What the extra cross-linking does
A standard epoxy cures into a network with a certain density of chemical bonds. A novolac resin has more reactive sites per molecule, so it cures into a tighter network with fewer paths for a chemical to work its way in. That density is what buys the acid resistance, and it is also why novolac films are harder, more brittle and less tolerant of movement in the substrate beneath them.
Where it earns its cost
Anywhere the floor takes organic or mineral acid regularly. Winery crush pads and cellars see grape must near pH 3.4. Breweries take wort, then caustic clean-in-place chemistry within the hour. Dairies see lactic acid daily. Labs and battery charging rooms see acids at concentrations that would strip a standard clear in weeks. In those rooms a novolac topcoat is not an upgrade, it is the specification, and a general-purpose product will fail on a predictable schedule.
Where it is money wasted
A residential garage sees road salt, oil and the occasional dropped solvent, none of which trouble a standard polyaspartic topcoat in the slightest. Specifying novolac in a garage buys chemical resistance the room will never call on, at a real price premium, in a resin that is more brittle than the one you actually want there. If a quote for a home garage leads with novolac, ask what exposure it is for.
It is a topcoat decision, not a whole-floor one
The chemical exposure is at the surface, so the resistance needs to be at the surface. A typical production floor is a quartz broadcast body built for thickness and abrasion, with a novolac topcoat over it doing the chemical work. Building the entire system in novolac would cost far more and gain nothing, and would make the floor more brittle than it needs to be over a slab that moves seasonally.
Want this answered for your slab?
Free site visit with a moisture reading, then a written fixed price. Across the BC Interior.