What is concrete grinding?

How concrete grinding works

Diamond segments held in a metal or resin bond are pressed against the slab and spun. The diamonds cut the concrete; the bond wears away at a controlled rate to keep exposing fresh diamond. Coarse segments cut fast and leave deep scratches, finer segments cut slowly and leave finer ones, so grinding is worked as a sequence — each pass removing the scratch pattern left by the pass before it.

Skipping steps in that sequence is the classic error. The scratches from a coarse pass do not disappear because a fine pass went over them; they sit under the finish and show up the moment light hits the floor at an angle. A floor ground properly at every grit takes longer and looks right.

Grinding, honing and polishing are not the same thing

Grinding is the cutting stage: metal-bond tooling removing material. Honing is the refining stage that follows. Polishing is the final closing of the surface, and on a mechanically polished concrete floor it is done with fine resin tooling, usually with a densifier applied to harden the slab first. Once that floor is finished and in service, keeping it is a maintenance job, not a grinding job — a rotary scrubber and the right pad, run regularly.

Dust is the serious part

Dry grinding concrete generates respirable crystalline silica, which is a regulated workplace health hazard in Australia and a genuine long-term risk to the operator, not a nuisance. Grinding is therefore done either wet, so the slurry binds the dust, or dry with a shrouded head connected to a dust extractor rated for the job. Both methods carry obligations under work health and safety law — check the current requirements in your jurisdiction before planning the work.

When it matters

Grind when material has to come off the slab. Adhesive residue from lifted vinyl, an old epoxy that is failing, trowel ridges and slab high spots, or a floor that has to be opened up so a new coating can key into it — none of those are fixable by cleaning, however aggressive. Grinding is also the entry point for polished concrete, where the aggregate has to be cut into before there is anything to polish.

Do not grind a floor that is merely dirty or dull. Ground-in soil comes off with a rotary scrubber and the right pad and chemical; a coating that is sound but tired is usually a stripping and recoating job. Grinding is irreversible — every pass takes slab thickness that is not coming back, and on a thin topping or over in-slab services it is a decision to take carefully rather than a default.

POLIVAC does not build concrete grinders. What the range covers is the floor once it is finished: the C27 and C27 GEN2 rotary scrubbers are specified for polished concrete among other hard surfaces, and that regular maintenance is what determines whether a ground-and-polished floor still looks like one in five years. The most common false economy on these floors is paying for the grind and then maintaining it with a mop.