Sealing sheet assembly for construction surfaces and methods of making and applying same

A multi-layer unit for bonding onto a surface of a construction and thereby sealing the surface of the construction comprising:

• (a) an upper sealing flexible layer having at least it's outer part protected against chemical and physical environmental influence;
• and
• (b) a lower layer bonded to said upper layer, said lower layer being elastic, closed cell, foamed polymeric material having a module of elasticity significantly lower than that of the upper layer and having tensile strength significantly lower than that of said upper layer, said material having an elongation at break of at least 25% in a designated temperature range, and a gas volume in a range of 65% to 99% of it's total volume;
• wherein if said upper layer is thermoplastic or thermosetic, and further wherein if said lower layer has a thickness of above about 2 mm, or if said upper layer is of bitumen, then, said upper and lower layers are selected such that if said tensile strength of said upper layer, according to it's definition in ASTM Standard D-751, method A, is expressed in units of Newton per 50 mm width, and said tensile strength of said lower layer, according to it's definition in Din Standard 53571, is expressed in units of Newton per 1 mm squared, then, the ratio between said tensile strength of said upper layer and said tensile strength of said lower layer is greater than 200, whereas, if said upper layer is thermoplastic or thermosetic, and further wherein if said lower layer has a thickness of below about 2 mm, then, said lower and upper layers are selected such that a ratio of said tensile strengths of said upper and lower layers, when expressed in said units, respectively, is greater than 1000.

A multi-layer unit for bonding onto a surface of a construction and thereby sealing the surface of the construction comprising:

• (a) an upper sealing flexible layer having at least it's outer part protected against chemical and physical environmental influence;
• and
• (b) a lower layer boned to said upper layer, said lower layer being flexible plastic, closed cell, foamed polymeric material having tensile and shear strengths significantly lower than that of said upper layer, said material having a gas volume in a range of 65% to 99% of it's total volume;
• wherein if said upper layer is thermoplastic or thermosetic, and further wherein if said lower layer has a thickness of above about 2 mm, or if said upper layer is of bitumen, then, said upper and lower layers are selected such that if said tensile strength of said upper layer, according to it's definition in ASTM Standard D-751, method A, is expressed in units of Newton per 50 mm width, and said tensile strength of said lower layer, according to it's definition in Din Standard 53571, is expressed in units of Newton per 1 mm squared, then, the ratio between said tensile strength of said upper layer and said tensile strength of said lower layer is greater than 200, whereas, if said upper layer is thermoplastic or thermosetic, and further wherein if said lower layer has a thickness of below about 2 mm, then, said lower and upper layers are selected such that a ratio of said tensile strengths of said upper and lower layers, when expressed in said units, respectively, is greater than 1000.

A multi-layer unit for bonding onto a surface of a construction and thereby sealing the surface of the construction comprising:

• (a) an upper sealing flexible layer having at least it's outer part protected against chemical and physical environmental influence;
• and
• (b) a lower layer bonded to said upper layer, said lower layer being elastic, closed cell, foamed polymeric material;
• wherein bonding said upper and lower layers is effected by an adhesive or welding, such that non-bonded closed cells are formed between said upper and lower layers.