my insurance agent and a contractor friend who builds single family homes in san francisco gave me similar answers. Somewhere between $350.00 / sq ft on low side upwards over $500.00+ / sq ft for higher end construction. It can go higher depending on permitting, type of material used etc. My contractor friend said he just built a $700.00 / sq ft new home (land cost was on top of this) in Buena Vista Terrace (above the Castro and Haight Ashbury. Used top end materials.