Sometimes when we are performing a urine removal job we have to go the extra step of pulling the carpet and pad back to target severe urine damage. The tan spot on the floor next to the wall is the urine damage. In Tampa FL our homes are built on poured concrete slabs. Concrete is porous and can easily absorb urine making it difficult to treat it from the surface.
On this particular job, the new homeowners were aware that one room had urine deposits in the carpet, so they replaced the carpet and pad. The urine odor did not leave with the carpet and pad because the urine had penetrated the concrete subfloor. The good news is that we were able to pull back the carpet and pad and treat the urine directly. Treating the urine directly made sure we solved the problem without having to get the new carpet wet.
Most of the time we can treat urine from the surface but urine damage can be sneaky and drastic measures may need to be taken to ensure a successful urine removal job.