A method of finishing an interior wall includes the steps of preparing a substrate of building panels comprising gypsum, cement or combinations thereof, said substrate having a surface, followed by applying a coating to the substrate, said coating comprising 5-20% by weight of a latex emulsion binder, 40-80% by weight calcium sulfate hemihydrate, 0.05-2% by weight of a set preventer and 20-60% by weight water.