Yes, most worn polished concrete can be refinished without cutting the floor back to aggregate. The question is not whether it can be done but how deep the damage goes, because a top-two-step refinish fixes wear, not defects.

Decide by depth, not by appearance

Condition	Depth	Approach
Dull traffic lanes, light scuffs	Film only	Burnish and re-guard, or 1 resin step
Visible scratch pattern, etched spots	0.1-0.3 mm	Two-step top refinish (e.g. 200 then 400 resin)
Aggregate exposed unevenly, pits	0.5 mm+	Partial resurface with metal bond, then re-hone
Delamination, hollow spots, curl	Structural	Repair slab first; polishing will not fix it

What a top refinish actually does

A two-step refinish re-cuts the top resin scratch pattern and restores the clarity that makes a polished floor read as gloss. It does not restore cream colour if the cream layer was worn through, and it will not close a pit. Expect 70-90% visual recovery on a floor that was only worn, and 40-60% on one that was abused.

Sequence

1. Clean and strip any guard or sealer with a neutral or slightly alkaline cleaner and a red pad.
2. Identify the last grit the floor was finished at. Start one step coarser, not two, or you cut through the cream.
3. Run the two resin steps with a planetary or three-head machine, 4-6 passes per step, 30-40% overlap.
4. Re-densify only if the surface absorbs water quickly. Over-densifying a refined floor creates the same haze problems as a first pass.
5. Finish with the guard or burnish the client wants, and take gloss readings at the same angle as the original handover.

Cost comparison

A top refinish typically runs at 30-50% of a full resurface on the same area, because it skips metal bond and the heavy hone steps. The trade-off is a shorter service life: 2-4 years on commercial traffic versus 8-10 for a full resurface done properly.

When not to refinish

• The floor has visible aggregate pull-out or pitting wider than 5 mm.
• Gloss readings vary more than 15 units across a 3 m straightedge with no pattern.
• The slab has been coated with a curing compound that was never removed.
• The client expects a like-new floor; a refinish is a restoration, not a rebuild.

Pick the starting grit from what is visible

The grit you start at is set by the deepest defect you can see, not by the grit the floor was finished at. Starting one step too coarse exposes cream you did not intend to cut and turns a refinish into a resurface; starting one step too fine polishes over the scratch that caused the call-out.

What is visible	Typical depth	Start at	Finish at
Uniform dull lanes, no scratch pattern	Film only	Burnish, no cutting	Guard or 800 resin
Circular scratch haze from a swing machine	0.05-0.1 mm	One step coarser than the finish grit	Original finish grit
Straight scratches from dragged loads	0.1-0.2 mm	200 resin	400-800 resin
Etched rings from acid or citrus cleaner	0.1-0.3 mm	100-200 resin	400 resin plus re-densify
Pits and pulled aggregate	0.5 mm+	Metal bond, then hone	Full sequence

Check the call by cutting a 1 m test patch before pricing the whole floor. A patch that comes up in two passes confirms the estimate; a patch that needs a third pass means the damage is deeper than the photograph suggested, and the quote should change before the crew mobilises.

Machine setup and pass counts

• Use a machine heavy enough that the heads stay in contact: below roughly 150 kg on a 500 mm head, the tool rides over the cream instead of cutting it.
• Planetary or three-head machines give a flatter result than a single-head swing machine, which is what a refinish is judged on.
• Run 4-6 passes per grit at 30-40% overlap, at a walking speed slow enough that the ammeter stays in the working band.
• Keep the floor damp but never wet: water is a lubricant and a temperature control, not a flushing agent.
• Extract slurry between grits. Carrying slurry from 200 into 400 loads the finer tool and produces the haze the customer complained about in the first place.
• Change the tool when it stops cutting, not when it looks worn. A glazed resin pad polishes and burnishes without removing depth.

Judge the result after 24 hours, under the same light and angle as the original handover, and take gloss readings at three fixed points. A floor that looks right under a torch at 6 pm and wrong at 9 am the next day was not finished; it was still wet.

Selling the top refinish honestly

The hardest part of a top refinish is not the polishing, it is the expectation. A floor that has been refinished twice looks better than it did last month and not as good as it did on day one, and the client should hear that before the price is agreed.

• Say what is being restored: the film, the clean surface and the sheen. Not the aggregate, not the depth of cut, not the original flatness.
• Show a test patch and let the client see it next to the worn area. Ten minutes of test patch replaces an hour of adjectives.
• Quote per square metre with the number of grit steps included. A price without steps invites the assumption that a full recut was included.
• State the expected service interval. A top refinish on a retail floor typically buys 2-5 years before the next pass, not a decade.
• Offer the full recut as an alternative with its own price, so the client chooses depth rather than accepting whatever arrives.

Handled this way, the top refinish is a maintenance product with a clear interval. Handled the other way, it is a disappointment that gets blamed on the polish.

Document the readings before and after. A refinish sold as a restoration with numbers attached is defensible; one sold on appearance alone invites a callback.