After working for four small to national home builder in Colorado and building in over 60 communities along with over 10,000 homes, we varied in hard costs from $50/sf up to $200/sf, so again many of the answers below are certainly correct.ood question, but too many variables to answer without more detail. Location, size, level of finish and many other factors can cause the costs to soar. You could build a home for $150 to $200 per square foot, but certain areas and finishes could conceivably double that amount. Especially when you say 'custom' home.