Black Shale and Radon

Throughout our time installing radon systems we experience various types of soil. Some is nice gravel and some is hard clay. But generally, there are tricks and workarounds to whatever subsoil there is.

One type though is more troublesome than others. It is black shale. This rock overtime breaks down into a very tight sand that doesn't allow air to move through it easily. We generally see it underneath older homes and it is almost always closer to Lake Erie, for example Ashtabula, Painesville, Bay Village, Lakewood, etc.

This is due to the time period that the rock was formed and the fact that it is closer to the surface along the lake. To support this, it is the same reason that the closer north you get to Lake Erie, the shallower you have to drill to find oil (which is found in the shale).

Another aspect to black shale is that it tends to have higher levels of uranium throughout it, which is where radon comes from.

The fact that it is extremely hard to pull air through this soil and that it is often accompanied with radon levels in the mid teens or even twenties requires us to be extremely diligent in our design process. This includes almost always putting in multiple suction points and making sure to do an airflow test underneath the slab to ensure that two suction points is enough.

This took us a little bit together, but once we did it saved us so many trips back to the job site, having to redesign or add suction points to existing systems.