we are experiencing stain/finish on the surface of our finished wood flooring several weeks/months after they are coated. We suspect that the cause is trapped wet stain/finish that migrates to the surface with the assistance of floor movement and/or moisture migration. Has anyone else experienced or encountered this problem?

Thanks,
Brad

What species of wood, and what finish?


Is it squeezing finish from the edge gaps?

Various species of wood, but mostly on oak. It doesn't seem to matter of the width. We have found the problem to be more consistent with darker colors or waterpopped floors.

I have even had one of my maple gym floors experience the same issue. It was installed/ sanded and finished 12/05-1/06 (yes, all moisture related issues were followed concerning acclimation, CC test, environment controls, etc). It was fine until we recoated during spring break, a few weeks later these poly balls appeared. From examination, it is determined that they are from below the surface because they are below ALL coats of finish (except for sealer coat).

I have been told that Bona Prep lessons or corrects this issue, but I have had no reply from Bona yet. I am just wondering if this is happening elswere?

B

Are these coming through the joints/seams between the boards? If so, the answer is simple. The finish seeped down into the seams/joints and wasn't completely dry before another coat was applied over it. As the floor expands, it pushes the not dry finish to the surface, where it does dry, forming poly beads. It usually happens more with OMU because OMU takes much longer to dry than waterbornes do. I have had this happen to me and it's a pain. The only thing you can do is either use water based finishes and make sure they are absolutely dry before coating again and follow manufacturer's directions on spread rate and dry times. Another issue in coating floors is one must control the temperature and humidity. I recall two floors where I didn't do this and both of those jobs came back to haunt me. After staining, the temps got high and dry and the wood shrank. I coated them anyway. Then the floors went back to normal as the temps returned to normal and guess what, poly beads Also, use a faster drying OMU if you use one. Some brands, like DuraSeal, are much slower drying and are very thin in consistency and tend to seep between the boards more readily than some other brands, like Woodline.

Most of the floors that this has occured on have been within controlled atmospheres. I would agree with your assessment of the situation and cause. However, we are allowing (what should be) adequate dry time between coats. When we inspect the flooring 24 hours after previous coat, we see no reason not to apply the second coat. We are using Dura Seal stains (fast dry) and first coat of finish is Dura Seal Masterline (which is a quick(er) drying OMU. Final coat is Polo Plaz OMU. We have even had 1-2 jobs where they were coated with waterborne (traffic) and still had polybeads! The gymnasium was dormant for 3 months prior to experienceing the issue- but during that three months, we experienced normal variations in weather/climate changes, heavy traffic on the gym, variable within the humidity/moisture inside the gym, etc. I would have expected the issue to arise sooner. I had the Dura Seal rep examine the floor and he was as suprised that the first coats of finish were not dry after such a long period of time. ??!!???!!??

So, what is the answer? Longer periods between coats? How do we determine what is long enough- when we can't see or test the cracks between the flooring planks?

IMO, if a product isn't working out for me, I switch products. Even though that Dura Seal 1st coat product is a fast dry, if the consistency is thin, it will still seep into the joints between the boards and not dry. Personally, I gave up on Dura Seal years ago. Too many problems with their products. I am pretty much a user of Bona finishes. When using an OMU, I use Woodline and rarely have problems. This is a heavier bodied finish but still applies nicely and always dries reliably. And it is durable. I use Bona waterbornes as well, Traffic or Strong with either Bona stain or Bona Seal. I never have the problems with poly beads now. In fact, the two times I did, I used Dura Seal. So that ought to tell you something. I'll use Basic's finishes occasionally; Emulsion and Street Shoe but Traffic is more durable than Street Shoe. I have heard good things about Polo Plaz but since it's not distributed here, I haven't had a chance to use it. Besides, I think your problem is the Dura Seal. Eliminate that and I think you'll find your problems will be gone.