In severe odor situations (*strong* cat urine odor), throw out the carpet,
pad, tack strip.

Urine turns *alkaline* from an acid in a matter of a few days after being
deposited. Therefore, you use an *acid* to clean...not an akaline, like
bleach, or detergents. I use Unsmoke Pipe and Porcelain Cleaner, an acid
detergent, used to clean bathroom fixtures. Vinegar would work; I would mix
50/50 with water.

[You smell *ammonia* in dried urine...ammonia is probably the strongest
alkaline cleaner in a home.]

If the floors are wood, lightly sand, sweep/vacuum, scrub with your acid
solution, extract/mop. Let dry.

If the floors are cement, sweep/vacuum, scrub with your acid solution,
extract/mop. Let dry.

Spray the solution on with a pump garden sprayer, and agitate with a push
broom. Or mop it on. Use a wet vac to extract, or mop.

Apply a solvent based acryllic sealer for cement. I use Neutralizer's
"Neutral-P-Seal". *Any* solvent based acryllic cement sealer will work. The
above product also works on wood subfloors. Thompson's Water Seal is
*specifically* not recommended.

We use BINZ (favorite) or KILZ, or any alcohol based shellac on walls and
wood. Same process; clean with acid, dry, seal.

The idea is simple: you cannot remove dried urine from *porous* surfaces
like wood and cement. You must *seal* the unremovable urine in the
contaminated surfaces. It must be sealed from *exposure* to heat and
moisture. If warm, moist air does not contact the dried urine crystals, you
will NOT smell the urine.

If you do not seal, and even when the cat is gone, and carpet is simply
replaced, warm, moist air will make the smell return, and contaminate the
new flooring. *Months*, even *years* later. You *only* smell in the presence
of heat and moisture.

Enzymes can work, but in situations of strong odor, they *never* will. A cat
urinating just 6 ozs per day is 17 gallons of urine per year. Enzymes will
work in single or very infrequent urinations. However, if the smell is
strong, you have a major contamination. If 20% of the surface is
contaminated, 60% of the underlayment is. (Use a blacklight to find; males
urinate on perimeter vertical surfaces, females squat in the center of
rooms, usually.)

On contaminated wood or cement sub-floors, you can put down *hundreds* of
gallons of bleach, detergent, water, enzymes...pick your favorite. You can
extract with a bilge pump after *flooding* the structure, and you will
*never* remove the urine from the billions of holes in these floors.

Wash with an acid after light sanding of wood. Extract and dry. Seal. Done.
Odor *gone*.

Simple.