A roof with waterproofing that is applied directly on the thermal insulation, without an intermediary air layer. The roof support is protected from big changes in temperature by the insulating material and is therefore not subject to small-scale thermal shocks. On the other hand, the waterproof membranes are directly subject to the effects of the climate (temperature changes, the UV rays of the sun, etc.).

We protect against these climatic effects by placing ballast (strong protection such as gravel, slabs, etc.) onto the waterproofing material.