What is a cold roof?

In a cold roof construction, the Sika-Trocal membrane is installed directly to the structural decking (usually timber). Then there must be ventilation between the deck and the insulation (traditionally a generic mineral wool) to prevent moisture vapour being transmitted from the building outwards where it could condensate in the roof construction  (interstitial condensation). 

Cold roofs are generally considered as ineffective for energy use reduction and building performance and providing for the ventilation is problematic.  Sika-Trocal membranes can be used in cold roofs but our advice will be to avoid designing them in the first place.

Please Note: This is not recommended practice (BS 6229:2018)

Image: Sika-Trocal Cold Roof System Build Up