Building costs demystifying $/sq ft

[Alex U.]

I wanted to get some thoughts from some of the experts here in San Diego, regarding building. I have spoken to a few builders, and they casually throw around numbers like $250-$500sq /ft, without even asking the right questions about my project. This certainly tells, me they are framing the pricing. And what is interesting is that, whether you are building 400sq/ft or 4000 sq ft....$/sq ft hardly changes in the conversation. Speaking to one of the famous ADU builders here in San Diego, they said, if I were to build 10x the sq footage the price would go down about 12%. I find that hard to believe. Based on my experience doing full internal cosmetic interior rehab ( kitchens, bathrooms, flooring, paint, fixtures, lighting, baseboards...etc) runs about $25-$40/sq ft(labor and material)...managing the various trades...and not moving walls or utilities, etc or doing anything crazy.

The gap from $40/ft to $400 to build seems incomprehensible, mostly just pure profit for the contractor.  Would love to hear feedback from folks who have built 4 or more units at once ( MF or detached ADUs(single and separate roofs).