Mold- and moisture-resistant gypsum boards and methods for making them are disclosed, the method comprising applying a slurry that forms a gypsum core to an upper or a lower facing sheet impregnated with a thermoset resin (e.g., a phenol-formaldehyde resin) in an amount effective to (i) allow water vapor passage through the facing sheet when the thermoset resin is in its uncured state and (ii) provide mold and moisture resistance to the facing sheet when the thermoset resin is in its cured state and heating sufficiently to cure said resin and dry said gypsum core, thereby yielding said gypsum board.