Built my 40 X 60 11 yrs ago. Stick built on a slab 4" thick in the front 6" in the back 30'. Poured 2 pull points 30' apart in the floor to straighten frames, each one is a yard of cement with hooks for chains etc. 6" walls 10' high , the trusses are scissor trusses in the rear 30' std fink in the front that gives me 15'3" clrnc in the center. The pitch is 3/12 inside 5/12 outside. Walls and ceiling are insulated covered with painted OSB, all windows are thermopane. 16 X 9 entrance door (if I was going to do it again it would be 18 X 9) one man door. Work bench across the rear, dual 60 Gal compressors, all wiring in cndt with plenty of outlets for 120 & 220. Plumbed for bath room. Bend Pac HD 14 & HD 9. Two lean-tos on right side, one 16' X 60 with 16 X 16 machine shop in rear with lathe Drill press used as clean room to build engines, front section for parking pick-up and tractor, second lean-to 14' X 34" to park two of my Model As. No regrets except I should have built in 1978 when I built the house instead of 2008!