100%-solids epoxy
Also called: solids epoxy, two-part epoxy floor coating, epoxy base coat, high-build epoxy, solvent-free epoxy
A two-part epoxy floor coating with no water or solvent carrier, so the film you spread is the film that cures — 10 mils or more in one coat, against 2–3 mils for a water-based kit. $70–$150 a gallon, 30–40 minutes of working time once mixed, and the base coat under most professional garage floors.
Epoxy coatings are sold three ways. Water-based (the hardware-store kits) and solvent-based carry the resin in a liquid that evaporates, leaving a thin film — 2–4 mils dry from a 6–8 mil wet coat. 100%-solids has no carrier: everything in the bucket stays on the floor, so a single coat builds 10–20 mils, fills small pits, self-levels, and has the mass to resist hot-tire pickup and impact. It’s also nearly odorless, which matters in an attached garage.
The trade-offs are working time and thickness. With no solvent to slow the reaction, a mixed kit starts to set in 30–40 minutes at 70°F and faster in the bucket than on the floor, so it’s poured out immediately and spread with a notched squeegee and back-rolled. It doesn’t tolerate cold slabs (below about 55°F) or high moisture vapor, and it yellows under UV — which is why a professional floor puts a clear polyaspartic or aliphatic urethane topcoat over it.
Coverage runs 100–160 sq ft per gallon at 10–15 mils; a 3-gallon kit does 250–300 sq ft, so a 2-car garage takes two kits. Applied over a diamond-ground slab with a clear coat on top, it’s a 10–20 year floor; the same product over acid-etched concrete is not.