Abstract: A multilayer membrane may be suitable for construction, and/ir adapted to be installed between a wall of a seat obtained in the ground and a concrete structure. The multilayer membrane may include: a first layer including thermoplastic polymeric material, impermeable or substantially impermeable to water; a second layer including thermoplastic polymeric material, impermeable or substantially impermeable to methane gas and/or radon gas and/or volatile organic compounds (VOC), fixed to the first layer and adapted to be positioned, when the membrane is installed, between the first layer and a concrete structure.

Abstract: The composite material multilayered membrane of the present invention is sound insulating and sound-absorbent, acting as sound deadening insulation for noise impacts, mainly but not exclusively to be used in flooring, and in particular under the slab in floating floors, with the aim of reducing the transmission of noise into the below room. This membrane includes several layers, which include at least one polymeric monofilament three dimensional mat, at least one resilient mat, and at least one topping layer of waterproofing, breathable or not, tissue. This multilayered membrane with a thickness under a weight of 2 kPa of at least 8 and maximum 15 mm, preferably 10-12 mm, so as to achieve a normalized noise level in the disturbed room Lnw below 50 dB, or an impact insulation class of at least 60 points.