Water-based or oil based polyurethane

Q: We have a 70-year old house with beautiful pine floors desperately in need of refinishing. So far we’ve had 3 professionals in to give us estimates. We have 2 large dogs so of course, durability is our primary concern and we’re aware that we need to trim and file their nails.

The first contractor recommended 3 coats of “high quality” water-based urethane with 1 coat of sealer underneath. The second contractor said 3 coats of oil-based polyurethane with no sealer under and the 3rd contractor said 1 coat of sealer under 2 coats of water-based urethane. We’re at a lost as to what to do and have 2 questions for you: 1) which is best for our situation: water-based or oil based polyurethane; and 2) do we need a sealer under the urethane?

A: High end water borne acrylic urethanes are quite tough finishes. Very expensive. I am still the old school guy. I prefer an oil base finish without sealers, of course. 3 coats, with each one buffed between coats. While water borne finishes (high end, such as Traffic, Mega, X-Terra, Dura Seal 2000 & Street Shoe) can present a tough film, they are generally lower in solids. Therefore, the finish build is not as great as with oil based. Especially for pine, I like that the oil based finishes will have time to penetrate into the soft surface. Water borne sets up so fast, there is little penetration into the wood at all.

I wouldn’t be too concerned about the sealer issues if you decide on water borne. Some of these products must have a sealer used first, but you should not need more than one sealer coat. I would definitely go with the 3 finish coat approach. If you go with the oil, sealers in my book are a real no-no, and spoil the durability of the finish. Even for occasional maintenance coats, oil based is easier to deal with down the road.