I am in the planning stage of a more complicated project.
I am looking for experiences (positive, but negative may be useful too!) with horizontal drilling in clay under a slab.
Core drilling through the foundation is not the issue, consider it done.
I am looking for recommendation for:
(1) which motorized mechanical drill to use (or experiences with hand coring/drilling tools) and
(2) what core/drill/auger tip to use and
(3) whether extension pieces exist to drill up to 16 feet distance
(4) Finally, I need an idea how accurate it is to bore with a recommended tool/method (depends of course on rock density).

All of this from a manhole while reaching through a cored foundation wall, or deep enough to go under a footer. I imagine any motorized tool would have to be able to be anchored against the foundation wall.

Also not unimportant: assume all pipe obstructions are exactly known under the slab.

I have found tools on line but am looking for specific experiences of people in our industry.

Leo Moorman
Radon Home Measurement and Mitigation, Inc.