I would just use concrete paint and paint the floor. We just bought a house and the garage is already converted other than the door we still have to remove. I'm trying to talk my DH into adding a another small room on instead of just putting in a wall. My thought is maybe someday I will get a LA and will need the extra space. He told me when we were buying the house that could my sewing room. It's a 2 car just needs more lights and shelving so I've been picking up some cabinets at our Restore to put in there. It's already heated.