Somewhat like reverse engineering.

Not the engineered that's on a slab.

Get an engineer/foundation report - it will cost you $ to save $$$$$. 

That in turn needed "flow volume" plans from an engineer. 

Once you know the process what all is required in the cost associated with permitting etc. then you can reach out to engineering firm to get a proposal and general contractors to get construction cost for the houses.

I just accepted a job in Bozeman, Montana as a project engineer.

In my area, foundation companies will come out for free and structural engineers will come out for a few hundred dollars.

You can tell on older homes if this has been repaired - in a cement underpinning, for example, you would see an old crack which has been filled in with mortar of some kind - it looks like a smear.I'm not a structural engineer but have done this a long time. 

@Riley SchaeferThis question has been frequently discussed on this forum if you search it.Short story: real cost seg studies (with a site visit and an engineer's report) on SFRs are usually not cost-effective, unless you have a large portfolio concentrated in one area, and the cost seg company will give you a package deal. 

Our listing got thousands of more views than houses in the area because we nailed Zillow ranking algorithm.