Other Cost Considerations:
The cost for building a 30x40 prefabricated steel garage depends in part on the design of the building and the extras that are involved. Variations in doors, windows and insulation will affect the total price. The cost of labor may also be a factor, though in many cases you can eliminate labor costs by handing construction with a crew of friends and some basic lifting equipment.
The cost for a metal garage starts at approximately $11 per square ft. For a base building kit, the cost of a 30'x40' straight wall garage is about $13,200. Accessories and delivery will add another $3,000 to this cost for a total estimate of $16,200.
Quonset Buildings are more economical and start at about $16 per square ft. The cost of a 30 x 40 Quonset garage begins at about $10,800. Accessories and delivery are an additional $2,500, bringing the total estimated cost to roughly $13,300. If a foundation is needed for a prefabricated steel garage, its cost will add another $5 to $10 per square foot.
In contrast, hiring a contractor to build a traditional (stick built) wooden 30x40 garage can cost from $35 to $45 per square foot, for a total cost of $42,000 to $54,000. This equates to a saving of around $10,000 (assuming you self-build).
Other popular garage sizes include: 12x14, 20x20, 22x22 & 24x24, 40x30, 40x60