How Much Does it Cost to Build a 30x40 Garage?

When considering a metal 30x40 garage there are two styles available. The design dictates the cost, to a large degree. A typical straight-wall (gable) style garage (see pic to right) with a peaked roof is one of the two main options, a 'P-Model' (with the P standing for peaked) Quonset Hut Garage (see pic to the left) being the other.

Quonset Hut Garage Kit
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'Straight Wall' (Gable) Garage
self build garage kits & RV garages


The 'P-Model' is an aesthetic extension of the original dome shaped Quonset's, with vertical sides and a peaked roof. Typically, a Quonset garage doesn’t require a complete concrete foundation slab, as the walls can be set on narrow concrete footings instead, such is it’s stability. However, in a garage environment, this is not recommended, and a full slab should be used.

When comparing prices for either type of steel garage compared to a traditionally constructed wooden garage the real saving is in the construction labor cost. Steel garages come in ‘Kit Form’ and are designed to be built by even novice Do-It-Yourselfers with only a hand full of basic tools. A 30x40 steel prefab garage can easily be self-built resulting in a saving of as much as $20,000!

Estimate prices for the various construction methods:

Construction Method Garage Kit Windows, Doors etc. Shipping Construction Total Cost
Wood Frame Garage $14,400 $1,600 $800 $20,000 $36,800
A Frame Steel Garage $10,800 $1,600 $800 FREE (if self-build) $13,200
Quonset Garage $9,000 $1,600 $800 FREE (if self-build) $11,400


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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 straight wall metal garages starts at about $9 per square ft. Taking the roof into account, the cost of a 30'x40' straight wall garage is about $10,800. Accessories and delivery will add another $3000 to this cost for a total estimate of $13,800.

Quonset Buildings are more economical and start at about $7 per square ft. The cost of a 30 x 40 Quonset garage begins at about $9,000. Accessories and delivery are an additional $2,500, bringing the total estimated cost to roughly $11,500. If a foundation is needed for a prefabricated steel garage, its cost will add another $4 to $8 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 $20,000 (assuming you self-build)

Other popular garage sizes include: 12x14, 20x20, 22x22 & 24x24