I Just started building a Spec I will live in for a couple years and as soon as i prove concept and have my numbers verified (when complete) I plan to build another on the lot I own next door, My calculated build cost will be $125/sq ft (for just main floor finished, that will drop to $85/sq ft with my lower level finished, thats with me doing a ton of work myself, for example, I am the GC (Licensed) , I am the HVAC Contractor (licensed) and I will be doing all the tile, finish work, cabinets, flooring, ect. and for my house I will do the lower level framing, electrical, plumbing, and finish work after occupancy. If I hired that all I would be in the $150-175/sq ft. I got my lots at tax sale, and sold 1 of the 3 in a row, I have also run into snags. like my sewer connection was 17 feet down, so I had to get a big contractor in to dig deep with steel plates to prevent soil from falling in, cost an additional $9K I did not plan for. Weather has been difficult as well, because Im not a production builder subs push me back to accommodate their regular clients. my foundation walls are up, and should be back filled this week with framing starting soon. fortunately in my location the value of the completed project is worth quite a bit more than cost, so I should be ok, but that would not happen in a C area. I would doubt the finished value would be even equal to the cost to build. much less have built in equity.