Are the white and dark spots on my subfloor mold or mildew, and can I simply apply oil-based Kilz over them after pulling up carpet with dog urine stains?
Asked by Michael Williamson 
3 months ago
Last Updated: September 27, 2024
Hey, do you think those white and dark spots on my subfloor are mold or mildew? Can I just use oil-Kilz to cover it up? (Just so you know, the fourth picture is a closeup of the third one). We recently removed the carpet, which had a ton of dog urine. Thanks a bunch!
I notice quite a bit of mildew, dirt, and mold, although it doesn’t seem to be black mold. There is significant damage to the subfloor. You could try using Kilz on the floor, but I’m not sure if it will provide a long-term solution, and the odor might still seep through. If the floor can be salvaged, it should be thoroughly cleaned and well-aired. Do not place anything on it until it’s completely dry. If it were up to me, I would remove the damaged sections and replace them.
Replace it promptly to prevent the odor from returning to bother you next summer 🤢
Is this for an indoor floor? Investigate the source of the rot hiding behind the walls. This kind of deterioration isn’t only caused by pets.
Try CLR to get rid of mold and mildew, followed by using Kilz
Hey Heather, I jumped the gun a bit… my bad. I missed the part about dog urine. The best course of action would be to replace the subfloor. That smell could return and become a problem. But if you absolutely can’t replace it, then stick with my initial suggestion.