Laying it wet, laying it as panels, coating an existing floor, and why the substrate is half the specification.
20 questions in this harvest fall under this subject. 9 answered so far.
It depends entirely on the process, and this is where the five types separate most sharply. Precast is dry-laid and jointed. Cement-bound is laid wet over the substrate and ground back to it. Epoxy is a coating. Poured terrazzo is placed in layers over a divider grid and ground twice. Porcelain is a tile and follows tile rules.
Sometimes, and the sand-cushion system is never one of the answers. It needs three inches of build-up, and a finished floor has no three inches to give. What is available is epoxy at three-eighths inch, precast tile, or a coating — and the one thing you must establish first is whether the slab under you has cracks.
A cement-bound floor is cold, because it is a dense slab laid on the structure with nothing insulating between it and the slab. Underfloor heating changes that: a thin resin terrazzo conducts heat better than a thick cement one, because there is less mass between the pipe and the room. The heat source is the fix, not the finish.
Like any hard floor, it transmits impact sound rather than absorbing it, and the rating it ends up with belongs to the assembly rather than to the terrazzo. Impact Insulation Class is defined by ASTM E989 and measured to ASTM E492; IIC 50 is the figure most codes ask for, and a bare hard floor on a slab does not reach it.
At least three passes on a standard cement-bound floor, and on a high-performance floor the count is set by design rather than by a rule. The pass count is in the code; the grit sequence is in practice, and it steps up in stages: a coarse cut to expose the aggregate, a transition pass, a grout coat, then progressive refinement.
Flat, clean, and strong enough: the binding layer under a cement-bound terrazzo is not less than M10 with a consistency of 30 to 35 millimetres. Where there is no built-up system and the terrazzo is bonded straight down, the slab has to be flat enough that the finished floor hits its 3 millimetre tolerance after the topping is added — which means the slab is held to a tighter number than a tile installation would need.
An epoxy floor is walked on within a day: NTMA-based specifications call for a minimum of 24 hours at 25 degrees Celsius before grinding even begins. A cement-bound floor has no comparable published figure, because curing time belongs to the binder and the conditions rather than to terrazzo, so ask the installer for the time on their product.
It works over a sound, clean, level floor, and it fails over a cracked one for the same reason every cement-bound terrazzo fails over a cracked slab: the floor is ground together with what is under it. There is no thick system available to hide behind — a sand cushion needs three inches and a finished floor has none to give — so the substrate is the whole risk.
Two requirements and they are not the same one. The tread wants grip, so it takes a honed or textured finish rather than a polish — a polished terrazzo tread is a slippery stair. The riser and the fixing want a mechanical anchor through the panel, because a tread that is only bonded will work loose at the nosing under load.
These are the phrasings people typed, not headings we invented. Where one has an answer the link is live; where it does not it is printed plain, and that is deliberate — a printed question with nothing behind it is an honest promise, and hiding it is not.
Read the answer first — it says which of these to specify and why.
Ordered by how many questions each one holds.