Knowing if your home has a radon mitigation system, and whether it's a passive or active system, is important. It's also important to know if the radon mitigation system in your Rochester, MN, Owatonna, MN, or Faribault, MN home is working correctly. When it comes to the health and wellbeing of your home and family, correct testing and accurate determination of radon levels is an essential process best left to licensed, experienced professionals.
Since 2009, Minnesota has required that all new homes are built to be radon-resistant. New home construction must use techniques and materials to help reduce or prevent radon from entering the home. This is known as a passive radon system which relies on the natural upward thermal flow of sub-slab air and soil gases through a pipe and exhausted to the exterior of the home.
What is a Passive Radon Mitigation System?
A passive radon system starts with a perforated tile system set in a permeable soil, such as gravel or pea rock. This layer is covered and sealed with plastic before the concrete floor is poured. The system is sealed and vented, typically through a 3- or 4-inch PVC pipe. This pipe extends from under the concrete slab your home is built upon up through the home and attic space to the exterior. A passive system relies on the thermal stack effect, which means the system will naturally draw air upwards. The home acts as a vacuum on the soil due to internal/external temperature differences. There are many factors, including weather, storms, winds, barometric pressure, and types of construction, but that’s another discussion best left for another time.
Could a passive radon system not be adequate enough?
There are several factors that may result in a passive radon system not performing well enough to effectively reduce the radon gas levels in your home. Sometimes, systems are inadvertently obstructed during the construction process. An unobstructed system is critical for adequate and consistent air flow from under the slab.
For example, my home, built in 2017, is a 1-story slab on grade with a passive radon system installed. I oversaw the installation and confirmed that it was installed correctly. After living in my home for a few months, I tested the radon gas levels, and they came in at an average reading of 3.2 pCi/l to 3.8 pCi/l, depending on the season. This is pretty close to the EPA Action Level of 4.0 pCi/l.
Does this mean my home's system wasn’t built well? No… it means that the release of radon gas from the soils below my home is greater than what the passive system can handle. I’m sure there are cold and windy winter days where the average is above 4.0 pCi/l
Is the system working good enough? The radon measurements are below 4.0 pCi/l, so some may say yes, the system is working as designed. Some may answer no, because the radon average measures pretty close to 4.0pCi/l. The honest truth? Even the best designed and installed passive system may not be adequate in all homes.
In summary, a passive radon mitigation system doesn't always guarantee that your home is safe from dangerous levels of radon gas. The only way to accurately know the radon levels in your home is to have it tested. HomePro Inspections employs the licensed and certified professionals required to ensure radon testing is performed correctly and all testing protocols are met.
Visit our website to learn more or to schedule radon testing for your home. You can contact us today at (507) 202-8942 or utilize our online “Schedule Now” feature to set up an appointment.