Insurance companies are notorious for low-balling the cost of building. My agent tried to convince me that my just-remodeled house (in 2001)could be replaced for about $95 per square foot.
Costs can vary widely, depending on the amenities and items such as number of bathrooms, etc. A bathroom is much more expensive per square foot than say a bedroom. Assuming a single custom home (as opposed to builder tract) for middle-of-the-road typical 2400 s.f. in SD I would guess about $150 per square foot these days. Assuming a general contractor. If you acted as your own GC and managed all the subs, it could be reduced by perhaps 20% if you are experienced. For the major builders the costs are significantly lower because of leverage in the size and continuity of the jobs for the subcontractors. Additionally, it is easier for the subcontractors to work on a dozen consecutive similar projects than a dozen completely different ones with differing levels of plan detail and customer quirks.
