Enzyme residue from urine stain discoloring floor

Q: We just had our floor refinished with a dark walnut stain and 3 coats of semi gloss polyurethane. My dog unfortunately found that to his liking and urinated on the surface. We immediately wiped it up with a wet paper towel but the surface around that spot has now turned grey and is very noticeably different from the rest of the floor.

How do we fix this? The poly was only down for 24 hours.

A: I’ve never heard of this sort of thing. You wiped it up immediately with paper towels but there is still residue on the surface. Did your floor guy provide you any proper cleaner for polyurethane finishes? If yes, I would wipe the area with that to see if it helps. If not try some alcohol. Was this a water borne finish? It was so fresh, I hope the uric acid did not etch into the finish itself. I find it near impossible to believe this is a reaction of the stain. So it is with/in the finish. You might have to try a spot touch up with finish or recoat the room.

Follow-up: Thanks so much for your quick reply, it’s a water based semigloss polyurethane and its 3rd coat was down less than 24 hours before this happened. It was dry enough to walk on so we were shocked with the result as well. The installer did not give us a proper cleaner so what would you recommend and do you think sanding the area with some fine steel wool prior to any application would help take the grayness out of the finish first? And as far as alcohol what type do you recommend.

A: There are many floor cleaners and any local hardwood retail outlet should have a version of it. Companies such as Bona, Poloplaz, Basic Coatings, Dura Seal, Min Wax etc all make cleaners that generally contain a small amount of ethyl glycol. You should be able to find a cleaner in any hardwood department. Just stay away from supermarket cleaners such as oil soap, pine, etc.

Don’t go near a water base coating with steel wool. I would use fine sandpaper, 120 grit or finer. There is also another product I’ve heard of which is designed to remove urine and for the life of me I can’t recall the name.

It almost looks like it has cut through the finish and is pushing it off the floor. I would wipe it down with a cleaner then rub it down and try another coat. That is nasty and hard to believe this is not a result of a long term favorite spot of your dog.

Follow-up: We bought the Bona and applied it to the area in question. It improved it greatly. Tried a couple more applications and got most of the grayness out. I purchased a dark walnut Minwax pen and used it in between the boards where the spray could not reach and that seems to have resolved the issue. Thanks for your assistance.

A: That is fantastic to hear. So perhaps there was residue of enzymes and other gunk from the urine on the floor, causing this discolouration.

Related Q: My dog had puppies and they left little discolorations on the floors. Would you suggest replacing boards and refinishing the floors or maybe a spot treatment? Any recommendation for a thick finish that might prevent this sort of staining, e.g. a gym floor type finish?

A: I assume you mean urine stains. It’s a tough one. Ultimately the puppies should be confined until they have some bladder control and training or wiping up accidents promptly.

I have heard of hydrogen peroxide being used with some success in stain removal. There is also another product I’m interested in which is called stain solver. www.stainsolver.com

I did a test on several boards years ago where a good size puddle of water was placed on top of oak strips I had stained and finished with Poloplaz Primero. The water did not penetrate through the finish in 24 hours. Of course, uric acid may be another animal all together. I’ve not tested that. But a thicker finish can’t be an answer and would likely present it’s own issues. Polyurethanes are best applied in thin coats, perhaps 2-3 applications. I would try the stain solver. You mix a bit of paste and place it on a spot. See if it removes it. If not the floors will have to be sanded to clean wood. If the marks don’t come out try the paste again. If that doesn’t work you may have to remove the boards.

Follow-up: I have them contained but try to allow the bitch access to them. This in turn means an escaped pup or two, being that I am currently working split shifts and can’t watch them as much as really needed. Thanks for your advice!

Follow up question.. would it be possible to use a heavy urethane to fill approx 1cm cracks between the boards? I understand this is pretty normal, but a “sheet of glass” would look pretty cool.

A: Those are large gaps. There is no shortage of various wood fillers and adhesives on the market to fill gaps. I’d do a search and use one of those. Don’t use silicone caulking though.

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