What Polished Concrete Really Is

A lot of people say “polished concrete” when they mean one of three completely different things. Getting this straight is the single most important step in the course, because it decides everything downstream — machine, diamonds, chemistry and price.

The three things people mean

1. Polished concrete (the real thing). The existing slab is ground down with progressively finer diamond segments until the surface is dense, hard and reflective. A densifier (typically lithium or potassium silicate) is applied to harden the surface and boost the shine. There is no coating layer — the floor is the concrete, made better.

2. Ground (or honed) concrete. The slab is ground to a matte, uniform finish but not taken all the way to a shine. Cheaper, faster, and the most common “industrial” look. No densifier needed, though it’s often applied.

3. Sealed concrete. A film-forming sealer is applied to a cleaned slab. This is a coating, not a polish. It protects against water and stains but wears out and needs reapplication. If a spec says “polished” but the method is a sealer, you’re looking at a different product entirely.

Why it matters

Polished concrete is among the most durable finishes you can put on a slab — it can outlast the building. There’s nothing to peel, flake or re-coat. Maintenance is essentially sweeping and occasional wet-mopping, with a refresh of densifier every few years in heavy traffic.

The trade-off: it demands a decent slab. Polishing a dusty, weak, heavily-cracked or contaminated slab will show every defect, because you’re exposing the material, not hiding it. On a light-traffic residential floor, the cost of true polishing often isn’t justified — sealing or honing gets 80% of the look for 40% of the cost.

A quick decision rule

• High traffic, industrial, wants a hard durable floor → polish + densify
• Industrial, wants the look, budget-conscious → honed
• Light traffic, wants stain resistance → sealed

Checklist: Before you quote any “polished concrete” job, confirm with the client which of the three they actually want, and inspect the slab. If the slab is bad, tell them honestly — a polished bad slab is an expensive way to show off its flaws.

Key takeaways

• Polished concrete is the slab itself, ground and densified — not a coating on top.
• The shine comes from exposing and closing the aggregate, not from wax or sealant.
• It wins on durability and low maintenance; it loses where the slab is poor or traffic is light.