An aqueous based coating composition comprising a fatty amine quaternary having the structure of formula (I): R1R2R3R4N+X−； wherein R1, R2, R3, and R4 are independently selected from saturated or unsaturated, linear or branched, substituted or unsubstituted alkyl, aralkyl, or alkenyl groups comprising from 1 to 30 carbon atoms, whereby at least one of R1, R2, R3, and R4 is a C12-C30 group, and X−； is an anion from an inorganic or organic acid, is provided. The fatty amine quaternary may contain ethoxy and/or propoxy groups. One or more of R1, R2, R3, and R4 may be substituted and contain one or more hydroxyl substituents or ether linkages. Methods for imparting water resistance to a wood substrate having up to 100% moisture by applying a coating composition having the fatty amine quaternary of formula (I), and for preparing an aqueous coating composition comprising the fatty amine quaternary of formula (I) are provided. Also provided is a coated water resistant wood substrate comprising the fatty amine quaternary of formula (I).
