Here’s a scenario we run into a lot in the west–although I’ve heard some version of this from most areas in America. A single family home has two or three high volume radon fans on it. The systems are “poke and hope” but they’re designed well-enough. The radon professional and the homeowner cannot figure it out. The radon fan is operating within a normal realm on its fan curve, oftentimes lower than 1.0” of suction. The radon fan is moving a lot of air and the sub-floor/crawlspace/slab is sealed well—so we know the air is soil air. However the radon levels just won’t go down.
During a diagnostics call with me, we find out that the home is a walk-out; or it’s built into a hillside or on a hill top; or it’s in an old mining town like Breckenridge, CO. Now I see what’s happening.
Let’s use Breckenridge as an example. Breck was a mining town long before the ski industry took it over. A lot of areas were strip-mined. What was left were big boulder fields. When the town grew, homes were built on these fields quickly, and oftentimes on top of just a few feet of soil. What I’m getting at is: the soil is extremely porous—-very similar to karst geological areas. Most radon mitigators will tell you that hard clay under a home is their nightmare; however, I find that extremely porous soils can create the hardest to mitigate homes.
The technical term for most radon mitigation is “active soil depressurization”. You pull air from beneath the home and exhaust it out the roof. Well what happens when wind blows more air in through your soil than you can evacuate with a radon fan? Depending on the lot size, footprint size, wind conditions and soil conditions, some of these nightmare homes can have thousands of CFM blown in through concrete floors, basements, crawl spaces—you name it. No radon fan can overcome that type of pressure differential.
So what do you do? You need to get the best radon professional in 100 square miles to do some serious diagnostics. Oftentimes the only solution is a combination of traditional soil depressurization systems as well as thermal envelope pressurization using an HRV or ERV (read more about air exchange systems here).
Hopefully this blog post has created a light bulb moment with a stumped homeowner or radon professional. Please reach out if you have additional questions or would like to be connected with someone that can solve your “house from heck”. This is why using certified radon professionals trained in pressure field diagnostics is the smart move when it comes to radon.
Wind can effect radon levels in other ways. Wind direction is a huuuge factor in short term radon spikes or drops. If the wind is hitting the side of the home with windows open, then it can pressurize the home and “push” radon out. If it his the side of the home with windows closed, it can cause a negative pressure spike and “suck” more radon into the home. Using an EcoQube detector, you’ve got a slam dunk blue ribbon science fair project on your hands. Simply track hourly radon levels, temperature, wind speed/direction, and barometric pressure. Some really interesting findings will soon come your way.
Thanks for reading!
