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Answers

Terrazzo or microcement for a floor?

They are close on thickness and far apart on what happens when the floor is damaged. Microcement is a thin coating that cannot be re-ground or patched to a match. Terrazzo is a graded aggregate floor that can. If the floor will be handled hard, that difference is worth more than the two surfaces looking similar on the day.
Six terrazzo processes, drawn to one scaleEach column shows the layers of one terrazzo process. Precast and cement-bound are thick; epoxy is thin; porcelain is a fired body. Dimensions are published ranges, not our measured figures.substratePrecast20 mmsubstrateCement-based12 mmsubstrateEpoxy5 mmsubstratePoured10 mmsubstrateLiquid3 mmsubstratePorcelain9 mmSections drawn to one scale from published ranges. Our measured figures are listed separately.
The six processes drawn to one scale. Layer thicknesses are published ranges.

The figures, and where each one comes from

Terrazzo Microcement
What carries the wear the aggregate at the surface the coating itself
A local repair patch and re-ground to match a patch that shows
Re-groundable yes, cement-bound and precast no
Typical build-up 1/2 in topping, or a thin system a coating over a base
Variation between batches controlled by the mix a colour difference that has to be matched

Why the processes are not interchangeable

Microcement and thin terrazzo occupy the same slot in a renovation — both go over an existing floor without a three-inch build-up — and they are chosen on the same basis. Where they part company is the repair. A microcement floor is a coating, so a damaged area is a patch, and matching a patch to a hand-trowelled surface is a matter of skill rather than of chemistry. A terrazzo floor carries the stone through its thickness, so grinding a repair back into the surrounding floor is a process that leaves no obvious seam. Neither is the better floor; they are different answers to "how much do I expect this to be damaged".

What these figures are, and what they are not

⛔ No thickness figure for microcement appears here, because we could not trace one to a standard and the numbers in trade copy are not reproduced. The terrazzo build-ups are from the NTMA systems table. ⛔ We do not supply microcement and nothing here is a comparison of two products we both sell.

If you are specifying this

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