I am refinishing my 50+ year old hardwood floors. Quartersawn oak and the previous owner’s pet, probably a cat, caused stains in several areas around perimeter of a couple of rooms. I have used a drum sander to remove the old finish down to bare wood but the pet stains are still visible.
I’ve heard of wood bleach. Will that work, and if so, do I get it at wood flooring supply stores and/or Lowe’s? Or, do I have to hope the wood stain I use (Minwax Provincial) will cover it and blend with the rest of the floor?
Replies
You can try the bleach but I would spend the extra money and weave in some new quarter sawn oak. A professional job will be invisible even with a clear finish.
Any chance that you could post a pic of the stains?
I could probably post a picture of the floor and stains. But, I was wanting to finish the floors this weekend. I may test a small spot where the floor stain will be applied over the pet stain and non-stained wood and see what result I get. Just curious, how will seeing a picture of the stain affect the advice you give?
Can't reply in depth right now as my FIL was admitted to the hospital this morning and we've gotta head up there right now. I'll intend to get back to you on my return later tonight.
Knowledge is power, but only if applied in a timely fashion.
I don't see how you can "match" a fifty year old quartersawn hardwood floor with new. If there aren't that many affected areas and you have enough material that can be ripped out of a bedroom or some closets for example, use that in the more visible areas and replace with new in the removed areas. That's the only sure method the way I see it, if you're seeking a floor that doesn't look repaired.
Ken Fisher
http://www.hardwoodinstaller.com/hardwoodinstaller/meet.htm
O,
I was curious to see the stains as it would effect what I might suggest in the way of bleach.........oxalic acid crystals or two step peroxide.
From the sounds of the stains you described now, I'd probably move right to the two step peroxide. This stuff requires vigilance (and substantial experience doesn't hurt) if you're going to "shut it off" with some vinegar at the right time and not end up with a result that is lighter than the rest of the floor.
Sounds now like the point may well be moot if you're intending to apply finish this weekend. I won't bore you with the procedure unnecessarily unless you're prepared to put off finishing for a day while you try to carefully coax the wood back to the appropriate color. If you do decide to give this a try, let me know and I'll try to describe what you need to do to achieve a successful outcome.
Knowledge is power, but only if applied in a timely fashion.
I've used muriatic acid on pet stains on wood and concrete floors. I was told that the acid permanently damages the wood but never found any evidence of it myself.
I showed this to an experienced floor guy and he was amazed at the results. I don't know how/if it worked for him thougj.
Eric
I didn't get around to finishing the floor this weekend; I went ahead and painted the walls and ceiling of the rooms. If the processes you've described require a ton of work, I may go ahead with my plan to stain the floor and see what happens. You mentioned at least one of the processes requires experience with the procedure, which I don't have, obviously. If you don't mind, set out the procedures you must follow to use the process which requires the least amount of know-how. Is it possible that the stains have lightened some since I sanded the floors to bare wood? They appear to have lightened. Thanks.
To check how apparent the stains will be when the finish is applied, wipe the area with a damp cloth --- usually they come up really black.You can forget about sanding them out because the 'stain' is caused by a chemical reaction between the urine and the tannic acid in the oak and the dark discoloration will go right into (sometimes clear through) the timber.I've used repeated light applications of oxalic acid and removed them in the past but it's a time-consuming exercise.Staining the whole floor darker isn't a complete cure either, the urine stains will still show as darker patches.I'd try bleaching with oxalic acid first and if that isn't satisfactory, either replace the affected boards or live with it.IanDG
O,
The first thing you'll need to do in this attempt to remove the stains is to make a run to the hardware store and buy some 2 step peroxide wood bleach. This will consist of two bottles of liquid in a box. It's the chemical interaction of the two that causes the bleaching, so you can either apply "solution A" to the wood first and then follow up right away by applying "solution B". If you do this, use separate small brushes for each solution and don't get them mixed up. Or you can mix equal portions of the two together in a separate glass or small plastic container and apply this mixture (this is what I usually do. Only mix a small amount (say a couple of tablespoons or so) together at first if you choose this approach, as any you don't use in relatively short order will be exhausted and useless. (You should see some foaming action from this mixture when mixed and/or applied. If you don't and you don't see any bleaching result, then it probably means that the solutions are past their shelf life. I'd take them back and get a set with an expiration date on the box that's still current.)
You'll also need a bottle of vinegar as a neutralizer.
I think you'll want to be using some small cheapy artist's brushes for this job, but since you know the size of the stains, you'll have to decide what's appropriate. It's control of the bleach solution around the very perimeter of the stains that's really important, as you don't want the stuff getting on the unstained wood and that perimeter is where any evidence of difference in color will be most apparent. The small artist's brushes are a must IMO around those edges.
Now for the unknowns. Since I can't assess the stains from here, it's impossible for me to say whether this will remove the stains and/or what the necessary amount of bleaching time is. This may vary from one area to another. The important thing to remember is that this stuff is a much more powerful bleaching agent than oxalic acid and can bleach walnut nearly as white as snow if applied about three or four times and allowed to run it's full course and then dry out each time.
On that note, I'd recommend that for your first application, you only allow it to work for five minutes and then neutralize it with a bit of vinegar wiped on the surface. You should then allow the wood to completely dry out to see what the result truly is. If the wood is still damp, you likely haven't seen the entirety of the result. You could speed things up by force drying the area with a fan.
Be certain the wood is once again dry and then judging from the results of the first application, try to judge how long it would be safe to let it work on the next application. This is where it's easy to get fooled so error on the side of short rather than long until you're pretty sure about what you're doing. Sight unseen, I probably wouldn't go more than ten or fifteen minutes on the second application. Frequently enough, getting a matching color or the best obtainable result in the end is a matter of a minute one way or the other. Don't forget to neutralize.
Now you can judge from the first two applications what might be required to get where you're headed. Some areas may well require more applications and bleaching time than others. Your stains may be so dark or so resistant that you'll find yourself allowing the solution to run full course, dry out on it's own and still have to apply more. You might also find that you needn't totally remove the offending stains to get your wood stain to cover the remainder of it and blend with the rest of the surrounding wood.
A word of warning: I've coached other people about this procedure and sometimes they end up with the area too light because they went to the kitchen for a cup of coffee and lost track of time.
Knowledge is power, but only if applied in a timely fashion.
"O"
How dark are the stains? Did you screen after the big machine sanding? Letting the big spinner rest for a second or so on the stains may reduce them some. I would apply the provincial stain lighter on the pet stains and wipe it off sooner than the rest of the floor. Bleach rarely works very well. As mentioned, the only sure way to eliminate the stains is to "key" new boards in the floor.
Ditch
Stains aren't very dark, sort of chocolate colored. I did not screen the floors after going over them w/ 100 grit paper on the drum sander - I have to match the living room floor I refinished last year (it was my first attempt at refinishing and it looks good, but I didn't screen after using the drum sander on it). That raises another question: The current job meets the living room floor in a 30 inch doorway. How do I blend the polyurethane? I plan on going into the living room about 6 inches and tape off after that point. Then, I'll use a polyurethane stripper (liquid) inside the tape and when I finish the new job, I'll put polyurethane onto the 6 in strip too. Do you know if this will work?
I was on a job a couple of years ago that had the same problem. The floor man worked with sanders and bleaches but finally had to give up. His recommendation was to stain the whole floor the color of the stains. Personally, I would go the extra cost of replacing the wood.
I ran into that exact problem last year, only the pet stains were 20-25 years old. I ended up replacing oak almost everywhere the stains were dark. It was recommended to me to use a product called Nature's Miracle, available at pet stores. It's actually an enzyme that digests the protein from any bodily fluids. Supposedly it eliminates odors, too. It didn't work very well for me, probably because of the age of the stains, but I was told that even if you get rid of a stain with bleach or sanding, the dog will still be able to smell the area, and will lay down a fresh coat of urine. If the stains aren't that old, I would definitely give it a shot. Good luck.
Brian
What is the condition of the floor? When we were looking at houses two years ago, we encountered several 1920-1940 houses which had just had new hardwood floors installed, and boy did they look out of place. Keeping that in mind, we had the first floor oak in our house sanded and refinished with full knowledge that several stains would likely remain. Not sure if they were due to animal or repeated plant watering, but their presence is in character with the age of the house. And if we do hardwoods in the kitchen renovation, I may even look into getting salavaged wood for that period look. Just a thought.
Thanks to all for the suggestions, advice, cautions, etc. I may try the oxalic acid bleaching Goldhiller described, but only after I stain a small area of the floor to see what it looks like. The reason I'm reluctant to go to the hardware store right now and get the materials for the bleaching is because the previous owner's pet(s) stained a large number of boards covering a large area - along 3 or 4 10-14 ft walls continuously about 1-2 ft out from the wall.
Oh my.........if you've got that large of an area to do, I think you'd best acquiesce to replacing the lumber.
Didn't these folks ever turn their livestock out to make diddle?
Maybe this is your chance to do a contrasting wood border around the room. No matching required.
Knowledge is power, but only if applied in a timely fashion.
Here's a suggestion -- why not adopt a Victorian style and stain an 18" border all around the perimeter of each room the same color as you'll use for the main floor but as dark as you can get it.IanDG
As widespread as the stains are, maybe the previous owner's relieved themselves on the floors? Anyway, the problem with making a border around the perimeter of the rooms is that it wouldn't match the 2 rooms I refinished last year when I moved into the house (there is no border in those rooms). I only had time to refinish the living room and dining room floors (really one, big room), and there were no stains at all in those rooms. When I ripped up the carpet from the floors I'm now refinishing, I got the shock of seeing the pet stains. Apparently, I have no hope of matching the finish over pet-stained areas and non-stained areas, judging from the posts. I'll take all the suggestions and try to figure out something.
We suspect the residents (owners) of a house in my old neighborhood did this. A guy bought it for for about 50% market price because of the run down condition, but I think we were all shocked at how bad it was. They had a dozen cats, but it seems as if the humans contributed as well. Even after 6 months of airing out with the windows open and all the flooring and walls removed in the bathroom and kitchen, it was still hard to be in the house for more than 15 minutes. After a year of airing he finally ended up painting in the smell on the third floor joists. I am so glad we never had a chance to make an offer on the place.
Keep in mind that your stains are exactly the same as if you'd fumed the oak. The colour penetrates very deep even after a few hours in ammonia and you've got the result of a few (up to 50) years. Powerfull bleach/oxalic acid is the only way to go from what I've read though never tried. Breaking down animal enzymes is way too late. Staining to match a fumed finish would be nearly impossible IMHO.