Warm roof construction consists of a two-layer waterproofing membrane torch-applied over thermal insulation board and a vapour barrier. This means that the insulation is on the outside of the building envelope and the roof structure and ceiling space are at a similar temperature to the building interior.
The advantages of a warm roof:
- Thermal bridging is largely eliminated as the insulation is continuous over the whole roof structure.
- The need for roof space ventilation is eliminated or reduced. The ceiling space is on the warm side of the insulation. The dew point temperature (the temperature at which water vapour in the air condenses as water) is on the exterior side of the insulation, so condensation is unlikely to occur.
- Energy efficiency is improved
- Heating and ventilation costs are reduced.