National Radon Proficiency Program
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Association of Radon Scientists and Technologists

What is Radon?


Radon Gas forms naturally and continuously in the earth as a decay product of Uranium and Radium. It is pervasive because of Uranium’s global abundance and extremely long half life. The Uranium decay chain eventually produces Radon Gas. Radon Gas percolates efficiently through loose, porous soil and enters buildings through foundation gaps and cracks, utility service points, sump pump openings, floor/wall joints, and exposed soil in crawlspaces primarily. The natural pressure differential between the building and the soil creates suction that pulls Radon Gas into the building. Additionally, well water can contain significant amounts of dissolved Radon Gas which can be transported into a building increasing the building’s internal radon concentration.  Radon Gas undergoes radioactive decay with a 3.8 day half life and emits ionizing radiation through normal radioactive processes.  Decaying Radon Gas emits an alpha particle resulting in an atom of Polonium 218 which in turn also undergoes alpha particle emission to produce other alpha emitting radon progeny Polonium 214 and 210. The alpha emitting Radon Decay Products, Polonium 218, 214 and 210, are inhaled by respiring humans and pets as minute, odourless, tasteless particles that cause physical or cellular damage in the lungs.

Courtesy of Health Canada
Courtesy of Health Canada


The World Health Organization’s International Agency for Research on Cancer has classified Radon Gas as a Group 1 carcinogen along with tobacco smoke and asbestos. Health Canada recommends testing for Radon Gas concentrations in all buildings and reducing Radon Gas concentrations below 200 Bequerels/m3 in the lowest occupied level of the building. Canadians’ principal radiation source exposure is from Radon Gas which accounts for 56% of the total radiation dose received. Radon gas is the second leading cause of lung cancer, typically Brochogenic  (small cell carcinoma, large cell carcinoma, squamous cell carcinoma and adencarcinoma).  Development of lung cancer from Radon Gas depends on the radon concentration level, exposure length of time and cigarette smoking history, as Radon Gas inhalation and cigarette smoking has a submultiplicative effect. The electrically charged Radon Decay Progeny attach to microscopic dust particles inside a building and are easily inhaled where they irradiate sensitive lung tissue and slowly penetrate the inner lung surface disrupting DNA structure within lung cells causing uncontrolled replication of the damaged cells. 


Radon Gas levels can be effectively controlled in all structures with our guaranteed results and fully transferable warranty. Radon Gas Experts accurately assesses Radon Gas concentrations in homes, schools and business. We conduct specialized, controlled tests in accordance with the best quality assurance practices established by Health Canada and the Canadian National Radon Proficiency Program (C-NRPP). Short term tests for real estate purchases/ sales, ground water testing and indoor atmospheric tests are all conducted with C-NRPP compliant measurement devices. Guaranteed reduction of Radon Gas levels below Health Canada’s indoor Radon Gas concentration level action guidelines are completed effectively and efficiently with our targeted and fully Health Canada compliant soil gas mitigation services.

Who We Are

Radon Gas Experts provides fully compliant (C-NRPP # CRT 201342 measurement/ C-NRPP # CRMT 201343 mitigation) Radon Gas Measurement and Mitigation Services for new and existing residential and commercial buildings throughout Southern Ontario.


Radon Measurement

Radon Gas Experts completes C-NRPP certified Radon Measurements in homes, daycare facilities, schools, workplaces, and multiple unit residential buildings consistent with the specific testing protocols and quality assurance guidelines developed by C-NRPP in conjunction with Health Canada. Our testing devices are not radioactive and do not pose any hazards to users or occupants. We complete short term tests for real estate transactions and certified long term tests for accuracy and Tarion Warranty purposes as recommended by Health Canada. Elevated Radon Gas concentrations can occur in any building regardless of age, heating system, foundation type, geographic location, air tightness, or building materials used. Certified long term testing is the only way to definitively determine Radon Gas levels.


Long term (91+ days) Radon Gas testing provides the most accurate representation of the annual average indoor Radon Gas concentration within a building. Radon Gas levels can fluctuate significantly over the short term due to environmental factors such as wind and precipitation.  Ideally the Radon Gas testing period will include winter months as Radon Gas levels can be significantly increased during the heating season due to the stack effect. 

  1. In heating season warm air within the structure rises and escapes through the attic to the outside of the structure. Replacement of the escaped air occurs naturally to equalize the internal air pressure. The replacement air is drawn in through drafty windows and doors or through soil gases in foundation gaps throughout the structure.
  2. More radon gas enters structures during winter months as frozen ground and ground snow cover creates a barrier for soil gas which is percolating through the path of least resistance. The vacuum created by the stack effect effectively suctions Radon Gas inside the structure. 
  3. Additionally, closed, airtight houses increase the stack effect as window and door openings for fresh air are typically kept closed throughout the heating season.
Courtesy of Health Canada
Courtesy of Health Canada


Radon Gas concentration measurement is extremely important in structures with young children present. Studies indicate that children are more susceptible to Radon Gas exposure than adults are because their lung architecture and breathing patterns result in a larger radioactive dose to the respiratory tract. Research indicates that by ten years of age a child receives twice the lung dose compared to an adult who has been exposed to Radon Gas for the same time period. Additionally, children have longer latency periods in which to develop lung cancer associated with Radon Gas inhalation. Children also spend up to 70% more time in the home than adults do and are typically closer to the floor, primarily in lower levels of the home where heavier than air Radon Gas is most concentrated.  Radon Gas accounts for approximately 56% of our annual radiation exposure (200-360 millirem per year) and is the second leading cause of lung cancer. Lung cancer typically reduces life expectancy by 15 years so effective, proactive, low cost management to protect your family is critical. 

Tarion Warranty

Ontario’s New Home Warranty program administered by Tarion covers all new homes and existing warranted homes from high levels of Radon Gas effective March 25, 2013. Tarion Warranty covered homeowners can make a claim for mitigation of Radon Gas if within the seven year warranty term a new home tests at 200 Bq/m3 or above. C-NRPP Certified Radon Gas measurement tests and C-NRPP Certified Radon Mitigation systems can ensure that your home qualifies for the Tarion Warranty protections.

Radon Gas Experts as a fully certified C-NRPP measurement and mitigation Radon Gas contractor would be pleased to provide our assistance in ensuring that your only cost as a new home buyer is for the initial Radon Gas measurement test.

Courtesy of Tarion
Courtesy of Tarion
For more information about your Tarion Warranty’s Radon Coverage:
Radon gas and Tarion’s Warranty Coverage PDF

Radon Gas Mitigation

Mitigation reduces Radon Gas concentrations below Health Canada guidelines

Radon Gas Experts custom designs effective Radon Gas mitigation systems for all buildings regardless of the complexity of the structure or current Radon Gas concentration levels. We guarantee in writing Radon Gas concentration level reductions lower than Health Canada’s action guidelines for homes, schools and workplaces.  Our mitigation systems are designed and installed by C-NRPP certified mitigation professionals with superior knowledge of construction features and building code requirements. We provide every mitigation customer with a guaranteed Price and Proposal Scope of Work and a fully transferable 5 year system warranty. Post mitigation testing to ensure system effectiveness is combined with customer training to ensure monitoring tools such as manometers are read properly. Additionally, our trained and certified technicians conduct comprehensive back draft testing on the day the mitigation system is installed to eliminate any possibility of carbon monoxide gas collecting within the structure from combustion appliances. Radon Gas mitigation is a critical service that requires an accurate building assessment and strategic review by committed certified mitigation contractors to ensure an efficient and optimized durable system for all structure types. 

Soil Depressurization systems that create negative pressure in specific areas effectively gather Radon and other soil gases before they enter the building envelope.  An auxiliary benefit of a well designed Active Soil Depressurization system will be a reduction of moisture vapour entering the structure as well as potential diversion of Volatile Organic Compounds and Vapours from entering the structure. 

Courtesy of Certi
Courtesy of Certi

Unique building configurations require different depressurization techniques to achieve maximum Radon Gas concentration reductions. Radon Gas Experts’ mitigation solutions can include: Block Wall Depressurization, Sub-Membrane Depressurization, Draintile Depressurization,Sub-Slab Depressurization,Sump Pump Depressurization,  Active Soil Depressurization and Baseboard Depressurization systems; either alone or combined to achieve Radon Gas concentration reduction guarantees. Depressurization systems can also be augmented with a Heat Recovery Ventilator (HRV or air to air heat exchangers),  natural ventilation, sealing of foundation cracks and gaps, and  HEPA air filtration however these are supplemental strategies and not adequate stand alone Radon Gas mitigation techniques.

The techniques are straight forward and long term follow up studies have demonstrated that well designed depressurization systems provide long term Radon Gas reductions in homes, schools and workplaces with reasonable installation costs and very modest operating costs.

We are pleased to inspect and we can certify existing systems that meet or exceed C-NRPP and Health Canada standards. We also convert existing passive systems to active systems and can assess air flow, sub slab communication and pressure differentials to ensure the existing system design is adequate for Radon Gas concentration reduction goals. Our immediate post installation short term testing is complemented with an additional long term test to confirm concentration reduction goals have been achieved.

Our systems in addition to guaranteeing results are also designed to be aesthetically pleasing and unobtrusive.  Do not hesitate to contact us with any questions regarding Radon Gas Mitigation even if it is a system we did not install, we at Radon Gas Experts, are happy to help.

Radon Resistant New Construction

All new residential and commercial buildings constructed should include Radon Gas resistant techniques to prevent and control Radon and other soil gas entry. Radon Gas Experts sub-contracts from builders to design and install the components of a passive depressurization system or we inspect and certify systems installed by builders that meet Health Canada, C-NRPP and Radon Gas Experts’ standards.

UAF Cooperative Extension Service/Cold Climate Housing Research Center
Radon Resistant New Construction Techniques include:
  1. Installation of a gas permeable layer prior to pouring the concrete slab. This minimum 102mm, porous clean gravel layer, allows the unrestricted movement of Radon and other soil gases beneath the structure’s concrete slab. Often grade beams or intermediate footings require installation of pipe stub penetrations to support unrestricted air flow underneath the concrete pad completely. Radon Gas Experts additionally embeds approximately 25mm below the gravel surface a minimum 3 metre long, filter fabric wrapped, perforated pipe to enhance soil gas collection. As an alternative to perforated piping a drain mat system can be installed to support soil gas collection beneath the concrete pad. 
  2. Above the clean gravel layer Radon Gas Experts installs a 10mil true vapour barrier with overlapped and taped seams before the concrete slab is poured and/or above the crawlspace floor as appropriate.
  3. A Schedule #40 PVC riser pipe is secured in place and connected to a PVC Tee that is also in the gravel and connected to the perforated pipe or drain mat system. The riser pipe is kept clean and temporarily capped to ensure that the soil gas collection system is unobstructed after the concrete pour. The riser pipe is immediately labeled as a component of the radon mitigation system.
  4. Critical to system effectiveness is comprehensive sealing and caulking after the concrete pad has been poured. All visible cracks in the concrete floor, control joints, cold joints, around the sump pump, utility openings, plumbing penetrations, joints around concrete cures and expansion joints are sealed appropriately to enhance the effectiveness of the mitigation system.
  5. The temporarily capped riser pipe is subsequently uncapped and connected to Schedule #40 vent pipe to the pre-determined exhaust point. The vent pipe is installed through a warm space within interior walls ideally alongside a flue chase to maximize natural stack effect impact.
  6. An electrical junction box is pre-installed near the vent pipe in the event a conversion to an Active System with a Radon fan is required in the future. 
UAF Cooperative Extension Service/Cold Climate Housing Research Center

The International Code Council’s International Residential Code Appendix “F” ( details best practices which Radon Gas Experts follows for Radon Resistant New Home Construction with appropriate modifications in respect of domestic Canadian regulations.

Radon Gas Experts supports builders and new home consumers in ensuring these inexpensive, aesthetically pleasing systems are appropriately deployed during home construction. Health Canada recommends that Radon Gas measurement testing occurs within the first year of occupancy to ensure passive mitigation system effectiveness for new home purchasers. 

Radon in Groundwater

Rural buildings serviced by private or community wells may have elevated indoor Radon Gas concentrations from groundwater that could have potentially high levels of Radon Gas concentrations.  Groundwater contamination occurs due to groundwater flow patterns, diffusion patterns and the Uranium content of the rock the groundwater contacts. When groundwater is used in a building approximately 70% of the radon contained in the groundwater is released into the atmosphere during turbulent household water uses such as showering, clothes washing and toilet flushing, especially when the water is heated. Once the Radon Gas is liberated from the groundwater and becomes airborne human exposure occurs through inhalation.

Measuring Radon Gas in water is relatively simple and should be completed in conjunction with indoor atmospheric radon testing if your building is serviced from a private or community well. Radon Gas Experts provides groundwater Radon Gas testing services directly or easy to use do-it-yourself kits with comprehensive instructions provided. 

Remediation for groundwater Radon Gas contamination is completed at the point of entry either through Aeration systems or filtered through Granular Activated Charcoal systems. Point of use treatment methods attached to individual household taps are seldom recommended due to the limited impact they have on total household water used per day (typically 70-250 gallons per household). Specific system maintenance and disposal considerations are appropriate when groundwater systems are designed to avoid bacterial water contamination or improper disposal of radioactive waste. Radon Gas Experts is happy to design and provide on-going service support to avoid these potential issues. 

Courtesy of RIch Kuban
Courtesy of Rich Kuban
Radon Gas Experts, 2013.