Preparation is where most of the money goes
Diamond grinding a slab takes hours, consumes tooling, and requires equipment worth tens of thousands of dollars. Acid etching takes twenty minutes and costs the price of a jug of muriatic acid. That single substitution is the largest saving available to a contractor and the largest cause of coating failure, which is why it is the first thing to ask about.
Full broadcast versus partial
Both are sold as "flake systems". A full broadcast throws chip until the floor rejects more, at roughly 0.5-0.8 lbs per square foot. A partial broadcast covers 40-60% and uses about a third of the material. It looks acceptable on handover day and shows its age within a year or two as the exposed base colour wears differently from the chip.
Solids content
A 100% solids epoxy leaves behind everything that was applied. A 45% solids product loses more than half its volume to evaporation, leaving a film a fraction as thick. Product cost per pail looks similar on an invoice; the finished floor is not remotely comparable.
The email that settles it
Send every contractor the same four questions in writing: how do you prepare the slab and to what profile, do you moisture test before quoting, is the flake broadcast full or partial, and what is the total film thickness in mils. A good contractor answers each in a sentence. The gap in the replies will explain the gap in the prices.
Want this answered for your slab?
Free site visit with a moisture reading, then a written fixed price. Across the BC Interior.