How to plan a polished concrete floor, starting with the slab you have

What should you find out about the slab before calling anyone?

Start by pulling back a corner of carpet or lifting one tile in the least visible spot of each room you want finished. You are looking for four things: the color and texture of the bare concrete, any adhesive or paint residue, cracks and how wide they are, and patches or trenches where the slab was cut and refilled. Photograph each patch with a tape measure in frame. Most owners have a slab to check: our analysis of the federal government's 2024 household survey found 32.4% of homes sit over a slab and 29.5% over a basement, and 41.1% of basement homes report the basement unfinished.

Also note the slab's age if you know it, whether the room has ever flooded or felt damp, and whether the floor slopes noticeably. Age matters because very new concrete may not be cured enough to polish evenly, and older slabs often carry layers of history. Moisture matters less for polishing than for coatings, since polished concrete has no film to blister, but it still affects dyes, guards and any leveling compound. Slope matters because grinding follows the surface; it does not flatten a floor on its own.

• Photograph residue, cracks and patches with a tape measure for scale.
• Note any history of water, efflorescence or a musty smell.
• Roll a ball or use a level to find obvious low spots.
• Record the room sizes; small rooms price differently from open plans.

How much variation can you live with in the finished floor?

This is the decision owners most often skip, and it is the one that causes the most regret. Every existing slab shows something after polishing: a lighter patch where a wall once stood, a line where plumbing was trenched, tack-strip nail holes along the walls, darker areas where oil or water sat for years. A contractor can fill and blend many of these, but blended is not invisible. Decide now whether you want character or uniformity, because the answer may point you away from polishing entirely.

Owners who want a perfectly even color usually belong on a coating or an overlay, not a polish. Owners who like the idea of the house's history showing tend to be happiest with polished concrete. Most people sit in between, and for them the mock-up described below is essential. It is worth reading how others answered the poll on patches and variation before deciding, since the spread of answers shows how differently people react to the same floor.

How do you choose a sheen level and aggregate exposure?

The Concrete Polishing Council defines four appearance levels by how sharply the floor reflects an image, from DOI 0–9 to 70+ on its Distinctness-of-Image scale. Level 2, satin or honed, hides scuffs and dust and suits most houses. Level 3 gives a clear reflection. Level 4 is the mirror look seen in showrooms, and it takes more passes and more upkeep to keep. Pick the lowest level that gives you the look you want; each step up adds grinding and polishing work, which is why Angi's July 2026 guide prices matte at $2–$6/square foot, semigloss at $3–$8/square foot and high gloss at $8–$15/square foot.

Exposure is the second axis. The Council's chart describes cream, salt-and-pepper and coarse-aggregate surfaces at 85–95% / 80–90% coverage of the intended material. Cream grinds the least and shows the most trowel marks and color variation. Salt-and-pepper exposes fine sand and small stones and often hides patches better. Full aggregate requires the deepest cut and can reveal voids and uneven stone. The honed versus high-gloss comparison covers the sheen trade-off in detail.

Why insist on a mock-up, and where should it go?

A mock-up is a small area ground, densified and polished to the proposed specification on your actual slab. It is the only way to see how your concrete responds, and the Concrete Polishing Council's exposure chart itself recommends one. Ask for it in the most difficult part of the floor: near a patch, across a trench line, or where the old flooring adhesive was thickest. A mock-up placed in the cleanest corner tells you very little.

Agree in writing what the mock-up represents. It should use the same tooling sequence, densifier and final grit as the full job, and it becomes the reference for approving the finished floor. Some contractors charge for it and credit the cost against the contract; others include it. Either is reasonable. What is not reasonable is a contractor who will not produce one at all on an existing slab with visible repairs, since that pushes all of the appearance risk onto you.

What should a one-page brief to contractors include?

A written brief keeps every bid describing the same job. It does not need to be technical; it needs to be complete. List each room with its size and current covering, attach the patch photos, state the appearance level and exposure class you want, and say whether you want color, a guard or both. Mention furniture that cannot move, pets, working hours and whether anyone will be home. Send the same brief to everyone.

Close the brief with the things you expect each proposal to state: number of grinding and polishing passes with grits, the densifier product, how cracks and joints will be treated, dust control method, mock-up terms, final gloss or DOI readings, and what happens if the finished floor does not match the mock-up. The estimate request form asks for most of this, so you can paste the brief into it directly.

• Rooms, sizes and current coverings
• Target CPC level and exposure class
• Color, guard and joint treatment wanted
• Access limits, occupancy and working hours
• Items every proposal must state in writing

How long does the work take, and what has to leave the room?

HomeGuide puts a residential polish at 2–4 days for floors up to about 2,000 square feet, with repairs, leveling and color adding days. Removal of old flooring comes first and can take as long as the polish itself, especially with glued tile or thick mastic. Plan for the whole room to be empty, including baseboards if the contractor wants to grind right to the wall. Built-in cabinets stay, but the edges around them are hand-ground and may look slightly different.

Polishing is walkable almost immediately because there is no film to cure, which is one of its advantages over coatings. Dyes and guards add short drying windows. The real disruption is noise and, with dry grinding, dust. Ask how the contractor controls dust, whether you need to seal off HVAC returns, and whether it is realistic to stay in the house. For a basement or single room, most families do; for a whole ground floor, many plan a few nights elsewhere.

When is a concrete finish the wrong plan for your floor?

Some slabs should not be polished. A floor with widespread oil saturation, large areas of patching, a crumbling surface that fails a scratch test, or significant unevenness may be a better candidate for an overlay, a coating or conventional flooring. Very thin toppings over wood framing can crack under grinding. Owners in rooms that need warmth underfoot or sound absorption should also weigh whether a hard floor suits the space at all.

There is no shame in stopping at the assessment. A proper grinding and leveling visit tells you more about your slab in an hour than any amount of reading, and the cost of that visit is small compared with a floor you dislike. If the answer is a sealed ground floor rather than a full polish, the grind-and-seal comparison explains when that cheaper route makes more sense.