i built a 40x60 insulated shop just 5 yrs ago, 13x20 slide door on south and 14x20 slide door on east, south door for smaller equip. and vehicles, put a pit straight in south door, east door the combines fit great, built a second story along the north wall that extends out 10 ft, gives alot of storage for parts and stuff you just don't want to throw away yet. the second story is the full 60 ft length. i put in a small 10x20 ft office in north east corner. concrete all around the outer edges for about 8-10 ft is 4 inches thick and has 2 inches of insulation under it, as just workbenches and shelves are there, main mach work area is 6 inches thick, has held up great so far, the pit has a small sump in it as sometimes our water table raises when it rains alot. a trench was put in the floor, runs at an angle across so it's handier for water drainage from different areas of the work center. i will be putting in a movable a-frame as soon as it's built. the building is heated by wood from an old coal furnace out of a house, the stove pipe from an old steel kendon 8 in auger tube. i wish i would have built it sooner in my life!!..oh yeah..the walk in door locks from the inside. sure does come in handy when the wife thinks up honey-do's..hahaha!! this building was designed so it could be added onto if_when ever needed with no problems. it's an astro building. very well constructed. also under the upstairs part, light was lacking, so i strung a light set that contractors use in big buildings, they are 50 ft long, with bulb type light sockets moulded into the heavy wire every 10 ft. they can be hung using wire or zip locks or mounted permanantly. i have them wired up as i may put more permanant lighting in later. hope this gives anyone some ideas. oh..just a reminder..if you live in snow country, frost will go in under any building (that doesn't have a foundation) approx 4 ft. so if you pour cement, make sure you insulate and_or use a vapor barrier.