My sister, Calley, recently bought a home in New Brighton, MN. She had a radon test done during the home inspection. The radon was 2.5 pCi/L.
After she moved in, I was looking at how we were going to install the radon mitigation system. I happened to look behind the furnace and noticed that it didn’t look like there was concrete underneath it. I ended up removing the return duct from the side of the furnace and was able to see a hole open to the soil.
This opening to the soil is an easy pathway for radon to enter the home. Radon entry can be increased when the furnace fan is operating as it could create suction on the soil that draws more radon into your home.
This opening under the furnace is fairly common in older homes that were built in the winter months. The concrete floor can’t be poured if there is frost in the soil so builders will heat the home during construction to allow for the floor to be poured.
Now To Seal the Opening
Next, we used a garden hose to rinse the dirt off the concrete and a shop vac to suck up the water. This gave us a clean surface for the new concrete to stick to.
Then we mixed up half a bag of premixed concrete and filled in the void.
The last step was to connect the return duct and turn the furnace back on.
When doing radon mitigation, we want any openings from your home to the soil sealed as much as possible. This allows for a more effective and efficient radon mitigation system to be installed in your home.