Thanks for the advice folks. We cleaned the OSB with detergent twice.
Then we painted it over twice. Then I put the wood flooring down.
Haven't smelled a molecule of cat **** since then. Even had guests over
for Thanksgiving and served them a huge meal within 3 feet of the
former **** spot....


Never Enough Money wrote:
My wife's stupid cat has used a corner of out living room to **** in
off and on for year - usually when the weather is bad outside she'l use
the corner instead of venturing out the cat door.

So, we decided to pull up the stinky carpet and put down hardwood
floors. Today we pulled up the carpet and discovered the OSB board
underneath also reeks of canine urine.

So we used a strong detergent and let it dry. Still there's the odor
although only half as strong.

I could replace the OSB but that's a lot of work. What if I paint over
it before putting the hardwood floor down? Do you thin any odor would
waft up into the room?

Thanks for your feedback.