I am continuing with my series on questions from readers with answers.
Rick writes and asks "Can you please tell me more about the odor neutralizer? I am working with concrete that has been used in a dog day care / kennel for a couple of years. So far I have tried a degreaser/cleaner, enzymes (which included covering the floor with plastic for 24 hours to keep it wet), white vinegar, a high-tech odor neutralizer, and finally bleach, both straight and diluted. I have power-washed at the start, and again after each of these treatments. The bad odor has been reduced but it is still present."
Thanks for asking. Concrete is porous so what you have is a situation where dog urine has been soaking into the porous surface (it sounds like continuously) for a couple years. At least some of the products you have used are working. The enzymes work by digesting the urine residue. The reason you keep them wet its two-fold. One: They have to be wet to be active. When they dry they do nothing. Two: To get them to soak into the concrete far enough to reach the urine, which would be in pretty deep. Bleach uses oxygen to break down the urine. It will work also if it can reach the urine in enough concentration and for a long enough time to work (which for oxygen is fast). Washing is good and it will remove the urine it can get to. You do need to be careful with power washing though because it can drive the urine even deeper into the concrete depending on how you do it. Neutralizer you asked about also has to come in contact with the urine to change the molecules. So your challenge is to get one of these (a good product) deep enough into the concrete. Where the urine is after a couple years of soaking in. One suggestion is to apply a product and keep it wet for several days. The longer it is wet the deeper it will penetrate. Also make sure that the urine smell is not coming from surrounding items. Is there wood close that might be contaminated or fabric or even dirt. Urine will wick up several inches into other materials when present. It is common not to be able to completely remove all the odor in a situation like yours. (concrete or even wood) So an option used by professionals is to seal the concrete. After you have removed the majority of the odor you can then seal the concrete with a good pigmented shellac, varnish or acrylic sealer. These sealers have microscopic holes left in them when they dry. These holes are larger than the odor molecules so odor can still get through the sealer. If you apply two coats of sealer this will help eliminate that issue. The end result is a completely satisfactory odor neutralized environment. Get back to me with any additional questions.