They’re building a couple of new houses in our neighborhood and the last few days they’ve been digging the basements. When I was growing up in Oklahoma, I think the only house that I knew of that had a basement was our house — and that wasn’t really a basement, more of a very small cellar under one corner of the house.
When I came to the Washington D.C. area, a house without a basement was a rarity.
I got to thinking about this and at first, it really didn’t make much sense. During a tornado, the safest place is usually underground. We had lots and lots of tornadoes in Oklahoma and none of the houses had basements.
As you may have guessed, my extensive research mode kicked in on this one. The soil in Oklahoma is mostly red clay and that absorbs a lot of moisture. It turns our that the water table in the state is very high. The red clay soil also has a tendency to dry out in heat and that causes contraction and expansion that puts a lot of pressure on concrete-reinforced walls in basements and they tend to crack.
And then there’s the frost line — the level that it freezes down to in the winter. That line is fairly high in Oklahoma because it’s warm. Building codes require sinking the foundation down below the frost line. In a place like Cleveland, when you excavate to go down below the frost line to put a slab in, you’re already halfway there to be deep enough for a basement. In Oklahoma, you don’t have to dig down that far, so the upfront cost to put in a basement is higher.
I’m pretty sure that with today’s technology, it would be relatively easy (maybe not inexpensive) to build a good, solid, dry basement. But people that live in Oklahoma have the perception that they always leak. That, along with the added expense probably means that Okies will continue to build “safe rooms” as their preferred protection from tornadoes….
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