Vapor permeable liquid-applied membrane

A liquid composition for providing a vapor permeable air barrier membrane by spray coating onto a construction surface, comprising:

• an emulsion comprising at least one hydrophobic acrylic polymer having a repeating group represented by the formula —(CH2—CH(COOR)—)— wherein R represents a C2-C8 alkyl group, said at least one acrylic polymer having a glass transition temperature of −55° C. to 0° C. and being present in an amount no less than 50% and no greater than 97% by weight based on total solids in the composition;
• said liquid composition further comprising at least one inorganic filler selected from the group of calcium carbonate, talc, clay, silica, and titanium dioxide, said at least one inorganic filler being present in an amount of 5% to 30% by weight based on total solids in said liquid composition;
• the total amount of all inorganic filler contained within said liquid composition being present in an amount such that pigment volume concentration (PVC) is no greater than 16%;
• said liquid composition further comprising water in an amount no less than 30% and no greater than 50% by total weight of said liquid composition;
• and
• said liquid composition further comprising at least one water-soluble polymer being present in an amount no less than 5% and no greater than 17% by weight based on total solids in said liquid composition, and said at least one-water-soluble polymer having a solution viscosity, at 4% by weight in water, of no less than 2 centipoise and no greater than 50 centipoise.