Q: We have 2 large golden retrievers who have scratched the polyurethane finish on our hardwood floors. Should we sand all the way down or just part way? What is the hardest finish to use to minimize future damage?
A: If the wood itself has not become exposed and discoloured, or as I would call it “weathered”, you can lightly but thoroughly abrade the top coat of finish and apply another coating. Aluminum oxide finishes seem to be the norm in factory finished floors. They offer greater abrasion resistance, but will eventually break down and require recoating also. I know of one company that offers such a finish to be applied on site. Absolute Coatings. You may want to look them up.
The downside to such coatings is that they are so abrasion resistant that buffing and recoating is extremely difficult.