Lutt Looks like you've "expanded" your goals. A 24x30 will be plenty. We built a new home almost 4 years ago now, and I added a 24x30 workshop. For a cost comparison I will try to give you as complete a breakdown as I can remember. I had the slab done by pro's, and it included a 12" slab on grade reinforced footing, and 4" reinforced slab. My cost was a flat $5 per sq ft, concrete included. I helped some by tractoring in the fill dirt and compacting the fill under the slab. My lot there has a slight slope to it, so that one footing was was closer to 28" high and 12" above grade, while the other sits only about 6" above grade. The unit is stick built on site, 2x6 walls, with 10ft ceiling. No drywall or insulation inside. I wrapped the vapor barrier myself, and hung my walk out door, and both single hung windows. The roof is 4-12 pitch truss with attic trusses, stressed for storage. That leaves my a 4ft x 7ft x 30 ft storage area in my rafters, un impeded by bracing. I floored that area with 3/8" OSB. I also ran all my own electrical, and had my 8ft H x 12ft W sectional garage door professionally hung, as well as the Hardy board lap siding. I bought all my materials from the blueprint list and had them delivered onsite, as well as the trusses. The same contractor that did my concrete also did my framing. He also did the same jobs on my house. I hired some workers, that I knew had the skills and experience to hang my siding, and they worked hourly for me. I also bought the roofing materials and had them delivered on the roof and hired a roofing contractor to lay them. I would have done that myself but had just recently injured my back and couldn't lean that much. Cost there was $65 per sq. (10ft x 10ft) All told I have about $15,000 in the shop. That includes the aluminum sectional garage door, with top row of windows (lites) in it, and steel exterior walk out door and 2 single hung double pane windows. I used those cause someday it might get insulated. That also included all my California permits (about $1500 total IIRC). CA codes are strict and I avoided engineering fees by going by standard construction methods, like min of 5ft from any corner to any opening, or at least 5ft from any opening to any other opening. Also 2x6 studs and max of 10ft walls. A couple things to consider, that I would do if I were to ever repeat this job. I would have gotten trusses with a "knee wall" and the attic truss. THe knee wall would have added to the overall height of the roof, but still kept my walls to 10ft. My "attic" would then have been 6ft high (instead of 4ft) and 7ft wide, much better to walk in. You could easily sleep there. If funds and codes permit, make it stressed for 2 story. You do not have to build it as 2 story to start, but the extra room WILL be appreciated later on. That was what I really wanted but after the home build I was running low on funds, and to go a 2 story route would require engineering and a much heavier slab, would have cost my about 10K more after all was done. Plus CA had just implemented a new code requiring fire sprinklers in any building over 1000 sq ft. I only have 3 acres and couldn't get it in as an AG building. They require 20 acres min to qualify for that here. That would have made it much cheaper. But such is life. Sorry for the long post and hope it helps some.
