Crosslinkable aqueous-based coating compositions are described which are covalently bonded to a wooden surface to which they are applied. The compositions contain a crosslinkable polymer, a mono and/or polyethylenically unsaturated monomer which can be graft polymerized onto cellulose molecules present in said wooden surface, a water soluble peroxy free radical polymerization catalyst, a source of cations capable of creating free radical sites in said cellulose molecules and, optionally, a crosslinking agent for said crosslinkable polymer. The coating may be air dried under ambient conditions to provide a crosslinked coating which is chemically bonded to the underlying wooden surface.