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RE: FOUNDATIONS: "Geotechnical Report Required?"

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The United States Department of Agriculture did a large series of soil surveys and have generated maps to give the user an *IDEA* of the types of soils that *MIGHT* be present in a particular area.  The maps are actually very well put together and quite descriptive, though they do not give you design values to hang your hat on.  However, you might be able to use these maps and soil descriptions to see what type of soils are at least to be expected in the project area -- if the "shrink-swell potential" is categorized as moderate or high, then you have physical proof to present to the architect that a soils report is definitely warranted and you will be more comfortable about taking a hard stance on the issue.
Another suggestion would be to go to the building department and ask to see a soils report that might be on file for a recent project in the area:  All submittal documents are public record and you can ask to see them -- you can't take and make copies, but you would be able to see what's been used successfully on recent projects in that area -- more proof to the architect.
Dave K. Adams, S.E.
Lane Engineers, Inc.
Tulare, CA
-----Original Message-----
From: Bill Polhemus [mailto:bill(--nospam--at)]
Sent: Monday, August 16, 2004 11:30 AM
To: seaint(--nospam--at)
Subject: FOUNDATIONS: "Geotechnical Report Required?"

This may seem like an odd question, but in truth it has never come up before because it has always been understood that a geotechnical investigation is or would be required for light commercial foundation design before I would proceed to do it.


But I have a job now from an architect whose response to my query “where’s the geotechnical report” was “no report available, please proceed.” And after some digging it appear the answer to the question “does the Building Code require a geotechnical investigation” seems to be, in most cases, “no.”


I balk at this notion that I should reasonably be expected to do a foundation design without the benefit of a geotechnical report particularly in this neck of the woods, where lightly-loaded foundations get pushed around pretty good by expansive soils. Yet I cannot for the life of me find anything in the building code (SBC 1999) that REQUIRES a geotechnical investigation. In fact, the only reference to such an investigation is in Sec. 1804.2 “Soils Investigation,” which actually tells you NOTHING except that its up to the owner to pay for such an investigation if required by the Building Official.


I’m going to the particular Building Official in question for an “official” response to my question, but I’m tempted to give my regrets to the architect and tell him that I just don’t do a foundation design without a geotechnical report, period.


FWIW, the Texas Board of Professional Engineers is on record as stating that “the engineer is ultimately responsible for his design and the basis for it,” warning practicing engineers that they can’t beg off with “the owner wouldn’t pay for the geotech report.” It’s still my look-out, no matter what.


I’m not complaining about the proposed fee on the job, but it would look awfully tiny, indeed, were a foundation failure to result and I get sued. And I’ll guarantee you: If I should come up with a “super-conservative” foundation design, they won’t invite me back next time anyway, as this particular owner depends on this particular contractor for all his construction needs. If the contractor says “sorry, gotta charge you for this ‘humongous’ foundation that the engineer done drawed up,” that would be the end of our brief friendship.


Comments invited.