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Answers

Can terrazzo be made thinner, and what do you give up?

Yes, down to 8 millimetres, and the constraint that decides how thin is arithmetic rather than marketing: the largest chip may not exceed two thirds of the topping thickness. At 8 millimetres that caps the aggregate at about 5. What you trade is the depth of the wearing surface, not the material.
Chip size against topping thicknessA horizontal scale in millimetres. For each topping thickness from 8 to 18 millimetres, a bar shows the topping and a second bar shows the largest stone chip permitted, which is two thirds of the thickness. Derived from JC/T 507-2022 clause 5.3.0481216208 mm5.3 mmthe band we supply10 mm6.7 mm12 mm8 mm15 mm10 mm18 mm12 mmTopping thickness (solid) against the largest chip permitted (accent), on one millimetre scale.Chip ceiling is two thirds of the thickness (JC/T 507-2022 cl.5.3).Topping range from GB 50209-2010 cl.5.4.1; the arithmetic is ours.
Chip size against topping thickness, on one millimetre scale. The chip ceiling is two thirds of the thickness, from JC/T 507-2022 clause 5.3; the arithmetic on the thicknesses is ours.

The figures, and where each one comes from

Topping Chip ceiling What it means
8 mm about 5 mm fine aggregate only, light duty or over an existing floor
10 mm about 6.5 mm fine to medium
12 mm about 8 mm medium aggregate, the practical limit for a normal floor
15 mm about 10 mm medium to large
18 mm about 12 mm large aggregate

Why the processes are not interchangeable

The reason the aggregate cannot stay large in a thin topping is that the chips sit in the wearing surface rather than below it. Once a chip is within a couple of millimetres of the face, the first grinding pass reaches it, and a large chip reached early leaves a pocket rather than a flat surface. So a thin topping is not a cheaper thick topping, it is a different product with a different look: fine aggregate, tight surface, and less reserve to re-ground later. That is the honest trade, and it is why we quote the 8 millimetre band against a use and not as a specification in itself.

What these figures are, and what they are not

The two-thirds relationship is JC/T 507-2022 clause 5.3. The millimetre chip ceilings in the table are our arithmetic from it. ⛔ We have not measured a panel we have supplied at 8 millimetres and we do not publish a measured figure for the chip size in any panel we have made. A buyer specifying this band should ask us what we hold; if the answer is nothing, we will say so.

Measured data sheets and test reports

If you are specifying this

These are the forms we actually supply for this question, with production photographs where we have them:

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