So nobody had a foundation under their house?

Not now, then.

Can't stop the signal.

I thought Burt was in his basement during the guns-a-blazing scene. Plus the Graboid came through the wall (implying it had been boring underground).

Looks like they mostly lived in trailers. The store was only on wood, but maybe he just had a large backroom for storage.

Some of them would have been built on concrete slabs, but the graboids were clearly strong enough to get into the Gummers' presumably-reinforced basement, so the slab foundations wouldn't have presented them much of a problem.

Interesting, though; I hadn't considered, until now, that a graboid punched right through the Gummers' basement wall, but the one that was chasing Val and Earl after knocking them off their horses was killed when it rammed into the concrete drainage culvert.

- You may have come on no bicycle, but that does not say that you know everything.

If you want a really cheap house, yes.

Not really surprising considering the income of the people and that mostly everyone was living in trailers.

It's the middle of Nevada. There's no snow or crazy weather, so they probably didn't pour a concrete foundation. The buildings were probably erected very cheaply to save a ton of cost considering the people are fairly poor to begin with.

Warm weather allows for wood floors. Many houses in Florida have wood floors hecause they don't worry about freezing. Probably the same in the desert.

Except for the Gummers, I think most of the houses were built on pillow block foundations.