I'm getting ready to install COREtec Pro Plus LVP over a wooden subfloor in my 1985 second floor condo. The installation instructions state that "Resilient flooring is not recommended directly over fire-retardant treated plywood or preservative treated plywood." How do I know whether my floor falls into one of those categories? It appears to be 3/4 tongue-and-groove plywood, and there are spots where it just looks like bare plywood, but there's a misty light beige over most of it, which is generally heavier closer to the walls, so I suspect it may simply be primer or something that was sprayed on the walls? Any insights are appreciated, thanks!!
The concern is probably that adhesives won't bond to treated plywood, or maybe that color will leach out and stain the new flooring. You're right that you're seeing paint overspray on your subfloor. It looks like standard raw BC plywood.
Single-family residential subfloors are rarely treated, in my experience. This may not be true in some high population density communities with more rigid fire codes.
Fire-rated plywood is going to have that mentioned in a stamp on the bottom. There may not be a good way to determine whether it is from above. If you can find access to the underside from a basement ceiling you can probably see it.
Plywood treated for rot resistance is almost always green, and it's not readily available in tongue-and-groove configuration.