The present invention relates to, inter alia, methods for the treatment of wallboards with fungicides and the treated wallboards. In particular, the invention relates to the treatment of wallboards with synergistic combinations of an anilinopyrimidine fungicide and other fungicides. The invention also provides the treatment of building materials with synergistic mixtures containing an anilinopyrimidine fungicide. More specifically the anilinopyrimidine fungicide is cyprodinil.