Flooring boxes carry a lot of numbers and most of them matter. Here are the ones worth checking before you pay.
AC rating (laminate)
An abrasion class from AC1 to AC5. AC3 is the usual floor for a home; AC4 and AC5 are rated for commercial traffic. Anything below AC3 belongs on a wall or in a very light-use room.
Wear layer in mils (vinyl)
The clear layer over the printed pattern. 12 mil is a sensible residential default, 20 mil and above is commercial. This is the single best predictor of how a vinyl floor ages.
Wear layer in millimetres (engineered hardwood)
Confusingly, a different thing with a similar name. Here it is the thickness of the real timber on top. Roughly 2 mm or less means it cannot be sanded; 3 mm and up allows at least one refinish.
PEI rating (tile)
A hardness class from 1 to 5. PEI 1 and 2 are wall tiles. PEI 3 suits most residential floors, 4 handles heavy traffic, 5 is commercial. Putting a wall tile on a floor is a common and expensive mistake.
Slip resistance (tile)
Usually quoted as a coefficient of friction. It matters anywhere the floor gets wet — bathrooms, entries, anywhere tracked-in rain lands. A beautiful polished tile in an entry is a hazard.
Dye lot or batch number
Not a performance figure, but the one that causes the most grief. Material from different batches can differ slightly in shade. Buy the whole job, plus the spare, from one batch — and check the numbers match across the pallet before it leaves.
We will read them with you
Bring the room and the use case to the counter and we will pull the spec sheets. It is a five-minute conversation that saves a floor.