In the case of wave slates the substitution of the old, obsolete, cracked or broken slates might cause a problem as this is a really complicated work and their transport is also costly. This way the roof might have leaks on it as well. The closed cell polyurethane foam offers a perfect solution for this as the old wave slate roof does not have to be removed but the foam can be spread directly on the surface to be insulated that eliminates all kinds of problems, for example the fixing points, small cracks or gaps.
By using the foam insulation, all leaks are terminated and also the dilation movements stop, furthermore the internal temperature changes are lowered to a minimum level as well. The foam insulation eliminates the condensation. It also strengthens the stability of the building, conserves it. Thanks to its light weight, it does not burden the roof structure.
In most cases a 3 cm thick sprayed polyurethane foam layer is sufficient for the optimal water-proofing. If the main goal is heat insulation then of course a thicker layer is required that is done with sprayed polyurethane foam with a density of 35 kg/m3. The weight of this foam is 1.8 kg/m2 if a 3 cm thick layer is used.