THE PRACTICAL
CONCRETE GRINDING GUIDE

01 / WHAT CONCRETE GRINDING ACTUALLY DOES

Grinding uses diamond segments held in a metal bond, spun under weight, to cut the top of a slab away. Two things matter: the diamonds do the cutting, and the bond controls how quickly those diamonds are exposed and released. Get the bond wrong and the tooling either glazes over and stops cutting, or wears out in a morning.

You grind for three reasons: to remove something (coating, glue, levelling compound, high spots), to open the surface so a coating can key into it, or to refine the surface towards a polished or honed finish.

02 / READ THE SLAB FIRST

Before you choose tooling, work out how hard the concrete is. Quick field cues:

• Hard slab — burnished or power-trowelled warehouse floors, tight dense surface, a nail or screwdriver barely scratches it, very little dust when you scratch it.
• Medium slab — most residential and commercial floors, a screwdriver leaves a mark with moderate pressure.
• Soft or abrasive slab — exterior slabs, older or weathered concrete, driveways and paths, screws scratch it easily and it dusts up quickly.

Always grind a test patch in a corner before committing to a bond for the whole floor.

03 / BOND SELECTION IS BACKWARDS (ON PURPOSE)

The rule that catches people out: hard concrete needs a soft bond, soft concrete needs a hard bond.

• Soft bond → hard, dense, burnished concrete. The bond wears away fast enough to keep fresh diamond exposed.
• Medium bond → medium concrete. The safe starting point when you genuinely don't know the slab.
• Hard bond → soft, abrasive, exterior concrete. The abrasive slab does the wearing, so the bond has to resist it.

Symptoms of the wrong choice: the tool stops cutting and the floor polishes up (bond too hard) or the segments disappear in a session (bond too soft).

Not sure? Use the bond selector on the storefront, or describe the job to the AI tooling advisor and it will pick the bond, grit and fitting for you.

04 / CHOOSING GRIT

Grit is about how much you need to take off and what you're leaving behind, not how fast you want to go.

• 16# / 30# — heavy removal: high spots, levelling compound, aggressive opening of the slab.
• 60# — the workhorse grit for surface prep. Removes the scratch left by metals below it and leaves a strong mechanical key.
• 80# / 120# — refining, blending scratch patterns, prepping for thinner coatings and moving towards a honed look.

Never skip more than one step. Jumping from 16# straight to 120# leaves deep scratches you'll see through the coating.

05 / WHAT GRIT BEFORE EPOXY?

For most epoxy and polyurethane systems on Australian slabs, grind with metal-bond diamonds to around 30# then 60#. That gives an open, consistently scratched surface — roughly the profile coating manufacturers ask for — without going so fine that the surface closes back up.

Check the coating data sheet: some high-build systems want a coarser profile, and thin sealers want finer. Vacuum thoroughly and make sure the slab is dry before you coat.

06 / REMOVING COATINGS, GLUE AND MEMBRANES

Soft, gummy materials — carpet glue, vinyl adhesive, membranes, thick soft epoxy — clog diamond tooling. Use PCD tooling to strip them first, then follow with diamonds to clean up the scratch:

• 1/4 PCD — thin or soft residues where you want control and a light scratch.
• 1/2 PCD — the general-purpose choice for stubborn coatings and glue.
• Full PCD — hard, brittle, thick coatings you need to break and lift.
• PCD + diamond segment — strips and refines in one pass, which keeps the scratch under control.

Follow up with 30#/60# metal diamonds to remove the PCD scratch before coating. For edges, corners and small patches, use cup wheels and multi-tool blades on an angle grinder.

07 / MACHINE AND FITTING

Machine weight and head speed change how a bond behaves — a heavier machine effectively acts like a softer bond. Match the shoe fitting to your plate system: Husqvarna Redi-Lock, Lavina quick-change, magnetic plates, or universal bolt-on. Get this wrong and the tooling won't mount at all. See machine compatibility if you're unsure which one your grinder takes.

08 / DUST AND SILICA

Grinding concrete generates respirable crystalline silica. Work with proper dust extraction on the machine, use a suitable HEPA vacuum, wear appropriate respiratory protection and follow your state's silica work requirements. Wet grinding controls dust but creates slurry you need to manage.

NEXT STEPS

Ready to tool up? Browse GRINDX diamond tooling, or apply for a trade account for professional pricing and direct support.