Picture the foot-or-larger earth auger used to excavate a big post hole. Now imagine screwing it into the ground, not with the purpose of removing material from the hole, but of burying the auger. Run it down until the hydraulic motor stalls, adding extra sections of drive shaft to run it deeper if necessary. When you’re done, that thing is wedged pretty firmly into the ground. That’s a helical pier.

Do that a dozen times in a rectangle, cut off all the shanks level with each other, and bolt beams to them. Build a structure atop the beams. Ta-daa! Helical pier foundation. No digging, no concrete pouring, and it works in sandy and muddy places where other techniques fail. Neat stuff.

I’m sure there are downsides too, like “where do you go for a tornado?”, but I was fascinated by the technique when I read about it in the Journal of Light Construction a few years back. Looking at the HEM stuck on the machine up there reminded me of the drive technique used for HPFs, so I figured I’d post. (But then, the sky could be blue and I’d post about it.)