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Radon Mitigation - Hype or Necessity?

You have heard of radon. Perhaps you have tested your home or the home you intended to buy for the presence of radon gas. If so, when you received the results, did you take any action? Did you install a mitigation pump or even refuse to purchase the home?

Is radon risk real? There is a wealth of information out there. Let’s review some facts. Let’s look at what leading agencies are saying. Then let’s review our engineering perspective on radon risk and tips on what you can do before you build or after you buy.


What is Radon? Radon is a naturally occurring radioactive gas that occurs from the natural breakdown of uranium in soil, rocks and water. The gas is highly toxic, odorless, and colorless.

What increases Radon concentration? Radon levels tend to be higher in homes that are built near large rock masses or mountains. In addition, improper ventilation causes increased radon due to lack of airflow. Simply opening a window or installing fans to promote air flow in basements can lower radon levels in the home.

How does Radon gas enter the homes? Radon seeps into homes through:

  1. cracks in basement or slab floors
  2. construction joints
  3. cracks in walls
  4. gaps in suspended floors
  5. gaps around service pipes
  6. cavities inside walls
  7. water supply

Essentially all homes – old, new, slab or stone foundation – are at risk, even if your home does not have a basement.

Where in the US is Radon most prevalent?

What are the medical effects of Radon exposure? According to the Environmental Protection Agency (EPA), Radon is responsible for 21,000 lung cancer deaths every year. Nearly 2,900 of these deaths occur among people who have never smoked. The World Health Organization (WHO) states that Radon is estimated to cause between 3% and 14% of all lung cancers, more likely in people who smoke. While statistics can be debated, scientists and researchers agree that any exposure to Radon can be harmful and may cause cancer. 

How much Radon is too much? The EPA’s limit for Radon concentration in a home (set in the 1980s) is 4 picoCuries per liter of air (pCi/L). However, under 4 pCi/L does not necessarily imply a safer home. The agency states that nearly 1 out of every 15 homes in the United States is estimated to have an elevated radon level (4 pCi/L or more). 

How do I find out if my home or the one I want to purchase is at risk?
You can purchase a do-it-yourself radon test kit online or at your local home improvement store. Kits typically cost between $10 and $30. They are not very accurate as radon concentrations can fluctuate by a factor of two. This means a quick, one-time test – even if the test takes 2-3 days – may not provide an accurate radon concentration reading of the home. The most accurate tests take up to 90 days and provide a more realistic summary of day-to-day average concentration of radon in the home. The EPA also recommends that you test various areas of your home, especially during and after renovations, and test every two years. 

You can find a licensed professional in your area or state-specific radon information by visiting and selecting your state.

Engineering Perspective

Mitigating risk when building new homes or buying old ones
As the facts state and the map shows, potential exposure to radon gas in the home is indeed a real risk. Arm yourself with solutions to mitigate radon risk. When building a new home, engineers recommend installing a sub-slab ventilation system. It is a relatively simple fix to increase ventilation below the slab. Air flows through the system, thereby collecting any possible radon that is seeping up from the soil and removing it before it reaches the slab. This system can then be adapted to an active, mechanical system if levels of radon increase. Any measures you take while building to keep out radon can prevent higher mitigation costs in the future.

As a new home ages, the slab or foundation will crack, allowing radon to enter. WHO’s website has multiple suggestions for reducing the radon concentration in older homes:

  • improve the ventilation of the house
  • avoid the passage of radon from the basement into upper living spaces
  • increase under-floor ventilation
  • install a radon sump system in the basement
  • seal floors and walls

The severity of the radon levels in the home, will dictate the extensiveness of the needed mitigation.

Here is my one recommendation - before blowing money on equipment or mitigation, try some simple techniques to improve ventilation then retest radon levels before consulting a professional.