Houston and Expansive soil

[Captn]

I've been told that Houston has problems with it's Gumbo Clay, or expansive soil. Three types of foundations are common here, pier and beam, where the hole is drilled up to 18 feet deep with a 36 inch diameter base, a slab on grade, and a torsion beam slab.

I have three questions ...

1.) Has anyone built a LHBA style log home in the greater Houston area and if so, what style foundation did you use?
2.) Is the LHBA standard pier and beam that goes just down below frost line acceptable for use in expansive soils?
3.) Is a Slab on grade or a Torsion beam slab acceptable for use with a LHBA style BAP log home?

[edkemper]

1.) Look over the member built homes. There are a number of members from TX.
2.) Yes. Remember, most of our plans are drawn by architects or engineers. They are who tell us how what to do, for our particular needs.
3.) These are questions the class will cover 100% and in great, sufficient detail.

[StressMan79]

expansive soils, eh?
I had never heard of them... basically they heave whenever they get wet, not just when they freeze/thaw... you can of course build anywhere, so long as you do the right thing to prevent issues. When worrying about frost heaving, we dig to a depth where there is no freeze/thaw. a similar attack may be taken in this sort of soil--dig to a point where the soil is of a more or less constant water saturation. I am not a licensed PE, and I have no experience with these, but the Pier method that is suggested in the class is very resilient to lots of soil conditions.
http://geology.com/articles/soil/expansive-soils-map-560.gif
the original pic and the corresponding legend is here: http://geology.com/articles/expansive-soil.shtml
you will have to speak to a geotechnical engineer about the specific plot you are looking at. You may have to dig 8 ft to minimize these effects. In which case, I'd suggest a full basement, lots of drainage rock, and 10" walls and lots of rebar in the footing.
-Peter

[ragdump]

Ragdump
Cool my place is in the middle of the brown zone ,the dirt around me is mostly decomposed granite when it gets wet it just gets harder

[StressMan79]

the website changed the location of the map, so the link quit working.
http://geology.com/articles/soil/expansive-soils-map-900.gif

[Captn]

Thanks Stressman ....The problem here is the water table ...A full basement in Houston is called a Swimming Pool!

[ragdump]

Ragdump
the water table so hi this time of year around my place I hit water digging fence post