Provided are non-breathable films including specific polymer blends, and methods for making such films. The films comprise an anhydride and/or carboxylic acid functionalized ethylene/alpha-olefin interpolymer, a linear low density polyethylene, and an inorganic filler. The method of manufacturing the film comprises extruding an anhydride and/or carboxylic acid functionalized ethylene/alpha-olefin interpolymer, a linear low density polyethylene, and an inorganic filler to form the film and stretching the film. The films according to embodiments disclosed herein can exhibit low WVTR values and improved modulus while also incorporating significant amounts of inorganic filler at low gauges.