Well, my shop is a 17x18 2 car garage and is just full as full can be. So we started building a 16x20 shop in the backyard to take some overflow. It started out as just being a shed and wood storage, but I have now decided to move tools out there.
It will house my air compressor with a line run to my garage. Also will house my planer and the overflow of tools that I do not use very often. As well as storing the garage things I don't want in my shop.
Was going to do a slab but this is a low area in my yard and I would have had to build the slab up 12 inches. So we poured 15 footers and set it up on 4x4's on concrete block. Built one of these at my dad's 20 years ago and it is still rock solid. Here are the starting pics and will update more.