Warm roofs with traditional underlays and well-sealed ceilings
All warm roofs require a continuous vapour control layer (VCL) to be installed on the warm side of the insulation. The VCL should be lapped and sealed and all penetrations of the VCL, e.g. pipes, wires, etc., should be sealed to prevent moisture transfer into the insulation and the fabric of the roof structure. Even if a well-sealed ceiling is provided and the integrity of the VCL can be maintained, a ventilated air space should be provided above the insulation and the underside of the underlay.
The well-sealed ceiling will prevent the loss of heat due to conduction and thus provide an energy efficient solution.
The eave and ridge ventilation is provided for a 50 mm cavity above the insulation and below the underlay.
