"aemeijers" wrote

That is what is in my garage with no problems. It is ground gypsum
mostly. I put a coat of primer on it but never put a finish coat.
Probably never will. Oh, I did not tape and mud it either.

Usually not recommended due to temp/humidity swings and the resulting
condensation. Even if it doesn't get wet to the touch, it can still soak
up moisture. Unless your well house/shop has stable humidity, the rock
will be prone to getting funky and soft after a year or three. The
exception would be arid climates, where nothing rots.

Perhaps, but the climate in the detached garage is the same as my house
except during heating season. YMMV