How To Clean Subfloor From Cat Urine. For fresh urine stains on the subfloor, hydrogen peroxide can help remove the odor. The first step is to treat the subfloor with an enzymatic odor remover.

Mix peroxide & baking soda in the spray bottle; When it comes to cats, they can be a little less attentive of where they’re using the bathroom in comparison to dogs. Now apply the baking soda on the affected or stained area.