alot of sub surface investigation has been done in the county, you might try contacting them for info on a given site… sangis.org comes to mind… or if a previous developer had surveyed the site…

in fact, the county (or city) can probably tell you what you need in terms of building requirements. depending on the subsurface conditions, maybe they’ll let you get away without using an engineer. just scrape the top soil and pour a thick slab. they may want an inspection (fat ass city employee) for the concrete, verify the contractor is pouring thick enough or whatnot…

just ponderings. either way, i’m sure contacting the city engineer is the best place to start.

and your insurance co. they might have a say on the matter, if they cover settlement/foundation damage.

hmm. maybe get an engineer. what’ll it cost, a couple thou to have him dig a hole, look at it, lab the dirt and provide specs and testing? let him sign off on it…