I've got a serious cat urine problem

8 Replies

I bought a property about 2 months ago from an elderly cat lady. I couldn't believe she was still living in the house - it smelled so bad - just burned the eyes. I've purchased lots of cat pee houses and even own one that was worse than this one. That one was so bad you needed a respirator just to go inside AND IT STILL STUNK! I gutted that property, put in new drywall all along the bottom 24" and rented it out. Been rented for years and never a complaint. 

This new house wasn't bad once we get all her crap out that she left behind. I thought airing it out for a few days and giving it a bath in Odorxit would do the trick. We even sanded the hardwood floors and varnished them, twice. The house still reeks. It is a raised foundation and all sand underneath. I smelled the air near one of the vents and the cats were definitely using the sand as a litter box. I made 1.5 gallons of Odorxit (from concentrate) and sprayed it under the house soaking the sand. The tenant said it still stinks. (Yes, I rented it out like this. I'm a jerk.) I went inside and sprayed Odorxit all along the baseboards and floor within 6" of the walls. The tenant said it still stinks. 

I did some research online and found this product BioKleen that I'm going to order and try. At this point, I'm thinking I need to remove all the drywall along the bottom 24" of the walls on this house too. It is just horrible. 

Any other suggestions? What are some of the things you've used to kill that horrible lingering ammonia smell?

(Disclaimer - when I say "I" I mean my contractor.)

Hey Aaron - you're certainly on the right track. 

Strategically, you have to either remove the source of the odor (porous material), seal or encapsulate it.

The drywall and baseboard trick you mention is important. Since you're dealing with a raised foundation, once you remove the existing floor covering and expose the subfloor you'll need to neutralize any remaining urine by using pool bleach and water applied with a weed sprayer. 

Whatever you seal, make sure you use the oil-based Kilz product as the alcohol-based product gas not proven as effective at odor control.

Lastly, rent (or buy) an ozone generator. Leave it on at night during renovation for the sanity of your contractor's workmen and plan on leaving it on 24/7 for several days to a week after renovation completed, as necessary.

You can call me directly today in route to the ranch.

Thanks for sharing that Rachel.  I love Nilium.


There is a specific brand of kills primer that is specially made for fire damaged houses encapsulating and covering smoke smell. It works really well on the walls instead of tearing out drywall for cat smell too. Wish I could remember the name, but I haven't slept in a few nights with the big move, so my brain is fried. You may have to abandon the hardwood floors and spray over them as well, then put flooring on top of painted hardwood.  But some people like painted hardwood floors. I tell the tenants it shabby chic design. Lol

Hey @Aaron Mazzrillo , the last time I had a bad cat urine smell I tried several fixes, but ended up painting the hardwood floors with oil based Kilz, then after still smelling it, I ended up sealing the walls too.  That and the floor paint did the trick for me.  I have never tried an Ozone generator, and I have heard mixed reviews.  What do they do to help reduce the odor?

I'm afraid your problem might be the big litter box under the house. And I have no idea how to deal with that other than get the top layer of dirt/sand out of there. Would that even be possible? By raised foundation do you mean a crawl space? Or is it just tall enough for cats, etc, to get in? 

Can you use one of those pee lights (blacklights?) to see if it's the drywall before you start tearing out?

This is not fun but find out where the smell is coming from, get down on your hands and knees if needed. Cats have favorite places so there will be one or two or three locations where they did their business. Find those and remove the impacted area. I don't buy the Kilz solution. Kilz is shellac which cracks and those cracks let the gas escape to your nose.

A few of thoughts

Are you sure your contractor did a good job in the crawl space? Again there is probably only a couple of concentrated locations where the cats actually did their business (assuming there weren't 20 cats). Find those locations and remove the soil. Sprayed OdorXit won't penetrate the soil adequately to reach the depths that the urine saturated. You might try an ozone generator in the crawl space when the tenant is gone. Finally, cover the crawl space soil with a plastic vapor barrier.

I like the remove baseboard and bottom two feet of drywall. The urine can run down the wall behind the baseboard. Here I would try and find the location with my nose so you don't have to tear up the whole house.

Are the kitchen cabinets finished to the ceiling? Cats can get up on top of the cabinets and  do their business there. Check that with your nose.

Also what furniture was against the walls? There maybe locations where they got on a piano or dresser and relieved themselves on the walls. Again paint and primers cracks which allow the gas/odor to escape.

The hardwood floors - if the urine penetrated/saturated the wood the OdirXit won't penetrate the wood grain adequately to neutralize the odor. The odor then goes into the crawl space via the gaps and voids in the unfinished underside of the wood. Only solution is to remove the wood. I would do the discolored/stained areas.

I currently have a cat house. It got lots better after I removed the hardwood floor in the area where it was warped from the urine. It was the favorite spot under the piano.

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