Urine Odor out of Concrete

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.

Dog Urine Concrete

dog urine concreteI am going to answer a question that was posted for me a little while ago. It is to do with the white powder or residue left from dog urine on concrete. This white powder many times is visible on concrete and not visible in other situations. It could be present but not visible on carpet for example. If the residue is heavy you will see it on carpet also. The question left for me was this:

“There are many white stains on our concrete path from my dogs urine. Is this white reaction  from the concrete or a stomach problem.

The reaction is neither a stomach problem or a reaction to the concrete but a condition created from the urine. When urine leaves the body human or mammal it is slightly acid (or acidic on the ph scale). The urine begins to change as soon as it leaves the body. Uric acid in the dogs urine is broken down into ammonia and carbon dioxide. The ammonia is high alkaline on the ph scale. The reaction from the acidic urine and the ammonia creates alkaline salt crystals. This is the white residue left on the concrete from the dogs urine. A good acid pretreatment wash will neutralize the alkaline salt crystals (white residue). Once neutralized it wash’s off easily with water or another neutral cleaner. If the urine has penetrated deeply into the concrete you may want to use an enzyme digester or oxidation product to deal with any smell or other residue. But the acid cleaner will remove the alkaline salts (white residue) left from the dog urine on the concrete.

Urine Odor and Concrete

Gray Concrete Getting urine odor out of concrete. Concrete is porous and urine will seep deeply into the pores and be difficult to remove. The specific steps for removing urine odor from concrete, as with most surface’s, depend on the circumstances. The main questions to be answered are how sever is the contamination? And how porous is the finish of the concrete. Slick finish or a finish made to seal the concrete, or hardened concrete allows very little urine to penetrate it. These finishes are usually found when concrete is the final surface or the finished surface intended to be seen. Concrete that is going to be covered  by carpet or some other floor covering is usually more porous. This allows urine to penetrate deeper into the pores of the concrete. It becomes more difficult to reach and the process takes longer.

For heavy concentrations of urine start by washing the concrete with a good acid side pretreatment. This will break down lipids (animal fats) and alkaline salts present from the urine residue. This will remove a large part of the urine quickly. This pretreatment can be presprayed on then give it time to work and rinse off. Or it can be mopped on and rinsed off with clear water. Following this acid side pretreatment wash, then follow up with heavy application of  a good urine enzyme product. Allow this 2 or even 3 days to penetrate deep into the concrete and then come back and rinse or mop with clear water. The enzyme product needs to be kept wet for the entire time so the enzymes can digest the urine odor residue and neutralize it. It needs to come in contact with the urine and stay wet or damp long enough to work. In the case of concrete it needs time to penetrate and then work. You can repeat the enzyme treatment if needed. You can also finish this process with a good sealer (shellac, varnish or acrylic sealer) to seal in any remaining urine odor.

If you are working with a smaller area or you do not have the time to wait for an enzyme product (2-3 days) I suggest you use a good urine oxidizing chemical. These are also effective if you don’t have the  2-3 days.

Use plenty of ventilation with any method. Gasses are being created that should be diluted with fresh air and ventilated to the outside.

Creative Commons Licensephoto credit: shaire productions