Radon Mitigation System for Bismarck–Mandan Homes

How the system works in a Bismarck basement

The most common design is sub-slab depressurization. A hole is cored through the basement floor, a pipe is set into the gravel or soil below, and a fan draws the gas up and out through a vent above the roofline.

Because the fan runs all winter, the pipe is usually routed through the house and out through the roof so the exhaust stays warm instead of freezing up with frost.

Sump pits and weeping tile

The DEQ names sump pits and weeping tile drained into an open sump among the main entry points. In many homes the installer seals the sump with an airtight lid so the pit stops pulling radon in, and the system can pull from under the lid.

Other entry points are slab cracks, floor-to-wall joints, block walls and pipe penetrations. A good installer finds and seals the large ones before turning the fan on.

Installing near the Missouri River

Soil under your house differs from one side of the river to the other. Glacial deposits from the Pierre Shale, exposed along the Missouri River valley, are described by USGS as highly susceptible to indoor radon problems. On the Mandan side, the Cannonball, Bullion Creek and Sentinel Butte bedrock formations contain above-average uranium.

The installer tests under your slab before choosing fan size, since clay soil that cracks when dry can let gas through more easily than you would expect.

No state licence, so ask about NRPP

North Dakota has no radon contractor licence. The DEQ keeps a voluntary list of firms, does not endorse any of them, and points homeowners to NRPP certification. The DEQ also notes homeowners may install their own system.

Ask any installer for a certification number and a post-install test, and do not sign a quote until you have both.

Where we offer radon mitigation systems

Bismarck · Mandan · Lincoln · Rural Burleigh & Morton

Frequently asked questions