Finish Balls Oozing Out Of Hardwood Floor


In early May we had our 40 year old oak floors refinished in our livingroom and diningroom. About two to three weeks later we noticed polyurathane balls developing at the board seams. I was upset……….They suggested that rather than starting over again we could remove the balls by scraping them off with a plastic scraper and wiping any residue left behind with mineral spirits if we did not want to get involved in refinishing again. We did. However, we noticed within a few weeks that more balls had developed. At that point we called the refinisher who told us that it was not their fault. They said that it was caused by dampness in our basement. My basement is not wet. I do run a dehumidifer ……….

Please separate fact from fiction. The refinisher never told me to run a dehumidifer. When new homes are constructed and hardwood floors are laid do they run dehumidifers in the basement before the new floors are finished…………


Dear Sandra What actually caused this was simply that they applied the last coat of poly over a first coat that wasn’t fully dry. Because this was an older floor, early on in the year, the gaps between the floorboards were probably still open because of the dryness of the winter indoor heated air. Then these gaps were filled with the first coat of finish. When more finish was applied over this, it in effect, encapsulated the first coat in the gaps. The gaps may have had old wax and junk in them that further interfered with the curing of this first coat. I always apply a very thin coat of poly, or thin it with naphtha on that primer coat.

Now as the summer humidity is expanding the wood, the gaps are closing and squeezing out the still wet polyurethane. And it surprising how many “little finish balls” will come out, and for how long. I’ve heard some cases where these little finish balls come out for as long as a year after the job was done. This was on a oily exotic wood, where a water based finish would have been a better idea.

You do have to remove the oozing balls as they occur, with a scraper, as has been suggested. But the floor guy should do this for you, or compensate you for the trouble. The fault, I’m sorry to say, lies at the feet of the contractor. He is considered to be the sole EXPERT in hardwood floor finishes. That has been the conclusion in all the small claims court cases where I have served as an expert witness. And if there was a need to de-humidify the basement (good idea) he would have had to specify this in the contract or at least tell you this before he started the job. I do always remember to tell my client to run the dehumidifier continuously before, during and after the job. Instead of employing the machine’s bucket, there is a hose attachment that will send the condensation down the drain.

Now I do tell folks this, and they will ignore me sometimes, so the blame can be shifted a bit in my case. But really, I don’t continue coating a floor that is still wet, just to stay on schedule. I can wait.

You might find that the compensation for removing the bubbles, and waiting for them to stop forming may cost as much if not more that the original contract. You might just ask for a return of all your money. Once a few summer months have gone by and no new balls are forming, then you can certainly “screen” and recoat the floor, and you should have a good looking finish. You should ventilate the floor with large industrial fans, just after the last bubbles have been removed and cleaned with thinner. Keep the house to about 70-75 F with the AC on and a few windows open just an inch. This all will speed the process. Probe the gaps with a toothpick to see if they have still soft finish in them. Wait and wait, don’t coat again over a soft uncured finish. Oh, and a full resanding may not help the situation at all, You cannot sand the inside of the gaps. It’s better to deal with the floor the way it is.

If you take the time to buy and read my lengthy article on “How to Apply Polyurethane with the Bubble” you will see that I wait out each and every coat of poly, till dry. And frankly I don’t do any work with oil modified poly when the weather is going to be hot and humid. Unless the house has AC. When this finish experiences temperatures over 80 F and 75% Relative Humidity, it starts to do strange things like you are experiencing. Any good floor finisher could buy and read this article, or contact his finish supplier. That’s why you hired these guys, for their specialized expertise. (or not)