Pet Urine Stains on Sub-flooring

When replacing flooring you may find problems with the sub-floor. This guide is about pet urine stains on sub-flooring.

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I'm replacing carpet in livingroom that a dog has gone to the bathroom on. How do I seal the subfloor so the urine smell doesn't come through?

By Betty from Hastings, MN

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We just went through this! My husband used shellac. He applied it 4 times with it drying in between applications. This was recommend to us by our carpet installer. It worked great!

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The product I have used on sub-floors is called Killz. It is not too expensive and one gallon will go a long way. One thing to remember though, it is not "paint", in other words, it is not necessary to have a good coat on. See through is fine as long as it is applied evenly over all affected areas. it will work on walls that have been sprayed as well.

I am in the process of cleaning cat spray out of a pillow top mattress cover. I am going to try some of your ideas, I will let you know what works!

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Some of the stains are old and some are newer. My dog is old and decided this is her toilet. We have to remove the rug and get in on the stains. It is a big job coming up. I can't send the picture because the rug is still on down, it is wall to wall.

By Millie

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Many people have pet stains on wood floor problems in their homes but often do not realize the extent of the damage because the floor is covered by carpet. One hot summer, we bought a 50 year old house, having seen it with doors and windows open on a hot breezy day. Only after we moved in did we find the really foul smell and stains in all rooms. After we stripped the carpet, we found very large and clearly repeated stains with, again, the awful smell.

The problem is that the urine, feces and vomit soak into the wood and, over time, essentially become part of the wood-stain, smell and all. We tried many cleaners and even sanding, but, finally, realized we needed a new wood floor.

I hope your problerm can be resolved with surface cleaners and you do not need to pay for an expensive new floor. Good Luck!

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Which Kilz primer would I use on the subfloor to cover urine smell, the latex or oil, or the primer and sealer? Can I use the spray version?

By Deb S.

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This should tell you everything you need to know. As a former property manager, I have seen Kilz do wonders. And I found oil based is better, as it is water repellent. Good luck.

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I just ran into this problem a few days ago. Our sweet kitty managed to ruin a room in our house with his urine! I tried to steam clean it out, but to no avail! No matter what I put on it - enzyme cleaner, deodorizer - it would not work. The smell began to permeate my house, so it was time to take action!

Approximate Time: 3-4 hours - 2 days


  • 1 box cutter or utility knife ($8.00)
  • pry bar ($12.00)
  • sand paper ($1.00)
  • eye protection ($5.00)
  • fine particle mask ($5.00)
  • dishwashing gloves ($2.00)
  • bleach or bleach spray ($3.00)
  • Kilz or other primer ($7.00)
  • dollar store paint brush ($1.00)
  • new flooring alternative ($300.00)
  • (optional) black light ($20.00)


  1. Sadly, you have to pull up your carpet and padding. Trust me, there is no other way. Using your pry bar, gently pull up a small edge of your carpet. You can pull up the whole carpet in the room, or cut it into small pieces to make it easier to handle. Use a box cutter with a very sharp blade. It is easier to cut from the bottom side, and far easier to cut in a straight line, when possible. Make careful cuts in doorways so you keep the carpet outside of the room intact. Next, use the pry bar to pull up the carpet strips. Be careful, they are full of tiny spikes that held your carpet to the floor.
  2. Get that stinky carpet out of the house! Throw it away. If you cut it in smaller pieces, you might be able to fit it all in the trash can. (That's what I did.) Otherwise, you will need to haul it to a dump. You don't want to reuse any of it. The smell permeates the carpet.
  3. Find the urine spots. Usually, you can see the stains, even old ones, on the sub floor. However, a black light will help you see a few you did not know were there. Turn off the lights and turn on the black light. Have a pencil or piece of chalk handy. Circle the areas that glow, and be sure to circle about an inch around them - just in case.
  4. Turn the lights back on and start sanding. Be sure to use eye protection and a fine particle mask. The dust coming up is hazardous. You can sand by hand or use a sander. It does not need to be a fine grit - whatever you have on hand should work.
  5. Make a mix of 1 part bleach to 3 parts water. This will be strong, so keep on the eye protection and mask. Also, you will want to protect your hands with dish washing gloves. Scrub the area with the solution. Allow it to dry, then repeat. You may do this a 3rd time, if desired. You can also simply use a bleach cleaning spray, as long as it actually contains bleach. Allow the spots to dry overnight. Be sure to leave the house and return, to make sure the odor is really gone (you can get used to it if you don't leave the area for a little bit). If needed, sand and scrub a few more times. (My odor was horrible, but it only took me 3 applications of the bleach cleaner spray).
  6. After allowing the spots to dry, paint over them with Kilz. You can use a cheap brush from the dollar store for the painting. Allow it to dry. The odor should not return!
  7. Now, it is time for some new flooring. You can always have the area re-carpeted. However, if you are worried about a repeat performance from your pet (I was), then you will not want to have to pull up a room of carpet again. I went with seamless carpet squares. These truly are seamless if laid correctly and vacuumed. If the pet stains again, you will only need to remove one or two squares and replace them (be sure to order extra). Other alternatives are vinyl plank "wood" floors. These are completely waterproof and very easy to lay and cut. Tile is another alternative. If you are worried about more stains, choose something waterproof or easily removable, with minimal replacement cost.
  8. Follow the directions for laying your new floors.
  9. Clean up! If your problem is a cat, as mine was, be sure to keep the litter box as clean as possible. If the problem is a dog, crating the dog while you are gone works well - and it does not have to be forever, just a few months should work. Good luck!
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My dog ally has created an indoor potty for herself on the carpet. A friend has just pulled up the carpet for me. Now on the wood subflooring there are urine stains. What can I do to get the smell out of that wood? He suggested cleaning it with Febreze. Well, that isn't a cleaner. Then he said he could put more subflooring on top and then tile over it. Ii still think the smell would come through. Any ideas would be greatly appreciated.

Sandy from Baltimore


Kilz Primer

In my experience, the best bet is to clean it as well as possible. Let it try completely. Then apply a sealing primer like Kilz and seal the odor in. The primer smells pretty bad, but once that odor wears off, the pet odors should be trapped. This fix prevents you from having to replace the subflooring.

By Fisher

Bleach It

Bleach the hardwood floor. Use 1 part bleach to 1 part water. (05/08/2007)

By Superfed

Sand or Replace

I would suggest trying to sand it first, but make sure you are in a well ventilated area due to the dust and the urine getting into the air. Otherwise,you will need to take up the subfloor. I would "not" put subfloor on top of urine soaked subfloor, that would make it worse for you. In the summer with the heat what a smell that would bring out and why ruin more lumber? Just sand it out, if that doesn't work then replace the subfloor. Also, I would start crating the dog when I was "not" around. Good luck.

By grammaoftwo

Nature's Miracle

It's not a very cheap solution, but it does work, Nature's Miracle. Saturate where the dog used the floor, it should take care of the odors. You might have to repeat it several times; however, it is cheaper than new flooring.

By Melissa

Kids N Pets

There is a very simple product called "Kids N Pets" I bought it at WalMart. It works beautifully. Just pour some on the area let it soak in and then blot. I have done this on my carpet for doggy diarrhea and for cat urine on a couch pillow. It is all gone. I love this product.

By caraing

Baking Soda and Vinegar

I have 7 cats and when they have an accident, I put baking soda on the spot, wait 5 minutes and scrub. Then I pour white vinegar on it and scrub. You may have to do it a couple of times, because you don't want it to buckle the flooring, but from experience this does the trick.

By eyelovecats

Kilz Primer and Polyurethane

I have flipped many houses with the pet urine problem. Simple steps: Spray 1 to 1 bleach/water mix over any problem area. Then paint 2 coats Kilz over area. Next is the most important step that no one seems to do, spread 2 coats of polyurethane over the area to seal smell for good. Polyurethane is the protective coat that goes over finished wood floors so nothing penetrates and damages the wood. Lets nothing in or out. Final step is of course carpet or tile.

By Alex

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Home and Garden Home Improvement FlooringAugust 17, 2012
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