Exterior is 24 gauge metal. I finished and wired the place, buddy insulated it. 100 amp service. Wired for welder, lift, wall fans, in wall speakers in 4 zones. The building is done now but I have no pics to post. I installed the metal ceiling and all sliding walls are done. Made my own high bay lights from old ballast lights and installed LED bulbs, high bay has one ceiling fan and wall fan. One wall fan on second floor mostly to remove day time heat. Once house is built I will have a forced air nat gas furnace with 3 zones. ground floor ceiling height is 12 ft, second floor 8 ft. Peak height is 33 ft, high bay is 22ft. All walls are 1/2 inch plywood white washed.Thanks for comments.