An inverted roof is basically a single-leaf, unventilated flat or shallow-pitched roof, in which, contrary to (or in an inversion of – hence its name) the “normal flat roof” the thermal insulation lies on top of the waterproofing and is exposed to the elements. In this case, the thermal insulation protects the waterproofing rather than the waterproofing protecting the thermal insulation.
Various superstructures can be installed on the thermal insulation, leading to inverted roofs suited for different purposes. However, the basic concept remains the same; the thermal insulation is always laid on top of the waterproofing. Inverted roofs can be used for a wide range of applications, including extensive or intensive roof greening, gravel cover, or load bearing, either as a terraced roof or as a parking deck. This illustrates the range of requirements that the thermal insulation material must be able to meet. XPS is the material of choice for inverted roof insulation applications due to its:
- Outstanding water resistance.
- Excellent dimensional stability.
- Exceptional load capacity.