A coating method for gypsum board having a surface gypsum layer in which a polymer additive has been entrained including forming a gypsum board including the polymer additive entrained in a surface layer, application of a preferably acrylic primary coating, curing and drying the gypsum board, passing the gypsum board through a first roll coater wherein a second fluid coating is deposited over the primary layer of the dried, coated gypsum board in which the polymer additive has been entrained, the coating then being dried and cured, wherein the coating material of the primary coating forms a chemical bond with the polymer additive entrained in the surface layer of the gypsum board and the polymer of the primary coating forms a chemical bond with the second fluid coating. A coating material which can form copolymer bonds with the second coating is then deposited on the second coating and then dried and cured, resulting in coated gypsum board having a low surface tension surface that is essentially impermeable to water and vapor or moisture penetration.