[myself248]

No! There is no horizontal boring, at least not on any system I ever touched or heard of. I don't know where that idea came from.

There's typically enough gravel under the slab and around the foundation that there's plenty of soil-gas transport without doing anything more. So the install is just a simple vertical hole through the corner of the slab somewhere. Maybe you scoop out a few handfuls of soil before sticking the pipe in the hole, but there's no horizontal boring. Here's a very typical one:

https://www.flickr.com/photos/34878756@N04/9350845974

Here's another, including a side tap to a crawlspace:

https://science.gc.ca/site/science/en/blogs/science-health/e...

Not shown is the crawlspace portion of that system, which would use a horizontal perforated pipe _laying on the surface of the crawlspace floor_ and covered with a plastic membrane that's taped to the walls:

https://www.nachi.org/gallery/radon/crawlspace-radon-system-...

At no time is pipe tunneled horizontally under the house.