequate strength to resist wind load
Offers resistance to tearing during installation
Remains flexible at low ambient temperatures
Facilitates the control of harmful surface and interstitial condensation
in the roof by allowing the safe dispersal of water vapour
Reduces heat loss caused by air movement through the attic space
once installed with no ventilation