Can A House Fail a Radon Test After Mitigation?

The short answer is: YES. When questions come in from potential clients inquiring about radon mitigation, we often will get the questions “What if we do all of this work and the house still fails?? “Do you guarantee your work?”

Let’s breakdown some cause and effect issues regarding radon fans and installation techniques.

Simply stated ~ Any reputable, licensed radon contractor will guarantee their work as well as the materials they utilize. So how is it possible that a home can still fail a radon test after a system has been installed?

Statistically speaking, 1 in 100 homes will fail even after installing a radon system. Although that can sound alarming, there are some common reasons this can happen.

Water: It’s the easiest one to understand. A home that has a high water table, or is known to easily flood can and often will be tougher to mitigate. Not impossible, just more difficult. An active radon system works by depressurizes under your foundation and it does this through the series of pipes installed, suction point(s) and a radon fan as it moves air.

Air cannot travel through water. Period. The water issue must be corrected by the homeowner – this is not the fault of the radon system. Get the water level down and Voila! The radon system will do its job.

Inaccessible foundations: This is a big one and a common occurrence. There are times when during mitigation there is other foundations/footprints of a home that is not able to be accessed to be treated. Reasons vary but can simply be that you have a finished area blocking off the entry to said area.

Sometimes there is a footing that is separating the two foundations preventing communication under your slab. You cannot guarantee what you cannot address. There are solutions if this should happen and your contractor should be discussing these solutions with you PRIOR to your remediation.

Sump Pump Failure: This goes back to the water explanation. We’d expect to find your sump pump in good working order. If your sump pump has or is failing, it cannot keep your groundwater levels at bay. This can keep your radon system from working effectively. Resolution? Fix your sump pump!

Existing Radon Systems: This a discussion we have regularly when we are asked to activate or as we are told by homeowners, “I just need the radon fan.” New homes being built now have radon stacks already installed and are referred to as a skeletal or passive radon system. During construction of a new home 3 others trades have designed and built the passive system. They consist of the builder, the plumber and the electrician.

If a home fails a radon test after a fan is installed, and the fan has power, that is not the fault of the mitigation company – it’s a problem with the builder system that had been installed at the time of construction. Various solutions would apply if that were to happen.

Another question we get daily ~ “Do I really have to retest the house after mitigation?” Yes.Yes.Yes. The only way to validate the reduction and “passing” radon levels is to have a retest following mitigation. Illinois Radon Code says you must wait a minimum of 24 hours prior retesting to allow the system to do it’s job. We always advise: After 24 hours and before 30 days.

**If you have found this article to be helpful, consider sharing it on your social media page. Christopher Bice is the founder of Guardian Radon Mitigation & Electrical Services, LLC. Christopher is an Illinois licensed Radon Mitigation Professional through IEMA.

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Guardian Radon Mitigation & Electrical Services®
451 Burr Oak Drive
Oswego, IL 60543