ACE said:
replacement
pad, carpet and tack strip
shellac base sealer for sub floor.
Zinsser's BIN is better than Kilz IMO
have they gotten rid of the cat yet?
if not, you're pi$$ing in the wind (pun intended)
if in an empty, pull back the carpet.
The urine stains will be obvious from the back.
remove and discard contaminated pad.
mix OxyClean mixed hot in large watering can.
Saturate the contaminated areas of carpet, allow dwell time, flush/rinse extract both sides of carpet
Note; cats just don't pee on the carpet.
Toms also spray along the perimeter of walls/baseboards , door jambs and furnishings.
That has to be addressed too or stink will remain
(even if you got rid of all carpet, pad, tack strip and seal subfloor)
don't neglect to wash and seal those hard surfaces .
..L.T.A.