Radon mitigation in Duluth, MN

What a radon mitigation system actually does

Radon comes from uranium breaking down in the rock and soil under a house. The gas moves through the ground and enters through whatever openings a foundation has: slab cracks, the joint where the floor meets the wall, sump pits, floor drains, utility penetrations and the hollow cores of block walls.

Air pressure inside a house is usually a little lower than the pressure in the soil, especially during a Duluth winter when warm air rises and leaves through the upper floors. That difference pulls soil gas indoors. A mitigation system reverses it. The most common design is active sub-slab depressurization: the installer drills a suction point through the basement slab, removes a small pit of material below it, and runs PVC pipe to a fan. The fan runs all the time, holding the space under the floor at lower pressure than the basement. Radon is drawn into the pipe and released above the roofline, where it disperses in outdoor air.

The fan is normally mounted outside the living space, in an attic, a garage or on the exterior of the house, so the positively pressurized section of pipe does not run through rooms you live in. Sealing cracks helps the system work, but EPA does not recommend sealing alone as a way to reduce radon, because it has not been shown to lower levels reliably on its own.

How the install usually goes

Most single-family homes are finished in one visit, often within a day. MDH requires the pipe to end above the edge of the roof, at least 10 feet above the ground and away from windows and doors. A typical job has these steps:

• The contractor reviews your test result and walks the basement, looking at the slab, drain tile, sump, drains and any finished walls.
• A diagnostic check under the slab shows how freely air moves there, which decides how many suction points the house needs and where they go.
• The core is drilled, the pipe is routed to the fan location, and the fan is wired and mounted.
• Accessible cracks, joints and the sump lid are sealed so the system is not pulling basement air.
• A U-tube manometer or similar gauge is installed on the pipe, so you can see at a glance that the system has suction.
• A follow-up radon test confirms the result. EPA advises testing within 30 days of installation, but not within the first 24 hours after the system starts.

What Duluth homes tend to need

Minnesota's cold climate works against you here. The Minnesota Department of Health notes that home heating systems tend to draw radon from the soil in winter, and in Duluth the heating season is long. The hillside neighborhoods also mean a lot of variety from one foundation to the next, with older stone and block basements, walkouts built into slopes, and additions on their own foundations.

Block and stone foundations can need more work than poured walls, because air moves through them more easily. Homes with drain tile may be able to use it as the suction point. Homes with a mix of basement and crawl space usually need the crawl space treated too. A finished basement is rarely a deal breaker, but it can limit where pipe can run, so mention it when you ask for a quote.

Hiring someone in Minnesota

Under Minnesota's Radon Licensing Act, anyone who performs radon mitigation in a building they do not own or lease must be licensed by the Minnesota Department of Health. MDH says that industry certification alone is not enough. Ask for the license, or check the name against MDH's list of radon mitigation professionals. That applies to anyone you hire, including a contractor you find through this site.

Minnesota also gives you some protections that most states do not. A licensed professional has to fix an MDH-issued tag to the finished system, showing the installer, the date and the license number. If your system was installed by a professional in an existing home since June 1, 2020, you can ask MDH for a free inspection by emailing health.indoorair@state.mn.us or calling 651-201-4601.

Get the details of the guarantee in writing. Ask what reading the contractor commits to, what happens if the follow-up test comes back high, how long the fan is covered, and who handles the electrical permit, since MDH notes that most installs require electrical work to power the fan.

Living with a system afterward

There is very little to do. Glance at the gauge now and then to confirm the fan still has suction. Listen for changes in fan noise. Retest at least every two years, and again after any major renovation or change to your heating and cooling, because either can change how air moves through the house. Fans wear out eventually, and when one does it is a straightforward swap rather than a new system.

Common questions