Building a workshop or shed costs about $3,000. Greenhouses can cost as much as $17,900. Check out the Cost Guides below for these and more detailed outbuilding project prices.Click to see full answer. Considering this, how much does it cost to build a large workshop? 40×60 Steel Building Costs: Style Material Cost Cost per SF Rigid Frame From $17,000 $7-9/SF Quonset Hut From $14,000 $6-8/SF Similarly, how much does it cost to build a 30×40 shop? The cost of a 30 x 40 Quonset garage begins at about $10,000. Accessories and delivery are an additional $2,500, bringing the total estimated cost to roughly $12,500. If a foundation is needed for a prefabricated steel garage, its cost will add another $4 to $8 per square foot. Thereof, how much does it cost to build a 30×30 shop? If you’re looking for something simpler and more economical, 30×30 carport cost estimates are typically from $3,745 to $4,345, depending on the style, including 6-foot legs and a carport roof. If an open structure is fine for your needs, this is another option to consider.How much does it cost to build a small workshop?Building a workshop or shed costs about $3,000. Greenhouses can cost as much as $17,900.