Patent ID: 7829197

Claim:
A wall, ceiling or roof of a building comprising a film wherein the film is a monolithic membrane, is produced from a composition, and is permeable to vapor at 100% relative humidity; the composition comprises or is produced from one or more E/X/Y copolymers; one or more organic acids having fewer than 36 carbon atoms, or salts thereof; one or more alkali metal ions; and optionally one or more optional polymer; E is derived from ethylene, X is derived from at least one C 3 to C 8 , ethylenically unsaturated carboxylic acid, and Y is derived from a softening comonomer; the organic acid is optionally substituted with from one to three substituents independently selected from the group consisting of C 1 -C 8 alkyl group, OH group, and OR 1 group; each R 1 is independently C 1 -C 8 alkyl group, C 1 -C 6 alkoxyalkyl group, or COR 2 group; and each R 2 is independently H or C 1 -C 8 alkyl group; at least 60% acidic groups of the organic acid and the carboxylic acid is neutralized by the alkali metal ion; the alkali metal ion is selected from the group consisting of sodium ion, potassium ion, cesium ion, and a mixture containing at least 50% sodium ions and the balance being other alkali metal ions; and the film has a ratio of wet cup permeance to dry cup permeance greater than 10 when measured according to ASTM E 96-00 at a temperature of 73° F. (23° C.); the wet cup permeance is determined at an average relative humidity of 75% and the dry cup permeance is determined at an average relative humidity of 25%.