Pet urine stains in terrazzo under old carpet

Pet urine stains on terrazzo usually show up as dark, irregular blotches when old carpet comes up, often in corners and beside doors. Grinding at $5 to $9 per square foot removes the shallow part, and a poultice at $150 to $600 per area lightens much of what is left. Some old, repeated stains stay as a faint shadow. We will tell you which ones from the photos before you commit.

Check this first

1. Map the stains. Pull the carpet and pad and mark each dark area with tape. Pet stains cluster: corners, beside doors, near where a crate or bed sat.
2. Note the color. Yellow-brown blotches are typical. Dark brown or black, especially with a hard edge, usually means years of repeated accidents in one spot.
3. Sniff. If the smell is strong with the carpet out, urine has gone into the cement. That spot will need more than the grind.
4. Wipe with water. Nothing comes off: the stain is in the floor, not on it.
5. Check the pad. If the pad over the stain had rotted or stuck to the floor, the exposure was long.

What is behind it

Why some come out and some do not

Terrazzo is marble chips in a Portland cement binder. The marble chips are dense and resist staining. The cement between them is more porous, and that is where urine goes. A stain that sat for a few months stays near the surface and grinds off. A stain renewed for ten years in the same corner can discolor the cement well below the depth any sensible grind will take off a half-inch topping.

That is the honest limit, and the NTMA says it plainly in its restoration specification: “All staining in existing terrazzo may not be possible to remove.” What we promise is the effort and the truth about the result, not a clean slate.

How we treat it

1. Enzyme pre-clean on strong-smelling spots once the carpet is out, to break down what is left.
2. Metal-bond grinding with the rest of the floor removes the top skin and the shallow staining.
3. Look again. After the grind we can see exactly what is left.
4. Poultice on each remaining spot: a paste chosen for organic stains, left to dry so it draws staining up out of the cement, then removed. Stubborn spots get a second round.
5. Hone, polish and seal with the rest of the floor.

We do not bleach terrazzo. The NTMA’s care guide lists bleach, vinegar and ammonia among products not to use, and bleach on a urine stain can leave a pale, etched patch instead. Details on the stain and rust removal page.

Why so many turn up in Tampa houses

Many of Hillsborough’s terrazzo houses have spent decades under carpet. In our pull of county records, 124 of the 464 houses built between 1950 and 1972 list carpet as their flooring, more than list terrazzo. Carpet over a cement floor in a house with pets is exactly where these stains come from, so if a house you own or are buying had dogs or cats on carpet, expect to find some when the carpet comes up.

When to call

Once the carpet is out. Send photos of each stained area with a coin for scale, a wide shot of the room and the square footage. We will sort the stains into “will grind out,” “will lighten a lot” and “may stay visible,” and price from the pricing page. If stains are the only issue on an already polished floor, the repair visit estimator adds them up.