Granito and Terrazzo: Maintenance, Grinding Hollows and What to Know Before Treatment

Granito and terrazzo: the same material, two names

Granito and terrazzo are often used interchangeably. Both refer to the same type of floor: a composite of cement plaster (or sometimes resin) containing fragments of natural stone, marble, glass or shell. The fragments are scattered into the wet cement layer, pressed in and ground flat after curing.

The difference is tradition and region. In the Netherlands people usually say granito; in Italy and internationally, terrazzo. The material, technique and challenges are the same.

Granito is common in pre-war and post-war homes, schools, hospitals and public buildings. Many of these floors are decades old and, despite neglect, still have a sound base.

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How granito is traditionally made

A terrazzo installer applies a cement-bound mortar layer to the subfloor. Stone fragments are scattered into the still-wet mortar — their size, colour and density determine the final appearance. After curing, the surface is ground until the stone fragments become visible and the whole surface feels flat.

This is where there is a crucial difference from natural-stone finishing.

Dry grinding versus wet grinding

Natural-stone specialists grind with water. The water cools the diamond disc, removes grinding dust and creates an even contact surface. The result is usually uniform.

Terrazzo workers traditionally grind dry. There are historical and practical reasons for this: during installation, the cement-bound floor must be finished quickly, and wet working slows the process. Dry grinding is faster, but it has a consequence that only becomes visible later.

Grinding hollows and undulations

During dry grinding, the machine does not apply equal pressure everywhere. The edge of the grinding disc presses differently from the centre. Some zones receive more passes than others. The result: the surface looks flat, but it contains subtle undulations — microscopic hollows and rises in the surface.

With a matt finish this is barely visible, if at all. The surface feels smooth and looks good.

But as soon as you increase the gloss level, it becomes visible.

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Why higher gloss shows more unevenness

This is the most important thing to know as the owner of a granito floor.

Test it yourself: take a damp cloth and wipe one corner of your granito floor. The wet patch temporarily has more shine than the dry surroundings. In that moment of gloss, you suddenly see irregularities you did not notice when dry: breaks in the reflection, matt spots, slight depressions.

Those are the grinding hollows from the original dry grinding. They were always there — you simply did not see them because the low gloss concealed them.

What this means for treatment:

If you have a granito floor honed or polished, you increase the gloss level. With that higher gloss, the undulations from the original installation become more visible. This is not an error by the contractor. It is a property of the material and the way it was once laid and ground.

Making a granito floor completely even — without any undulation — would mean re-flattening the entire surface with wet diamond grinding. That is possible, but considerably more expensive and intensive than a standard refresh.

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What can you realistically expect?

With honing (satin gloss)

• A beautiful, warm satin sheen
• Colours become more intense
• The floor feels smoother
• Grinding hollows become slightly more visible, but usually not distracting overall
• This is the most commonly chosen option for granito floors

With polishing (high gloss)

• Mirror-like reflection
• Colours at their richest
• Grinding hollows become clearly visible in raking light or when the surface is wet
• Suitable if you accept the character of the floor, including its craft imperfections
• Less suitable if you expect a perfectly even mirror

With flattening + honing/polishing

• The entire surface is re-flattened using wet diamond techniques
• Grinding hollows are largely eliminated
• Considerably more intensive and expensive
• The best result when budget and time allow

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Daily maintenance of granito

Granito is robust. The cement-bound matrix is hard, durable and resistant to most everyday loads. Maintenance is simple if you follow a few rules.

Daily

• Vacuum or sweep dry before wet cleaning. Sand and grit are the main enemies — they create scratches that reduce gloss over time.
• Damp mop with a well-wrung mop and a pH-neutral stone cleaner. Do not flood the floor — granito absorbs moisture through micropores and joints.
• No vinegar, cleaning vinegar or all-purpose cleaner. The cement matrix is sensitive to acidic products. Repeated use of acidic cleaners attacks the binder.

Weekly to monthly

• Check the joints. In granito, joints are often less visible than in tiles, but they do wear. Damaged joints allow moisture under the floor.
• Remove stains immediately. Coffee, wine and oil penetrate if the floor is not impregnated.

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Impregnating granito

Granito has pores — fewer than limestone, more than granite. Without impregnation, liquids soak in and stains form.

When?

• After every grinding or polishing treatment
• If the water test fails: place a drop of water on the floor — if it soaks in, retreatment is needed
• Usually every 1–3 years, depending on use

Which product?

• BioShield or a comparable solvent-free impregnator suitable for cement-bound stone
• No oil-based impregnators — they can discolour lighter stone fragments
• No topcoats or lacquers — they eventually flake

How?

1. Clean the floor thoroughly and let it dry completely (24 hours)
2. Apply the impregnator with a soft brush or cloth
3. Allow 5–10 minutes to penetrate
4. Remove excess product before it dries
5. Allow 24 hours drying time before normal use

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Common problems with granito floors

White bloom (efflorescence)

Salts from the cement layer or subfloor migrate to the surface and form a white haze. This points to moisture problems under the floor. The bloom itself can be removed, but the source — moisture — must be addressed.

Loose fragments

In old granito floors, the cement matrix around individual stone pieces can weaken. The fragments come loose and leave a void. This can be repaired with matching stone adhesive or terrazzo repair mortar, but invisible repair requires skill.

Cracks

Granito does not have joints or movement gaps in the same way as tiled work. Settlement of the building or thermal movement can cause cracks. Small cracks can be repaired cosmetically. Structural cracks point to an underlying problem.

Paint traces and coatings

Many granito floors in old homes were once painted or given a synthetic coating. Removing this without damaging the stone is labour-intensive. Laser cleaning can be a solution.

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Granito versus natural stone: what is the difference?

	Granito/Terrazzo	Natural stone
Composition	Cement + stone fragments (man-made composite)	Solid rock from nature
Hardness	Variable, depending on binder and fragments	Depends on type (marble soft, granite hard)
Acid sensitivity	Moderate — cement matrix is sensitive	Highly variable by stone type
Traditional grinding method	Dry (terrazzo workers)	Wet (natural-stone specialists)
Grinding hollows	Often present because of dry grinding	Less common because of wet technique
Repair	Add mortar + stone fragments	Grinding/polishing or stone adhesive

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When should you call in a specialist?

• The floor is dull and worn but the base is intact → honing + impregnation
• You want maximum gloss and accept that grinding hollows become more visible → polishing + impregnation
• You want the most even result possible → flattening + honing/polishing (discuss expectations beforehand)
• Loose fragments or cracks → repair + treatment — read more about cracks in natural stone
• Old paint or coating removal → laser cleaning or chemical removal — more about laser cleaning natural stone
• White bloom that keeps returning → moisture diagnosis + treatment — read all about white bloom on natural stone

DecoStone treats granito floors and terrazzo with the same precision as solid natural stone. We always discuss in advance what is realistically achievable — including the story about grinding hollows. No surprises afterwards.

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Do you have a granito floor that needs refreshing? We are happy to visit for a no-obligation assessment.

Need help?

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