Under the insulated floor on the ground, first a lean concrete base with a thickness should be made 10-15 cm. On such a base, we can only lay a waterproofing made of two layers of tar paper or construction foil glued with mastic. It is only on the waterproofing layer that thermal insulation made of polystyrene or mineral wool is laid. On the mineral wool insulation, a layer of tar paper or foil should also be laid to prevent the penetration of mixing water from the concrete screed..
