What is Radon?
Radon is a radioactive gas that is found naturally in the environment. Radon is formed from the breakdown of uranium, found in soil, rock and groundwater. Radon gas is inert, colorless and odorless, and is found in the atmosphere in trace amounts. Outdoors, radon disperses rapidly and, generally, is not a health issue. Most radon exposure occurs inside homes, schools and workplaces. Radon gas becomes trapped indoors after it enters buildings through cracks and other holes in the foundation. Indoor radon can be controlled and managed with proven, cost-effective techniques.
Breathing radon over time increases your risk of lung cancer. Radon is the second leading cause of lung cancer. Nationally about 21,000 people die each year from radon-related lung cancer. Only smoking causes more lung cancer deaths.
What can be done to reduce Radon in your home
You can take steps to reduce and control the amount of radon in your home. Testing is the only way to determine radon levels. Have your home tested by a professional. EPA guidance suggests mitigating if levels are at or above 148 Becquerels/meter3 (4 picocuries/liter).
The effectiveness of any one radon-reduction method will depend upon the unique characteristics of your home, the level of radon, how it is getting into your house, and how thoroughly the job is done. A single method may do the job, but sometimes a combination of several methods must be used.
Homes are generally categorized according to their foundation design: basement, slab-on-grade, or crawlspace. Some homes have more than one foundation design feature: a basement under one part of the home and a slab-on-grade or crawlspace in another area. In these situations a combination of radon-reduction techniques may be needed to reduce radon levels to below the Canadian guideline.
A certified radon professional will likely perform one or more diagnostic tests to help determine the best radon-reduction system for your home. For example, your contractor may use chemical smoke to see the air flow sources and radon entry points by watching a small amount of smoke that has been placed into holes, drains, sumps or along cracks. Another type of diagnostic test is a Pressure Field Extension Test (or communication test). This test uses a vacuum cleaner (e.g., a Shopvac) to measure how easily air can move from one point to another under the foundation and estimate the number of suction points and fan size needed for an active radon-reduction system.
Sub-slab depressurization (also called active soil depressurization) is the most effective and reliable radon reduction technique. It is also the most common method used by C-NRPP certified professionals. This method involves installing a pipe through the foundation floor slab and attaching a fan that runs continuously to draw the radon gas from below the home and release it into the outdoors where it is quickly diluted. This system also reverses the air pressure difference between the house and soil, reducing the amount of radon that is drawn into the home through the foundation. One, or sometimes multiple, suction points are inserted through the floor slab into the crushed rock or soil underneath to effectively reduce the radon level in the home.
The sub-slab depressurization pipe can be vented at either the roof level or ground level of the home. The fan can be placed in the basement or an area outside of the living space such as in a garage or attic. If the fan is placed inside the living space of the home, it is usually vented sideways through the rim joist at ground level, with the fan close to the exhaust location. When the fan is placed outside of the living space (e.g. attic or garage) then it is typically vented upwards above the roof.
In many Canadian climates, a fan and pipe located outside the living space (garage or attic) will cool during the colder months of the year, leading to condensation and possibly ice, which can damage the fan and affect the effectiveness of the radon-reduction system.
Condensation problems can be reduced if the fan is placed indoors and the exhaust is discharged from a shorter pipe near ground level at right angles to the wall, much like the power vented exhausts from combustion appliances such as natural gas-fired water heaters.
If the fan is placed inside the home, it is important to confirm with your contractor that it is air tight and that all pipes and plumbing joints have been sealed. Properly installed fans and pipes will not leak radon into the building and are usually installed in the basement. When the fan and pipe are placed inside the home and combined with a ground level discharge, almost the entire system is located indoors, which helps to avoid problems that can arise from cold climates.
Current field test studies of indoor mounted fans with near ground level discharges show this is an effective technique. Further field testing of this system in urban environments where houses are built in close proximity to each other is necessary. To verify continued performance of any radon-reduction system, an initial long-term measurement should be made within two years of the system activation and at two-year intervals afterwards.
Without testing you cannot know. All houses have the potential to have Radon especially in areas where high concentrations have been proven.
There are some measures that can be taken, such as sealing cracks on foundation and slabs but Radon can still come through sump pumps and floor drains. This is why Radon mitigation concentrates on removing the Radon.
Although there is a cost attached to Radon mitigation, the benefits outweigh the costs.
Radon exists in the exterior environment naturally and having windows open during the test, will affect the results.
A short term test is the first step. If high concentrations are noted during the short term test then we highly recommend having a long term test, typically 3 months) to see how the levels of Radon fluctuate. Radon levels can be affected by seasonal factors therefore a long term test is more accurate.
There are multiple cheap devices sold in the retail market but none are accredited and calibrated, therefore the results will not be accurate.