Warm Roof System

What is a warm roof?

Warm roof construction is where rigid board insulation is placed over the roof deck and the waterproof membrane is laid over the insulation. 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.

Advantages and benefits

The advantages of warm roof construction:

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.

Warm roofs have significant benefits over cold roofs because:

energy efficiency is improved heating and ventilation costs are reduced.