There is a product called "Odor-ban" I got mine at the Sam's Club. I had a rent house and when the renters moved out, we found that they had been locking their dogs up in the back porch. not only was it in the concrete, but the framing, and walls. we had to gut the whole room. it still stunk! You couldn't even walk in there. Anyway, we tried a variety of treatments, nothing worked. We got a commercial product that was "guaranteed" to remove the odor. All we got was urine and oranges....i dont know what was worse?? WE then tried odor ban. Got it for appx $10/gallon. Poored in on straight. Let it dry. and re-applied. Worked great. Smelled clean, but no longer smelled urine. Give it a shot!