I've heard of instances where homeowners have had to jackhammer concrete out to eliminate the cat urine odor so saving a hardwood floor which stinks that much is a longshot. If you have time, though, try plenty of bleach because the floor is already in bad shape so, really, what's the worst that could happen?

Well the bleach may work but I doubt it.. If it was a serious issue the urine may have soaked into the wood and no amount of bleach will remove it or even sanding. If the home has the original floor from before like 1980 and has never been refinished since then it wont have a polyurethane coat most likely a wax coat and would mostly been stripped away if it hasnt been done in awhile.. so I think you have little chance of salvaging the floor. after you rip it up and it still may not remove the odor sealing sub floor with a stain sealer like Kilz does help but also the rest of the home may need it as well to seal in all the odor cats spray on EVERYTHING so the walls are probably covered as well..

Use Murphy's oil soap which won't ruin wood first to wash the floors. It will neutralise the urine. Use it damp, don't flood the wood floor. Set up some fans to dry it. Then hire a pro floor refinisher to sand all the floors then seal/apply urethane. The feces is not the problem except perhaps for the stains. The smell will dissipate. That's why the house is a fixer. Sounds like some old person lived there and was too feeble both physically and mentally to provide proper litter box for the cats.

All urine is acidic. If you use an alkaline detergent and scrub the floor it will neutralise it. You may have to get this liquid detergent from a Janitorial supplier. In the UK it's called 'sugar soap'.

Spray the floors with the "Orange Gel" degreaser. It will smell like citrus but when the orange smell leaves the urine smell will also be gone.

Doing some real estate shopping. Found a very nice old home in rough shape, but a good price.

The problem is cat urine smell. You smell it through an open window before they even open the door. Seems to have been an ongoing problem that they just neglect. The whole house wreaks. You can see petrified cat feces on the floor too.

If I were to replace the flooring, even with low end hardwood click-lock or better grade laminate, we're talking $2000-2500 for the materials, a lot of labor to remove the old wood, which is solid maple, and a shame to throw away. Forget the 2-3 days labor I'd put into it.

Will sanding and refinishing take care of the odor?