Q: Our installer applied three coats of oil-based Duraseal and I would like an additional coat. Our installer did an awesome job but he thinks I am crazy to want another coat of polyurethane. How many coats of polyurethane for hardwood floors are correct?
I can see the small indentations in the finish where it has soaked into the grain of the wood. It is my experience that dirt collects in the grain and does not come out until the floors are refinished. It was quite an ordeal to refinish and install these floors and I would not like to do it again for as long as possible. In addition, we have 3 young boys and realistically they will be rough on the floors. What are the drawbacks to applying enough layers of finish until the surface is smooth?
A: I am with your installer at this point. I also typically apply 3 coats of oil-borne polyurethane. Oak is heavy grained, and that heavy sweeping grain is more open and will take in more of the finish. However, that does not mean there is no finish in that grain and that it will get dirty or absorb moisture.
Going beyond 3 initial coats may actually create curing issues and leave a tender finish for weeks to come. While most curing does occur during the first week after application, it does continue to cure over the course of the next few weeks. By continuing to build layers, you will retard the full cure process. I suspect that you will find the 3 coats you currently have will give you a few years of worry-free service, at least.
When the finish starts to look a little beaten up, THEN you can have it buffed, with perhaps 1 or 2 additional coats applied. I would strongly recommend against applying too many layers, one after the other. 3 is enough for now.
Is it possible to have too many coats of urethane?
Q imported from our old site, Face Lift Floors: Is it possible to have too many coats of oil-based urethane on a new hardwood floor? I have 6 coats on a floor and was told that it would peel and chip because of this. The contractors had a little difficulty with some dirt on the floor so they came back and polished then applied another coat. The total number of coats was 6. I would appreciate any input you have in this area as I am still under warranty for the floor and if it is going to cause a problem later I would like to know.
A: It could cause a problem if too many coats are applied without allowing previous coats to properly cure. Other than that, I don’t see 6 coats being a problem, if applied over time with proper buffing between coats. When the floors are buffed, a certain amount of the old finish is removed, and the amount removed depends on how aggressive the buffing is.
Original / moved link posted at https://faceliftfloors.com/q-and-a/xcoats.php