In my shop there is a small area I share with other tenants with some food storage and a fridge and microwave, so I decided to close it off to keep the dust out and add a bunch of wall and loft storage space.
The frame is all 2x4 construction, fastened together with 3" deck screws (because I had an excess on hand). It was fastened to the walls with 3" deck screws and to the floor with concrete anchors in a powder actuated gun. The french cleat panels were used in my last apartment for storage and I moved them with me to my new place, but the fit perfectly in my shop. The door was salvaged from my grandparents house when I built them a newer, beefier door. Enjoy!