If you are looking to add a 2nd story, and wish to know that your general contractor quotes are market priced, I suggest that you obtain at least 3 offers for the work. I can provide you a short list of contractors if you like.
One additional consideration which can affect the price of your second story, not from a build point of view, but rather from a resale point-of-view, is if that newly added 2nd story creates a nice view from a new master bedroom or new family room, etc. Unobstructed views tend to add to the value of a property, other things being equal.
All the best in your endeavor.
$507.39 is the average $ per sq ft in Monterery Hts for single family homes sold over the past 6 months. Keep in mind that quality and location varies greatly, and the number of recent sales in Monterey Hts is only 6, so use caution when using the price per sq ft analysis.
If you are not already using a Realtor and if I may help you to research this further please let me know.
Patrick Lowell, Realtor, CRS