A garage-style building with high ceilings and an overhead door is hard to beat. Open it up in nice weather for fresh-air workouts, close it in winter with a mini-split running. The overhead door also makes it easy to move heavy equipment in and out.
Size depends on your setup. A 12x16 handles a squat rack, bench, and some floor space for stretching or cardio. If you're building out a full home gym with multiple stations, go 12x24 or larger. Make sure you've got electrical for lighting, a fan, and a speaker. Add rubber mats over the floor to protect it from dropped weights, and you're set.



