Getting rid of pet odor (urine)

[Gary Marcotte]

I have a HUD home under contract and when I did my initial walk-thru there was a heavy pet odor in the house. Not just musty dog smell but a stronger one, like urine. Not sure if it is dog or cat or both. I believe it to be all the way through to the sub-floor (plywood). Was wondering if anyone has a remedy or experienced any trial and error ways of getting rid of it? I'd like to avoid a costly "professional" cleaning if possible and/or a lot of trial and error of my own.

Any help would be greatly appreciated.