I built a 40x60 Nucor I-beam type commercial steel building in 2004 with the following specs;
-14' side walls
-2:12 pitch, stitch down i.e. screwed roof (not standing seam which is nicer, but VERY expensive)
-12" overhangs on all sides
-Commercial style gutters that match the eve trim
-Two 12x12 insulated overhead steel doors with openers and 3 insulated windows each
-One 8x8 insulated overhead steel door with 2 insulated windows
-Two insulated comercial steel man doors and 3 insulated windows
-Fully insulated with 4" fiberglass insulation.
-6" thick concrete floors with radiant heat and fully insulated under the slab
-65'x20' concrete apron on one side of building and 8'x10' apron in front of smaller overhead door
-Plumbed for future restroom
-Floor drains in front of each of the 3 overhead doors
-A 20x20 enclosed area in one corner for a future office, with mezzanine storage above it rated at about 45 PSF per foot. If this starts to sag I will build a wall in the middle (which will be there anyway for the future office) and then weight capacity is virtually unlimited
-Fully wired with EMT conduit, a ton of recepts, and lights are nine 175 watt commercial metal halide lights, as well as 15 2'x4' four bulb flourescent ceiling lights hung from 3/16" steel cables. I also have four 2 bulb x 8' flourescent ceiling lights as well as a 400 watt metal halide floodlight outside between the two large doors which really produces a LOT of light when needed on the apron and driveway. The flourescent lights are used for instant light, and the metal halides are used when I will be working in the shop for a while as they take about 5 minutes to fully power up.
I really like the I-beam construction as the building is very open inside, which is especially important in the mezzanine storage area. And I could hang an overhead lift from the beams in the future if I wanted to.
I did the outside concrete work, all electrical, plumbing and radiant tubing installation and the mezzanine storage area work myself. At this time I have about $52k in it, which is more then I wanted, but in construction it seems that things always cost more then expected. For one thing, the site sloped enough that in 60' I needed 3' of fill on the low end which amounted to 23 tri-axle loads of fill dirt. I have less then $500 in all the lights, as all were used except the floodlight which I bought on ebay for $70, but the conduit, wire, switches, etc were over a grand, as I have almost a mile of THHN wire in the building. Radiant heating added another $2,500 just for the tubing and underslab insulation, but it sure is nice. I got a great deal on 24 like new TGI floor joists for $100 for the mezzanine floor supports. Normally these sell for $1.69 per linear foot, while I paid about $0.21 a linear foot.
The building, insulation, man doors and all fasteners were a little less then $14,000 from
www.steelbuildingsupplier.com in 2003, but erection was about $13k and footers, foundations and interior concrete and sitework was around $14k. I think steel buildings are higher now, as I bought it just before steel prices increased. But one thing with buying over the Internet and from out of state, there was no sales tax on the building, even though it was mfg only 45 miles from my house and in my state.
I really like my building, but would I do it again? Probably, as the quality is a lot better then a pole building and I don't have to ever worry about the posts rotting off. The steel is also heavier, as all metal is 24 gauge as compared to 27 or 29 gauge normally used on pole barns. I had a quote of $32k for the same 40x60 building in a pole barn including concrete, but no site work beyond drilling holes for the posts, so the fill would have added another $3k to the job. One advantage of a pole barn and wood trusses is that it would have been much easier to install the electric as I could just have run Romex everywhere.
The key in this type of project is the contractor, as I had to fire the first guy because he wasn't getting the job done or doing it the way I wanted. This cost me an extra $3k, so it was a learning experience. I took him to small claim court, and won a judgement against him and his wife. I garnished her wages and got some of my money back until they filed bankruptcy and I was out of the balance they still owed me. Oh well, live and learn.
I am thinking about building another building just strictly for storage purposes without even pouring a concrete floor. Kinda of like most farm machine sheds. For this, I would probably build a pole barn, as it would be by far the cheapest option.