Block radon from entering your home feature image
Block radon from entering your home feature image

How To Prevent Radon Gas In Your Home

By Mike Holmes

Mike’s Advice / Home Safety & Maintenance

Friday, August 17th, 2018 @ 8:07am

My son and I have been talking about the dangers of radon gas for years now. You’ll even see in our show, Holmes and Holmes, that we test all our projects for radon gas – and have taken steps to mitigate it and install radon mitigation systems.

What is Radon Mitigation? 

Radon mitigation is any process or system used to reduce radon concentrations in buildings. A radon mitigation system reduces the indoor radon level as low as reasonably achievable. 

I have partnered up with Radon Environmental, a fantastic company with radon professionals committed to removing radon from your homes. They supply testing and radon mitigation products to my projects. You can check out the radon testing options here.

Is Radon Testing Really Necessary When Buying A Home?

Homeowners should consider a radon test before making a home purchase. Budgeting for a radon mitigation system, if needed, should be a consideration when buying a home. correcting a radon problem before making final preparations to sell a home. 

My Holmes Approved Homes builders like RDC Fine HomesCharette Custom Homes, and Sonbuilt Custom Homes Ltd. have stepped up to build better homes that protect against radon because they believe in building healthier homes. 

What Are the Benefits of a Radon Mitigation System?

Radon is the #1 cause of lung cancer amongst non-smokers. Some techniques prevent radon from entering your home while others reduce radon levels after it has entered. It is generally recommended to focus on radon mitigation methods that prevent the entry of radon.

The use of sealing alone has not been shown to lower radon levels significantly or consistently. Radon can enter through the soil, windows, floor drains, and more. Check out the potential entry points for radon gas in this article.

The cost of a radon mitigation system ranges greatly. It can cost anywhere between $500 and upwards of $2,500.



Presence of Radon Gas

Radon is present in every indoor environment so everyone should build with a radon mitigation plan in mind, regardless of where they live. The geological make up of the soil and bedrock certain areas are prone to have higher levels of radon – but any home can have dangerous levels of radon, regardless of geography.

Did You Know?

In Canada Calgary, South Western Ontario, and the Interior of BC are examples of areas where high radon gas levels have been recorded but there are many more. In the USA certain states have recorded high levels, including PA, NH, NC and MN

Radon Mitigation for Your Home

All homes have some levels of radon. Only a test will identify the actual levels. Start by getting a radon test (or a test kit). You can buy a short-term test or a long term radon test. Send your radon test for results to determine your next steps.

A device called a Radostat that attaches directly to your HRV is also a good idea. It consistently monitors your home for any spikes in radon gas. It triggers an air exchange if the radon levels are peaking at dangerous levels.


Here is a detailed look at Mitigating Against Radon in 100 days or less.

Radon Mitigation for New Homes

Testing for radon is easy. You can order a radon testing kit or have an Indoor Air Quality Test performed by a home inspector.

But when it comes to new home construction, how do you prevent radon entry? I’d like to introduce two products to you; Radon Guard and Radon Block.

Both products are the only Canadian Construction Materials Centre (CCMC) approved alternative to the prescriptive gravel and vapour barrier in the code.


Radon Guard is, a structural sub slab insulation panel that creates continuous ventilation below the slab, and Radon Block is, an engineered vapour barrier that blocks Radon from diffusing into the home.

By using these products, coupled with a 4” vent pipe from below the slab that exhausts outdoors, builders are making it right and above code standard, which will go a long way towards radon proofing a home. 


Building A New Home? Have You Considered Radon Mitigation?

RDC Fine Homes & Radon Reduction Systems 

The RDC Fine Homes project is a new build, set on the mountain in Whistler, B.C. They’re all about delivering a healthier home that’s as energy efficient as possible. For this project, they’ve partnered with Radon Environmental to install the Radon Guard and Radon Block to guard the home – and its homeowners from radon gas.

In the event the home still tests high for radon gas once completed, a sealed radon fan will be added to the home, to truly mitigate the issue.

RADON MEASUREMENT: The concentration of radon in the air is measured in units of picocuries per litre (pCi/L) or becquerels per cubic meter (Bq/m3). 

Installing Radon Guard and Block

Radon Guard and Radon Block can be installed on any site by labourers or carpenters. 

Carbicrete - Mike Holmes - Construction

It takes two people roughly four hours to install the Guard and Block in a typical home.

Protecting from Radon at The Construction Stage

Important Considerations for Builders

Builders need to consider three key points when considering installing Radon Guard instead of traditional gravel: 

  1. They are getting insulation value as well as better airflow under the slab.
  2. Gravel tends to clog over time, leading to reduced airflow
  3. The gravel can itself be the source of Radon under the home.

If you are a builder looking for products that make it right, I’d recommend looking into Radon Guard and Block. If you would like more information, you can contact David Innes, Director of Sales at Radon Environmental Management Corp.:


Make It Right®