Laminated composite material usable in heat-insulating composite walls

A laminated composite material particularly adapted for use as a fluid-tight primary or secondary barrieer in a heat-insulating composite wall in contact with a cold fluid such as liquified natural gas, methane, or the like, said laminated sheet material comprising four layers secured to each other for defining between themselves a pair of interfaces situated respectively between two of said layers, including a first end layer having a thickness of from 0.3 to 0.6 mm, a second end layer having a thickness of from 0.3 to 0.6 mm, a third intermediate layer, the latter intermediate layer being in the form of a flexible sheet material forming a fluid-impervious film, the thickness of which is from about 0.04 to 0.10 mm and material of which is selected from the group consisting of aluminum and stainless steel, each said first and second end layers being a flexible fabric made of glass fibers, and a fourth layer secured to said second end layer and having the construction of a coating applied originally in a finely divided state nd forming a continuous covering, said coating being selected from the group consisting of a polyurethane elastomer, a polychloroprene elastomer, and a chlorosulfonated polyethylene elastomer.