Pet Urine On Wood Subfloor

29 Replies

My tenant who spent the last 12 years occupying my rental finally moved out along with her 2 small dogs. Well I knew the floor was going to be bad after the horrible urine smell that was left in the unit. Removing the old carpet and padding was pretty horrible due to the smell. Once we got the padding up I saw how bad the wood was and tried cleaning it with bleach and a mop to get the smell out.

I'm debating if I should just remove the subfloor and replace it with new wood. It's something I really don't want to do but will if I have to. I do have one small area that will have to be cut out and replaced. Yesterday I put down some Natures Miracle Urine Destroyer and waiting for it to dry to see if it helps with the smell. If it does I can apply some Zinsser BIN to seal it and install new flooring. What do you guys recommend? The floor looks pretty bad with stains. I've never seen one this bad but I don't have much experience with rental properties.

Snapped a quick pic of the floor. This was after about 48 hours of applying lots of bleach and a mop with the windows open. I know have a fan in there helping to dry the floor.


@Guevara M. that looks pretty bad... and I've dealt with this a few times in the past. Cats are often much worse! But either way, if that neutralizer helps, then yes, you could try to apply Zinsser or something similar to lock in and seal the odor should the wood itself be strong enough and not 'soft' however you have some other options.... How thick is the finished floor of the neighboring rooms? As an alternative to removing the existing boards, you could apply Zinnser or Kilz (at least a couple coats) then add 1/4" Luann or 3/8" plywood over the existing once its' been sealed then apply your finished flooring. This just help to both seal and strengthen the existing subfloor. The only drawback to this is making sure the finished floors and baseboards can allow a slight increase in height as they transition to other rooms.

That said, if this photo is showing the majority of the issue, I'd just replace those 3-4 boards and move on. They look to be the worst. If the other areas aren't as bad, you could just try to seal them as well without having to replace or add anything over them.

Good luck with it

My inlaws are going through this same situation. They're keeping the subfloor and priming it with Kilz. They've already tried natures miracle urine destroyer and after a few weeks could still smell the urine. I'd either replace or put down some kind of primer. Good luck!

@Mark Gallagher has it right.  A 4x8 sheet of OSB or plywood is going to cost you about $20.  It's going to cost a lost more in urine remover, BIN, and mostly time than just replacing it.  Replacing it is a guaranteed fix, the others are a maybe.

Not sure why the tagging thing doesn't want to work... 


that's bad

no matter what you put down over a little time the smell is going to come back

save yourself the headache of chemicals and a smelly home

looks like a couple sheets should be a easy tear out

make sure your lease says no animals-


Thanks for the replies. I'll probably replace the areas with new plywood like you guys have have mentioned. Should only need 4 sheets to get it all done.

Replace the plywood sub floors.. if the wood has soaked thru,, to joists,, prime joists with the Kilz oil based primer..  Cats are worse

We did a cat pee house,,, removed subfloors, and door jams, and sheetrock about 24" up on just about all walls.. and used a kilz primer on joists before putting down new  sub floors. 

So don't rent to people with pets,, lesson learned

Definitely will not be allowing pets again. This was the huge lesson learned for myself. I'm going to the property in a few hours to check it again and will most likely end up replacing it.

I actually had this problem in an upstairs room of my personal residence when I purchased it.  The cat they had apparently used the entire room as a litter box.  It was the worse carpet removal I've ever been a part of.
I didn't want to use Kilz because I was afraid it would seal the smell into the floor and then let it seep through the ceiling of the room below.  I decided to try the Dutch Boy Refresh paint before tearing up the floor because I figured at worse I was out ~$30 and at best I'd save a ton of work.  I ended up painting the entire subfloor and walls with it, after sealing the ceiling with my normal CHB.  The next day the smell was completely gone, I couldn't believe it.  It also never migrated to the room below.  I wouldn't recommend "Refresh" for general painting, there are much better options, but it is now my go to odor eliminator.  

@Guevara M. , I almost threw up looking at that picture. Replace. 

I have to leave this page, I'm going to vomit. I can smell it from here.

Devils advocate, if you charged a $25 a month pet rent with a non refundable pet deposit for the guaranteed floor replacement, think of how much extra cash you'd make if the next tenant with pets stays 12 years! You could just pay someone to do the floor repair then and voila lovely fresh flooring for next tenant :).

That said, in my own personal home our cat stopped using her litter box and we fought the good fight and solved the problem in under a month and cleaned the afflicted area daily and still had to pull the carpet and the one sheet of subfloor she targeted. It was terrible, I can't fathom 12 years.

I've ran into this exact problem and my property manager had a good solution for it. He would seal the wood with an epoxy or urethane and install carpet or flooring over top.

Im a general contractor ,and entry property investor , with years in property management maintenance ,, youre best bet is to replace the sub floor , ,i wouldnt replace floor coverings over that , its too permeated with pet urine ,  you can try sealing ,but if odor persists you'll have to pull carpet /flooring back up,   John @ 4 Aces Construction   cc 4acesac84302

We get called in on quite a few of these and had a couple of my own over the years.  With this much urine, you're always best to pull and replace the subfloors AND prime & seal over any damaged framing with an oil-based primer like Kilz...the cheapest version works the best.  With that amount of urine, it has soaked through to the underside which you can't seal from to replace.  We've mostly moved to a no pet policy with most of our rentals.

@Guevara M. I'm with the folks above, replace.

Keep in mind that it might not smell if you seal it but once the heat goes on it's going to stink the whole house up all over again.

Thanks everyone for all the advice. I really appreciate it. Since this unit is on the 2nd floor do you guys think I will have any issues with the ceiling of the unit under mine when pulling and replacing the wood? I'd hate to cause their ceilings to crack.

Started removing the subfloor today. Installing new plywood tomorrow.


I am working on a large rehab house now with dog urine on the subfloors.  We have replaced approximately 25 sheets of subflooring.  I left several spots that I thought we would spot treat and seal over.  As the humidity is getting higher outside I have noticed the spots all sweat (moisture seems to condense on them. I believe it is from the salt and other chemicals in the urine).  The spots get darker in appearance and smell a lot worse.  I am certain if we treat and seal, the smell will still permeate through the plywood around and under the sealed areas.  I am not willing to chance it on a large rehab project.  We are going to cut out the rest of the areas in 16" x 12" patches and glue/screw the patch down.  I am not willing to sell a house that smells like fresh paint now but get comments on our facebook page from new buyers that on humid days their new house smells like dog urine.      

Oh my god, that's horrible. I lived in an apartment for a year where the previous tenant had cats; the landlord covered the smell pretty well when i saw the unit but after i moved in it was clear that the odor was there to stay. Even still, I can't believe the damage that this caused to your floor.

I'm dealing with this right know, except its on beautiful hardwood floors that the carpet covered.   I don't allow pets but it was an inherited tenant.    Bleach, Scrape, scrub.  Bleach, Scrap, Scrub, floor sander, bleach, shellac.

though if its just a section of subfloor i'd probably just cut it out.   I wouldn't want to risk buying new carpet and having the smell come through.

I am super late to the game here, however wanted to share... 

I purchased a house that had just this all over the entire place, Plus smoke smell and weed smell :) It was horrible. I used layers of Oil Based Killz paint on the whole place. The house smelled BRAND NEW! I lived in it for a couple of years and my dog didn't even pee inside (And he is an ******* that would) :) 

@Guevara M.  My mother had that happen in one of her rentals, but it was hardwood underneath the carpet.  We were able to take a couple layers off of the hardwood and refinish them saving the floor.  Looks like you made the right decision.  Hope all works out.

Hey, I just wanted to add my experience with dog pee.  PetCo or PetSmart sells a product call "Simple Solution" that is an enzyme that "eats" the dog pee.  

Short story we moved into a home, dog pee EVERYWHERE, we thought we would start with bleach (after all carpet pulled out mind you; this was over slab on the bottom floor and OSB on the 2nd floor) and pump sprayed bleach water everywhere to disinfect it.  Let it dry a day.  Then bought the Simple Solution, but couldn't tell if it needed to be watered down or sprayed directly or what (it was a gallon jug), so I called them and they said dog pee, specifically, dries to an alkali, and to bring the Ph level back closer to neutral would help the enzyme work better, so they advised to spray a white vinegar/water 50/50 solution on the pee spots and then let it dry.  

Well, we just pump sprayed the entire area, and it was disgusting because the vinegar would make the dog pee congeal due to the chemical reaction, so we found spots we didn't even know were there!! (We sprayed everything 3' down on the walls and all flooring...So did the dog..LOL)  Then let that air dry for a day (with fans going to circulate the air. 

The following day we sprayed everything down with the Simple Solution and again, let it air dry a day.  No smell after it was done!! Then the carpet was installed a couple days after that.  I lived in that house for 8.5 years and NEVER smelled dog pee (I'm not a dog person, I would have never have stayed if I smelled anything).  So, I tell everyone who asks about this product because yes, you can cover and seal and and and, but cleaning will not get rid of dog pee, and now I know it is an alkali when it dries, I know to use an acid to help  clean it (vinegar), and the enzyme to digest it.  YMMV.  Also, I have no affiliation with Simple Solution, I'm sure any enzyme treatment would work; it's knowing how to get the Ph that was most helpful to me, and to ensure there's no confusion, this is not an advertisement, I'm not affiliated with any company, I'm an insurance adjuster....