Pet Urine Stains on Sub-flooring

April 15, 2013

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!

Total 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.
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  3. 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.
  4. 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.
  5. 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.
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  7. 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).
  8. 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!
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  10. 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.
  11. Follow the directions for laying your new floors.
  12. 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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5 Questions

Here are the questions asked by community members. Read on to see the answers provided by the ThriftyFun community.

June 25, 2010

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


Bronze Feedback Medal for All Time! 180 Feedbacks
June 29, 20100 found this helpful
Best Answer

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!

September 30, 20100 found this helpful
Best Answer

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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April 24, 2013

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.


Bronze Feedback Medal for All Time! 101 Feedbacks
April 26, 20130 found this helpful

I am not sure Kilz would cover the odor. You might have to shellac it to be sure.


Gold Post Medal for All Time! 969 Posts
April 26, 20130 found this helpful

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.

October 19, 20161 found this helpful

A horrible cat odor from the next-door (this is a row home) was suddenly getting though to our basement. After sealing all cracks, joists and undersides of the subflooring out to 1 foot with mortar, foam, caulk, and Drylok, the smell was still as strong as ever. A fellow in a video said that shellac is the sealer to use here. I am nearly overjoyed to report that after 2-3 coats of shellac over everything (including the Dryloked party wall), the smell has finally abated. The product we used was:
Zinsser 1 gal. B-I-N Shellac-Based White Interior/Spot Exterior Primer and Sealer $41.98 at Home Depot (the can may also say Rustoleum - they merged with Zinsser)
It's an ethyl-alcohol based (make sure the ventilation is adequate!) liquid that's as thin as skim milk. With a 1-1/2" brush I daubed it into and over the foam, caulk and Drylok, into every nook and cranny, and then with a wide whitewash type brush I did the wall down to the floor. One gallon covered about 100 sq. ft. in 2-3 coats You don't need to work it like paint - it's not paint. You just need to get everything wet. It dries in 45 minutes and then can be recoated. We put the recommended two coats on, and then for good measure a third in the areas we suspected were the prime offenders (when the whole room stinks, it's really hard to pinpoint the source).
After all I was glad the surfaces had already been sealed with the Drylok. I think a lot of shellac would be wasted if it went on a porous surface. I believe they can tint the stuff. Putting white on white, I had to rely on the wet shininess to see coverage, and I do believe that absolutely every square inch must be sealed for it to work.
Having sealed every hole, no matter how tiny, the wall is now airtight, and the shellac seems to live up to its promise (I think there's a money-back guarantee on the stuff). There is nothing more demoralizing than spending lots of time and money to refurbish a place, only to have it made uninhabitable by this most foul of smells. We wish you the best of luck.

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March 20, 2015

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


Bronze Answer Medal for All Time! 220 Answers
March 20, 20150 found this helpful

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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ThriftyFun is one of the longest running frugal living communities on the Internet. These are archives of older discussions.

August 24, 2009

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.

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