Terrazzo: repair, polishing and getting the shine back.
Terrazzo lasts for decades and then looks tired all at once: grey lanes, a yellowed coating, chips holding dirt, a hairline crack across the foyer. Almost all of it comes back, because the material underneath is still there.
Terrazzo is chips of marble, granite, quartz or glass set in a cement or resin binder, ground flat and polished. Its look depends entirely on how the surface is cleaned, refined and protected, and its two binders behave differently: cement etches under acid like marble does, resin has other tolerances but hates abrasives and harsh chemicals just the same.
Why it dulls
Fine scratches from grit and traffic scatter light, so the floor looks flat or grey even when clean. Mop haze and detergent residue cloud it. Waxes and acrylic "mop and glow" finishes yellow, trap dirt, peel at the lane edges and hide the floor's real condition. Acidic cleaners etch the cement binder unevenly, so the floor looks patchy. Chips at doorways and steps hold dirt; cracks collect it and show more each year.
Clean, and strip the coatings
The floor is deep cleaned with products that do not attack the binder or dull the aggregate. Old coatings are stripped with a remover tested on a small area first, because the wrong stripper blotches the binder or softens surrounding materials, and rinsed thoroughly. This stage regularly reveals that the terrazzo underneath is in better shape than expected.
Chips and cracks
Small chips are filled with a colour-matched resin or cementitious material, with aggregate incorporated where practical so the repair carries the pattern rather than closing the hole with a flat colour. Stable hairline cracks are filled and blended. A crack that follows a joint or substrate movement can reopen after any repair, and no honest contractor promises otherwise; the surface is still improved, and the movement is named. Edges at steps, doorways and transitions are rebuilt to profile, because they take the impacts and show first.
Grinding, honing, polishing
Grinding with coarse diamonds is for lippage, deep scratches, stubborn coatings and uneven old repairs. It removes a controlled amount of material and is not used because it sounds thorough; a lightly worn floor goes straight to honing and keeps its surface. Honing with progressively finer diamonds removes the scratch pattern of each stage and gives an even base. Polishing then takes the floor to the sheen the room wants: high gloss makes the aggregate colours rich in a lobby or a living room; satin is more practical in a busy corridor or near a wet area, because it hides footprints and fine scratches. The result should be even across the whole floor, not glossy in patches, with no swirl marks and no plastic film.
Sealing
A penetrating sealer slows water, oil and staining without a film; on some commercial floors a compatible guard system is the right call for maintenance and sheen. Either way sealing is protection, not shine, and entry mats, felt under furniture and a maintenance schedule matched to the traffic do the rest.
What not to do
No vinegar, lemon, bleach, ammonia or acidic bathroom products; cement-based terrazzo etches permanently. No powders or abrasive pads chasing a quick shine; they widen the dull patch. No rental polisher with the wrong pad; swirl marks and uneven sheen are harder to fix than dullness. Steam only if the floor's installer or restorer has confirmed it for that binder. Daily: grit swept before mopping, a neutral cleaner, clean water often, spills wiped.
Replacing terrazzo is disruptive and expensive, particularly in a strata building or a shopfront. Where the base is sound, which is nearly always, a proper restoration returns the floor and keeps the character that made it worth laying.
On this site
Related questions.
Some tiles sit higher than others. Can that be fixed?
Yes. That is lippage, where adjacent tiles were laid at slightly different heights, and it is the main reason to grind a floor rather than just polish it. Grinding takes the whole floor down to one flat plane, removing the high edges so the surface reads as a single sheet of stone rather than a grid of tiles. It is more work than polishing alone and it produces the most dramatic result, because a flat floor reflects as one continuous surface. It also removes the edges that catch dirt and feet. Once ground, the floor is honed and polished as normal. How much can come off depends on the tile. A thick stone tile takes grinding easily, while a thin tile, or one laid over a floor that flexes, has less to give and is assessed first. Grinding is also the point where a floor is made properly flat for the first time, since most lippage is set at installation rather than appearing later.
Do you do commercial work, foyers and strata?
Yes, where the job suits the way we work. Foyer floors, reception benches and common-area bathrooms are the same stone and the same method as a home, at larger scale and usually after hours. Strata and building managers get a written scope, a schedule that works around residents, and the insurance certificate before we start.