The main difference between inverted roof systems and other roof systems is in the position of the waterproofing membrane. The ‘upside-down’ sequence means the deck is waterproofed first, then insulated and finally finished with paving or ballast. As a result, the waterproofing membrane is better protected from the elements and other factors such as UV radiation and rapid changes in temperature.
The waterproofing membrane is also less exposed to mechanical damage during the roof construction and from footfall and plant movement once the building is in use. Inverted roofs are therefore often specified for roof spaces that require plant or material storage and movement, as well as foot traffic.