About 25 years ago when I had my house built, the contractor asked me if I wanted to have a room under the main garage. My house is on a hill with a walkout basement. At the time I thought it would make a great storage or exercise room so I said yes. I have a home with a wood foundation, so he used trusses to support the concrete garage floor above and 2X12s for the wall studs supporting the trusses. They also poured a concrete floor and installed a garage door opening to my backyard. I have access to the shop through a door from my utility room in the lower level of the house. I originally used it for storage. I finally got smart and put in lots of overhead lighting, insulation, heat, and I installed 3/4 inch plywood on the walls, covered by 1/2 paneling. This allows me to screw cabinets etc anywhere without looking for studs. I ran in a separate power panel and many 120 and 220 outlets. Although not a huge shop, it's 400 sq ft, I have fun working in it. I have put most machines on mobile bases. I have space on the walls in the home utility room for pegboard and thats where I keep a lot of my hand tools since its just outside the door of my shop. I had a garage door company cut windows into the garage door so I can look out over my wooded lot and creek, see it raining and snowing, all the time nice and cozy while building another masterpiece…masterpiece?...well maybe not…you know what I mean.