The presence of water causes the uric acid to release a gas, which creates a strong, foul odor. Use your nose or a UV flashlight to find the urine. A UV or blacklight can sometimes reveal the site of an old stain, which can be helpful if you’ve already washed the floor several times and there’s no visual sign of the urine. Turn off the lights in the room and hold the UV light one to three feet from the floor. The stain may show up as a yellow, blue, or green mark. Use a piece of chalk to mark the spot if you only plan to spot-treat the floor. If the UV light doesn’t work, you can also try smelling out the spot.

Air the room out and then simply sniff the room until you’ve zeroed in on the area. Though you probably want to pay extra attention to these spots, possibly treating them more than once, it is recommended you treat the entire floor so you don’t miss any spots that didn’t show up under the UV light. Treating the entire floor will also keep your floor from appearing spotty—if the treatment causes the concrete to lighten and appear cleaner, it will look better if the entire floor is a clean and uniform shade. Make sure you wear protective goggles and rubber gloves, as TSP can damage your skin. Pour the TSP mixture onto the floor and use a scrubbing brush to lightly scrub the area. It is important you do not allow the TSP to dry out too quickly.

It should sit wet on the surface of the concrete for at least 5 minutes. If the mixture dries before 5 minutes have passed, add more TSP mixture or water to the area. The longer it remains wet, the deeper the mixture can penetrate the concrete. You will probably notice the urine smell grows very strong as you pre-treat the floor. This is a normal reaction of the uric acid crystals and the water. This will remove much of the spent TSP solution. Then rinse the floor with hot water twice more and allow the floor to dry naturally overnight.

Don’t use fans to speed the process along—your goal is still to saturate the concrete and loosen up as much of the urine residue as possible. Then turn the machine off and spray the inside of the dirty water tank. Prepare the enzymatic concentrate according to the instructions. Some cleaners must be mixed with a carpet cleaning solution, while others just require the addition of water. Follow all instructions carefully, and be sure you don’t dilute the concentrate by adding too much water. Make sure the floor is entirely dry from the pre-cleaning the day before you begin applying the enzymatic cleaner.

Saturate the area with the enzymatic cleaner. You want to work in small sections of about 3×3 feet. Use enough of the solution that there is standing water on the area for at least 10 minutes. Add more solution if the area begins to dry out—again, it is essential the liquid permeate every layer and every pore of the cement so it can break down the uric crystals. Be especially aggressive in areas where you noted the urine stain with the UV light. You may want to get a scrub brush and use that to really work the enzymatic cleaner into those areas.

The most heavily marked areas may bubble. Take note of these areas, as you may need to treat them again if the smell persists. Repeat the process until you have treated the entire floor. Allow the floor to dry overnight once you have finished your treatment. To prolong this process and give the enzymatic solution more time to work, you can cover the floor with a plastic tarp. This will slow the evaporation rate of the solution.

If the smell persists, treat any of the heavily soiled areas with another round of enzymatic cleaner. This will make your floors much easier to clean in the future, will seal any pores and usually looks more attractive. How do I treat a floor made of clay brick that is not cemented together? Mark Spelman is a General Contractor in Texas. He has been a construction professional since 1987. For this kind of floor that isn’t cemented you will need to add sand at all the joints. How long should I let my concrete floor dry before I lay plank flooring on it? Usually about one day, but you should use a moisture meter if you want to be sure. What are some names of enzymatic cleaners I can easily find in the store?