Here is what I built with only one regret that I am fixing right now. 40 X 60 with ½ scissor truss, half garage ceiling height is 10’4.5” then the other half is 15’3” at peak in center. Outside roof pitch is 5/12 inside is 3/12. I have two 4 posts one is next to the wall in the vaulted ceiling section, I stack my ‘65 and ‘67 Mustangs there, lift is a Bendpac HD 9, the other lift a Bendpac HD12 is in the center of the garage, and with all that ceiling height there is no problem lifting most anything.
Electrically everything is in metal conduit with recpt. every 10’ along the walls and every 5’ on the work bench. There are two 200 volt plugs along one wall for the welders (Mig & Stick), where most of the work is done, there are also a dedicated 220 for the compressor and two 220’s for the lifts mounted on the ceiling. Light everywhere
A 25’ work bench is across the back wall with top sections of kitchen cabinets for storage, the other 15’ is tool boxes, lathe, metal cutting band saw and compressor. Two pull points are in the floor about 25’ apart for frame straightening, they are each anchored in about one yard of cement. The slab is 6” in the front/ parking section and 8” in the rear section with the lifts, a bit of overkill, yes, also ½” rebar throughout. Entrance door is 9 X 16 and placed on one gabled end. Plumbed for bathroom and H & C water.
There is a 16’ X 60’ lean-to on the side of the garage, which is now enclosed with windows mounted high up on the wall (pic shows it open). Here was my error, I never factored in all the tools I had, SO a 20’ X 16’ section of the lean-to is going to be the tool/ parts room. Secure, alarmed like the garage with a 4’ wide entry from the garage. In that room will be the lathe, drill press, the 3 welders, work bench, storage shelves, Jacks, transmission jacks, engine stands, bolt collection tool boxes etc etc.
I also have an outside wood stove and heat for the garage will be a ceiling mounted heat exchanger and fan. The garage has a cable for curtains at the break where the ceiling changes, so I only have to heat ½ of the garage. With the tool room in place, there is nothing I would change. The garage can hold 11 cars using the lifts to double stack.
I thought about double doors but decided against the post between them, I have no problem with a 16' door because the garage is so big it allows plenty of room to move around, and the project cars are in the back and don't get moved often, but an 18' would only be a few dollars more