@Paul Miller, Sometimes banks are aware of specific problems like this and will negotiate accordingly and sometimes they are not aware. You will probably need to call the person that has it listed and ask them if you can submit your evaluation of the property to the bank (or asset manager). It's worth a try but sometimes they will only make price adjustments after a certain amount of time passes. If it doesn't sell for a long time, they'll know they have a real problem on their hands and will start dropping the price.
I've run into the pee problem many times (I'm working on one now) and have done a lot of remediation research. Tearing out the soaked wood is always the best option for a very badly soiled house. If it's not that bad you can try a combination of several things.
-Enzyme solutions are available at pet stores and do a great job of eliminating odors because it's basically good bacteria eating bad bacteria. Pour it on and let it work.
- Bleach will kill bad bacteria but it also kills good bacteria so you can't use it at the same time as an enzyme treatment. It's also horrible on your lungs so be very careful. A full-face, chemical respirator in mandatory!
- You can rent an ozone generator from your local equipment rental store. Ozone will kill anything living inside the structure so be careful with it (remove plants, people, pets, etc). This will help with the general odor but it won't penetrate the wood to kill buried bacteria. This is usually not very effective with pet urine.
- If you choose to cover it with something there are only a few things available that will stop odor molecules from re-entering the room. Paint, Kilz, stain, etc are too porous so odor molecules can find their way through. The preferred coating is shellac. It's molecular structure is very dense so it works really well. It's available online or Lowe's and Home Depot.
Good luck!