floors can either be purchased as pre-finished planks or as planks that need to be sanded and finished in the home following installation. Manufacturers of pre-finished hardwood floors use varying materials for the finish, which usually include layers of polyurethane and aluminum oxide. The hardness of aluminum oxide can make these floors particularly difficult and costly to refinish, to the extent that most engineered wood floors do not get refinished, even if they can be.

Hardwood floors can be repaired by spot-sanding and refinishing,