Before pouring the foundation, we had to drill 37 holes down to bedrock* to secure the structure. At the project site, this meant going down 14 to 16 feet.
Here’s a brief video showing some highlights from the process.
Drilling from Mark Olbert on Vimeo.
A few things to notice as you watch the video:
- I don’t think the operator ever missed the hole when he was re-entering it. Which is pretty amazing considering he’s doing it all by eye from 15 feet away!
- The drill bit is on a telescoping assembly. With enough sections, it can go down 60 feet.
- The color of the material being brought up changes as the bit bores into the ground. The brown/black material is topsoil, the orange material is clay, and the gray material is what’s left when the bit grinds up big rocks underground.
* it isn’t bedrock, technically. It’s “unexpansive material”, meaning stuff that won’t expand when it gets wet. But for all intents and purposes, it’s a solid, secure target for the foundation piers.
