Vet's and pet stores have enzme products that are suppose to remove the urine smells.

Surfaces may respond to enzyme treatment, but I have found that they often need to be sealed with a primer sealer. Fabrics are rarely recoverable. Not a good situation. Be sure to fix the cat. He deserves it.

thx tom, but i think i'mlooking more towards what to use and really if this house can be saved.... no exeragations most hog barns smell better it'll take your breath and stay with ya after you're outside

If there is carpet and padding you will want to remove both

Clean the floors very well and with a pet deodorizer.

You may even want to pull up the old tack strips as they may have been urine soaked over the years.

Then we still suggest that you apply at least one coat of the Kilz primer. We find that the alcohol based tends to be the best working of all of them.

We've found that solutions labeled as 'enzyme' cleaners work best, they generally run about $20 for a 64 oz. bottle. You may have to soak the area overnight (follow the label instructions), and/or soak the area repeatedly before soaking up the moisture. This should remove almost all the odor, and make the area unappealing to the cats for elimination. This is worth trying since it is usually far less expensive than the alternatives.

If this is not effective you may need to remove and replace the flooring, and underfloor as others have suggested.