I built my shop 36w x 80l x 14h due to the fact that I could use 2x4's for trusses for 36 foot span. I just built my dream home using a 60 x 100 x 20 steel building. 1735 sqft home 1200 showroom and 3000 garage. I hired a concrete contractor that did the slab for my shop and then a steel erector to put up the building. I had a good friend help with rough in plumbing. After building was up my girlfriends brother and I framed the house inside and she and I finished it. Permitted as a single family home in CA.

Having the slab built to plan is critical for these buildings but if you have a good resource from trusted friend, that is a great start. Some of the erectors also sell the buildings. I went with Heritage and worked with Scot. Building came in on one semi-truck. Good luck, Mike