Rental Property, Cats, and Carpet

Question:

I have a rental property and the tenants have cats that have urinated on the carpet and it has permeated into the WOOD sub-flooring. Is there anyway to get rid of the smell besides replacing the sub-flooring itself? 

Thank You,
Suzan

Reply:

Cat pee really stinks.

Cleaning spots of dog urine is easier... I've done lots of that. I have simply washed urine puddles with some sort of ammonia-containing liquid, either household ammonia or (believe it or not) ordinary Windex. Then I would use several dry paper towels to absorb the liquid. Supposedly most animals hate the smell of ammonia. I know that our dogs stay away from spots treated with ammonia. Part of the idea of using ammonia as a cleaner for urine stains is to prevent the animal from repeatedly urinating on that spot. It's always worked for me... with dogs.

I have dealt with a large cat urine stain like what you described... The house I presently own had a serous smell of cat pee in a bedroom closet when I moved in.

It seems that there are two situations - replacing the carpet or keeping the carpet.

1. Keeping the carpet: 

Before moving into my house, I rented a Rug Doctor carpet cleaning machine. But I bought carpet cleaning solution from Home Depot... their ZEP brand was cheaper than the Rug Doctor rental place.

I vacuumed the carpeting and then used the Rug Doctor, following their directions. Actually, I only noticed the smell of cat pee after using the Rug Doctor, because wetting the stain must have liberated the odor-causing chemicals.

I bought a bottle of pet odor removal chemical from Home Depot, and sprayed it on the stained area. Then I washed the spot with the Rug Doctor. That did NOT work. Then I poured the pet stain chemical into the cleaner compartment of the Rug Doctor... that worked better, but I could still detect a fairly strong smell.

I got rid of the smell, however... I cut out the carpeting and padding in the closet. Luckily there is hardwood flooring under the carpet. But this solution won't work for most houses.

I believe the padding was the real problem. When I peeled back the carpet, the padding smelled far worse than the carpet.

I also had minor cat urine odors in the living room, and I was able to remove those with the Rug Doctor and pet stain remover. I'm guessing that the urine didn't soak into the padding.

Here's an idea, but I'm not sure how well it will work:

• Peel back the part of the carpet with the stain,
• Remove the stained padding,
• Clean and prime the wood underlayment with B-I-N sealer (see below)
• When the primer is dry, lay a tarp or sheet of plastic over the primed wood,
• Lay the stained carpet over the plastic,
• Clean the carpet with a Rug Doctor or other carpet cleaning machine, using a strong solution of pet stain remover on the stained areas,
• Dry the carpet with plenty of large fans,
• Install new padding, which is simply stapled to the floor,
• Lay the carpet in place and stretch it back into position with a carpet kicker (painful) or stretcher (newer, better tool). I'm told these tools can be rented, or you can have a carpet installer do the job for you.

I suggest this approach because I suspect that the padding gets soaked with urine but is almost impossible to clean with a Rug Doctor because the padding is so far below the top of the carpet. I also suspect that cleaning the carpet while leaving the padding in place might actually draw some urine up into the carpet, which is why I suggest removing the padding and placing plastic beneath the carpet before trying to clean the carpet.

Unfortunately, this is a big job. Did I mention that I don't like carpet?

2. Replacing the carpet: 

I would splash some pet stain cleaner on the stained wood underlayment, let it soak in, mop or vacuum it up, and then rinse.

When the wood was dry I would apply a coating of Zinsser B-I-N Primer/Sealer, which is a shellac-based primer that is very good at covering up odors such as smoke caused by fires. Their product literature mentions a long list of stains that B-I-N sealer covers, but they don't mention animal urine. Other people have told me that B-I-N sealer does seal up urine stains and prevents the odor from returning.

I would seriously consider priming ALL the wood underlayment, to prevent future stains from being absorbed into the wood. A gallon will cover about 400 square feet. You can but B-I-N sealer at Home Depot and most paint retailers.

Bruce W. Maki, Editor.