Method for improving the airtightness of buildings using a biopolymer-based membrane

Abstract

The invention relates to a method for improving the airtightness of a building or a room in a building comprising the application of a vapour barrier membrane to the inner face of the walls of said building or said room in a building, characterized in that the vapour barrier membrane is a hygroregulating membrane comprising an active part comprising - a middle layer with a thickness of between 2 µm and 200 µm, preferably between 4 µm and 100 µm, consisting of a biopolymer having a water vapour permeability coefficient P1 which increases with average relative humidity and which, when determined at 23°C and an average relative humidity of 25.5%, is at least equal to 600 Barrers, and, on either side of the middle layer and preferably in contact therewith, - two outer layers with a thickness of between 100 nm and 20 µm, preferably between 200 nm and 2.5 µm,consisting independently of one another of an organic polymer having a water vapor permeability coefficient P2, determined at 23°C and at an average relative humidity of 25.5%, of between 105 and 550 Barrers, preferably between 110 and 520 Barrers, in particular between 120 and 500 Barrers.,