Does gross living area include the garage?

No. A garage is never part of gross living area under ANSI Z765, whether it is attached, heated, insulated, or finished with drywall. The appraiser measures it and reports it on its own line as garage space.

The reason is the finished-area test. Living area has to be finished for year-round living and connected to the rest of the house through finished space. A garage is built for cars and storage, so it fails no matter how nice it is inside.

The one exception is a completed conversion. If the garage has been turned into a finished room with a finished floor, ceiling, heat, and a finished doorway into the house, the appraiser treats it as a room. Listings sometimes include the garage by mistake when the number comes from tax records, which is one reason a listing can be larger than the appraisal.