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Everything You Need To Know About Radon Mitigation

Thursday, March 21st


Have you heard that your home is testing positive for high levels of radon? Don't panic. Radon mitigation can easily reduce your home's radon levels to a safe point. As an international network of leading radon professionals, National Radon Defense can help answer all your questions about radon mitigation.

What is radon mitigation?

Radon in New Homes

If you have radon in your home then radon mitigation can easily make your home safe again.

Radon mitigation refers to the process of reducing radon levels below 4.0 picocuries per liter (pCi/L). Ideally far below. These mitigation systems either prevent radon from getting into your home in the first place or simply reduce the radon levels in the home. These systems are further divided into either active or passive systems.

  • Active radon mitigation: An active radon mitigation system uses a fan to move radon outside of the home.
  • Passive radon mitigation: A passive radon mitigation system doesn't use a fan but is instead designed to do the same thing without the fan.

Passive systems are most commonly associated with new construction and can only work well for reducing radon levels if the builder utilizes a radon professional to properly install the system. In addition, if the radon levels are extremely high (above 8 pCi/L) then passive systems generally do not move enough radon out of the home in order to make a difference. National Radon Defense recommends active systems because they work the best at keeping your radon levels very low while ensuring your family is safe from high exposure.

If you have a passive system, the good news is that a passive system can generally be upgraded to an active system even long after the initial installation.

If you are in the process of building a new home, it’s important to utilize a qualified radon professional to install the active or passive radon system to ensure your radon system is installed correctly. If you elect to try a passive system, make sure you test your radon levels after construction to ensure that it’s working.

Is a radon mitigation system worth my money?

Absolutely. The main question you have to ask is how much is my health worth? I suspect the answer is quite a bit. Luckily radon mitigation systems are quite affordable although the cost will vary based on your situation. You might even be able to use your health savings account to pay for radon mitigation. Many governments are beginning to invest in radon mitigation including Kentucky, Colorado, Minnesota, Nebraska, and the Federal Government itself. Avoiding mitigation could cost you far more in the long term.

What are the types of radon mitigation systems?

There are several different types of radon mitigation systems designed for the various different types of foundations (Basement, Slab-On-Grade, Crawl Space) and customized to your home. Many of these systems can further be subdivided into passive and active versions. In these cases, we would almost always recommend the active version.

Basement & slab-on-grade systems

  • Sub-slab suction (sub-slab depressurization): This is the most common radon reduction method for this style of foundation. Pipes are inserted into the crushed rock or soil beneath the home either through floor slab or occasionally from the outside of the home. Often only one pipe is necessary, but sometimes more may need to be installed. In the case of the active version a fan is added to the system to draw in the radon and redirect it to the outside of the home.
  • Drain-tile suction: If the home already has drain tiles or perforated pipes to direct water away from the foundation then sometimes suction is simply added to these existing pipes to let them redirect radon in addition to water.
  • Sump-basin suction: This is a variant of sub-slab suction that takes advantage of an already existing sump pump and basin. The sump basin is capped and then used as the location for the radon suction pipe.
  • Block-wall suction: This method is similar to sub-slab suction (noticing a pattern?) and takes advantage of hollow block foundation walls to both depressurize the walls and remove radon. Often this method is used in conjunction with sub-slab suction. Block wall suction is the least common approach and is typically not necessary to reduce radon levels.

Crawlspace systems

  • Sub-membrane depressurization: This is generally considered the most effective mitigation method (provided it’s installed properly by a qualified radon contractor). In this method a reinforced plastic liner is laid over the earth floor and then a vent pipe and fan combination are used to suck the radon out from under the sheet and into the outdoors.
  • Venting: Installing more vents in the crawl space can sometimes prove an effective method for removing radon. These vents can either be passive or made active by adding fans. However, this method is not recommended because it results in increased energy costs, could increase humidity levels (which may cause mold growth), and can lead to insulation problems during the winter. We highly recommend to never use venting as a mitigation strategy, unless utilizing an Energy Recovery Ventilator, or Heat Recovery Ventilator.

Other systems

  • Sealing: Sealing cracks and other openings in the foundation makes it harder for radon to enter the home and is a part of many radon reduction approaches. However, this is not very effective as a stand-alone method and is best used to complement the installation of a radon mitigation system.
  • House/Room pressurization: This method relies on a fan to blow air into the basement or living area from the outdoors or the upstairs. The idea is that this creates pressure at the lowest levels that stops radon from entering in the first place. As you might have guessed, there are many variables that can affect the effectiveness of this method and it is almost never the first choice.
  • Energy recovery ventilator (ERV): A energy recovery ventilator increases your home’s ventilation by introducing outdoor air into the home while using heated or cooled air to warm or cool this incoming air. The ERV has proven to be the most effective system to improve overall indoor air quality. Properly installed ERV’s by qualified radon professionals can reduce radon levels up to 75%.
  • Natural ventilation: Opening windows, doors, and vents near the basement can help to improve radon levels. However, this is only a temporary method since levels return to normal when the doors, windows, and vents are closed again.

Do radon mitigation systems require maintenance?

Most radon mitigation systems are fairly self-sufficient, but like furnaces and chimneys they will need occasional maintenance. Most systems use warning devices to warn you when they aren't working effectively so make sure to check on your system from time to time in order to make sure it's still working properly.

Most radon mitigation systems use fans and these fans will generally need to be repaired or replaced every five years or so. Remember, the system will not work properly without the fan. Sometimes weather can also cause problems like ice jams.

Energy recovery ventilation systems (ERV) also require some maintenance and periodic cleaning. As a general rule:

  • Have the ventilator inspected by an HVAC professional once a year
  • Periodically inspect the outside vent for debris
  • Change the interior vent twice a year

It’s recommended to perform annual maintenance on your radon system to ensure it’s working effectively.

Do new homes come with radon mitigation systems installed?

Yes, some do.  But not all. It’s important to talk to your builder and request a radon system be installed by a professional radon company during construction.

As the dangers of radon become more and more apparent an increasing number of builders are designing homes to have inbuilt radon mitigation systems. This is fantastic, but not a perfect solution.

The problem is that many of these radon mitigation systems are passive and are simply installed without measuring radon levels first. Remember what we said about passive systems earlier? Passive systems work if radon levels aren’t already too high. That means it’s still in your best interest to test for radon even if you know your home already has a passive radon mitigation system. If your home’s radon levels are still too high then you need to upgrade that passive system into an active one.

Luckily a professional radon contractor can activate a passive radon mitigation system fairly easily. They can carefully measure your existing system and install a correctly sized inline radon fan. These fans are designed to run continuously on low power and without producing much noise. That means you will likely not even notice the difference while still lowering your radon levels to a safe point.

Are condos and apartments required to get radon testing or mitigation?

Radon in Apartments

Radon testing and mitigation in apartments and condos can save many families from dangerous health risks.

Yes. The Department of Housing & Urban Development, the Dept. of Energy, the Environmental Protection Agency, and the Dept. of Health and Human Services partnered with the White House Council on Environmental Quality to launch the 2013 Advancing Healthy Housing Strategy.

The Advancing Healthy Housing Strategy effectively requires that multifamily housing gets radon testing and radon mitigation in order to receive HUD financing or re-financing. One important note is that both radon testing and (if necessary) radon mitigation must be supervised by a certified radon professional.

National Radon Defense can help if you need to have a radon mitigation system installed for your home or multifamily housing. As a leading international network of radon professionals, our membership consists of certified radon professionals around the country. Contact us today to learn more about radon mitigation and schedule your free estimate!

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