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Bill Allen,

The addition of a second floor could be included with a geotechnical
investigation that provides greater than the code value bearing capacities,
but to obtain these "higher" values a rather greater than normal
investigation could be required.  Our experience has been that goetechnical
investigations for residential work, that the owner wants to pay for, are
about $3,500.  This fee really does not allow enough investigation for the
Geotech to provide significantly higher bearing values.

Our experience has shown that this $3,500, larger than the structural fee?,
includes a couple of shallow test pits and testing of the recovered
material.  Chances are, depending upon the date of the original
construction, with the higher design bearing values the footings now are
inadequate for bending criteria.  Consider the assumed maximum span of a
typical code prescribed footing (reinforced or not) would have over a
"soft" spot for one story loads, and now consider the impact upon the
footing when the load is increased and the implied span is still required.

		Bill Warren, S.E.