I rented my house to a retired military vet, who claimed he knew what clean meant. When I got the keys to the house back, I had to enter with vesperator masks, as the smell was so bad. The entire house was covered in urine. I tore all of the flooring out, including tile in the kitchen and hardwood stairs. I washed the walls with a urine gone solution and vinegar. I then used Kilz everywhere. In the basement I used my nose and sniffed along the wall - marked several areas and removed the drywall in those sections. All baseboards were removed too. I run an ozone machine every time I am there.
I thought I got it, painted the walls, installed new floor and baseboards. And now the AC failed and the smell is back - only in the basement though. There are pockets of pee smell and overall the area just smells, and not pleasant.
I don’t know what else to do. I wanted to rent it again, but I may need to sell. However, I won’t be able to with that smell either. I am about 20k deep in the renos. I can’t really afford to rip everything back out. Any suggestions?
Have you tried Odor-Xit? May be difficult with the Kilz already down.
I recently had a cat pee house. Lesson learned - get a black light and treat the pee before using kilz. A black light might still be helpful now to see areas you may have missed. Washed with TSP and Enzyme treatments. Another pass with kilz helped my problem area. Also here’s another vote for odorXit.
I have no experience with this issue, but I wonder if the smell may be in the ducts. Perhaps you can have a company come clean them.
Ditto on the black light. Once you've identified the areas, the shellac based Kilz will effectively treat it. Haven't used odorXit.
Cats mark, so usually something that bad means taking out the bottom 4 feet of drywall (as in a flood) and putting new drywall up there - and maybe sealing the studs underneath before doing it, and/or changing out the insulation depending on how much saturation the drywall received. You say the smell is now only in the basement so it appears you've hit the worst of it upstairs. That means you need to think about what you didn't work on downstairs. You just used your nose and took off drywall where you thought it smelled. Perhaps you missed areas. Perhaps the urine went through the drywall and into the studs or insulation. What about the floor covering?
There's only two real solutions to cat urine issues, especially that bad - seal it in or remove the products. If you go for the seal it in route, you need to use non-permeable surfaces, like solid vinyl, or put down a poly barrier sealed before putting a floor on top of it. Same thing with drywall surfaces. I bought a house once that was like that, the smell when you came in would make you pass out, and this was with hardwood floors. I had the entire floors sanded, sealed, and multi-coat polyurethane, and that combined with new paint top to bottom (these were concrete, not drywall, walls) sealed the smell, and that was several years ago with no return.
What did you to the concrete floors? If you just washed them then the smell is embedded into the concrete (its porous). You need to seal up the concrete. You need to stop vapor transmission. You might need something more than just paint.