Does Sealing Concrete Reduce Radon: 6 Factors [To Consider]

Last Updated on February 6, 2023

Radon gas is a natural radioactive gas that is odorless, colorless, and tasteless but can be deadly in high levels. It’s found in the soil and is released into the air when it seeps into your home through unsealed concrete floors or walls.

Fortunately, there are measures you can take to reduce radon levels in your home, such as sealing your concrete surfaces with an appropriate sealer. In this blog post we discuss what you need to know before beginning a sealing project, the procedure for applying sealer to concrete surfaces, and potential benefits of sealing against radon exposure. 

Sealing Concrete and How it Reduces Radon Levels 

Considerations Before Beginning a Sealing Project

Type of Sealer to Use 

When undertaking any sealing project, it is important to consider the type of sealer that will be used. For concrete surfaces, there are two main types of sealers; penetrating and topical.

Penetrating sealers such as silanes and siloxanes are designed to penetrate deep into the pores of the concrete surface, creating an invisible barrier that helps to prevent water and other liquids from entering the surface and causing damage.

This type of sealer can also help reduce radon levels. Topical sealers provide a layer of protection on top of the concrete, providing a barrier against moisture while also providing protection against dirt, grime, and other contaminants. They come in various forms such as acrylics, epoxies, polyurethanes and polyaspartics for added protection against ultraviolet light, chemical spills and humidity.

Appropriate Conditions for Sealing

In addition to choosing the correct type of sealer for a given project, it is also important to ensure that conditions are appropriate for sealing. Ideally, the temperature should be between 50-80°F (10-27°C) when applying any kind of sealant or paint product to concrete.

Additionally, moisture levels should not exceed 5% within 24 hours prior to application in order for the product’s adhesion properties to remain effective over time. With regard to radon reduction specifically, it is important that there be an airtight seal around windowsills and between foundation walls and flooring in order for any form of radon mitigation system including sealing to work effectively over time.

It is also important to ensure that any gaps or cracks in concrete surfaces are filled before commencing with any sealing process in order for them not to become entry points later on down the line.

Procedure for Applying Sealer to Concrete Surfaces

Cleaning the Surface Before Application 

Before applying sealer to concrete surfaces, it is important to clean the surface thoroughly. This step ensures that the sealant adheres properly and creates a strong bond with the concrete.

Depending on the condition of the surface, a variety of cleaning methods can be used. The most effective method is pressure washing, which removes dirt, debris, and any contaminants that could prevent proper adhesion of the sealant. If intense pressure washing is not necessary or possible, then scrubbing with a wire brush or power tool can also be used in order to remove smaller amounts of dirt and grime.

If mold is present on the surface or if there has been an oil/fuel spillage, then special detergents should be used in order to ensure complete removal from the surface before applying sealer. 

Measurement and Marking Where the Sealer Should Be Applied

Once the concrete surface has been cleaned and prepared for sealing, it is necessary to measure and mark where exactly the sealer will be applied. This helps to ensure that all parts of the concrete are properly covered with an even layer of sealant.

It is also important to understand how much area needs to be sealed in order to purchase enough product to cover it without wastefulness or oversaturating any particular area. By measuring and marking beforehand, one can avoid any mistakes when it comes time for actually applying sealer over the entire area. 

Applying the Sealer in Even Coats with a Brush or Roller 

After having measured and marked where exactly each coat will go, one can now start applying the sealant itself over these areas using either a brush or roller as desired. It is important that each coat is applied evenly so as not to saturate any particular area more than another while also ensuring that no areas are missed completely.

One may need multiple coats depending on manufacturer instructions of how many layers are required for best results–typically two coats are needed but this may vary depending on product used.

Taking extra care during this process helps create an optimal bond between sealant and concrete which increases longevity of protection against wear-and-tear from weather elements such as snow and rain; this also helps protect against harmful gasses like radon from entering buildings through cracks in flooring and walls made from concrete substrates such as cinder blocks or foundations due said protective barrier being formed by correctly applied layers of sealant .  

Waiting Period before Applying a Second Coat (if Necessary) 

Once one has finished applying their first coat of sealant, it is important (if applicable) to allow a designated waiting period before applying another coat; this period varies based on manufacturer instructions but typically ranges anywhere between 30 minutes up to several hours depending on product type used as well as temperature conditions during application period (i.e., colder temperatures requiring longer waiting periods).

Allowing ample time between coats enables maximum penetration into pores within concrete substrates which further strengthens protection from wear-and-tear from environmental elements mentioned previously but even more importantly–protects against harmful radon gas levels entering buildings due said gases’ inability penetrate said protective barriers formed by correctly applied layers of sealant .

Potential Benefits of Sealing Concrete Against Radon Gas Exposure

When radon gas is present in a home, sealing concrete can provide many potential benefits. This includes protection from water penetration and moisture buildup in basements or crawlspaces, reduction of indoor air pollutants such as dust, mold, mildew, VOCs, and pesticides, as well as prevention of soil gases containing radon from leaking into dwellings through cracks or holes in floors or walls. 

Protection from Water Penetration and Moisture Buildup in Basements and Crawlspaces 

One of the most important benefits offered by sealing concrete against radon gas exposure is protection from water and moisture infiltration. As moisture enters the basement or crawlspace through cracks in the floor or walls, it builds up over time to create an unwelcome environment for fungi and other organisms that thrive on wet surfaces.

Additionally, moisture can cause damage to property stored in these areas by encouraging mold growth and corroding metal items. By sealing concrete correctly with a high quality sealer, surface water can be prevented from entering the area while also offering a protective layer against any remaining air-born moisture content. This helps to keep basements dry and reduce incidents of health hazards associated with dampness such as asthma attacks caused by mold spores. 

Reduction of Indoor Air Pollutants Such as Dust, Mold, Mildew, VOCs, and Pesticides 

In addition to protecting against water penetration and moisture buildup in basements and crawlspaces, sealing concrete against radon gas exposure can also help to reduce indoor air pollutants. Sealing concrete forms an impermeable barrier between interior spaces such as living rooms or bedrooms which are susceptible to airborne contaminants like pollen particles or dust mites; thus preventing them from entering the home altogether.

Furthermore, sealing can also help protect against volatile organic compounds (VOCs) released by paint fumes or pesticides used inside the house which are known to pose serious health risks when inhaled over a long period of time.

Finally, mold growth often occurs due to excessive humidity within enclosed spaces; however this can be greatly reduced by sealing concrete effectively since it helps maintain lower relative humidity levels throughout the building envelope which discourages fungal growth altogether. 

Prevention of Soil Gases Containing Radon From Leaking Into Dwellings Through Cracks or Holes in Floors or Walls 

One of the most important aspects about sealing concrete against radon gas exposure is that it helps prevent soil gases containing traces of radioactive material from entering our homes through cracks or holes in floors or walls.

Radon gas is a naturally occurring element found underground which gradually rises up into dwellings if not properly sealed off at its entry point(s).

According to Health Canada’s website “It is estimated that radon causes about 16% of all lung cancer deaths related to environmental factors” making it a very real danger for individuals exposed over long periods without proper protection measures taken beforehand such as effective structural seals around windows & doors; caulk & weather strips around doorways; sump pumps; dehumidifiers; etc.

By ensuring all possible areas where soil gases containing radon could enter are properly sealed with high quality sealers made specifically for this purpose we can greatly reduce our risk factor for developing potentially fatal illnesses associated with this hazardous material.

Potential Implications for Public Health

Potential Implications for Public Health

Increase in Lung Cancer Risk from Radon Exposure

Radon is an odorless, colorless, radioactive gas that can enter indoor spaces due to the natural breakdown of uranium found in soil and rock. Inhaling radon can increase the risk of developing lung cancer, making it a major public health concern.

According to the United States Environmental Protection Agency (EPA), radon is the leading cause of lung cancer for those who do not smoke. The EPA has set action levels for indoor air radon levels that are considered safe; when levels exceed 4 picoCuries per liter (pCi/L), individuals should take steps to reduce their exposure.

The consequences of radon exposure may be especially concerning because individuals cannot detect when they are exposed to dangerous levels. Radon gradually accumulates indoors so individuals living in homes with high radon levels may not ever know they are at risk until health complications occur much later on down the line.

Thus, it is important for individuals and families to be proactive about testing their home’s air quality and taking measures to reduce any potential risks associated with high radon levels such as proper ventilation or sealing projects. 

Role of EPA Guidelines for Improving Indoor Air Quality through Sealing Projects 

One crucial way to reduce the long-term risk of radon exposure and its subsequent health effects is through implementing sealing projects in order to prevent more indoor accumulation over time.

Sealing projects can include closing up foundation cracks and installing plastic barriers over floors near walls where gas can seep in from outside sources like soil or rock structures.

All sealing projects should follow recommendations outlined by the EPA in order to ensure maximum protection from potentially harmful gases like radon. 

These guidelines also provide information about how other contaminants like mold spores, carbon monoxide, volatile organic compounds (VOCs), lead dust particles, asbestos fibers, dust mites, pet dander and pollen particles can enter indoors as well and how best to guard against them.

For instance, properly sealed windows or doors can help protect against airborne allergens like dust mites; installing carbon monoxide detectors near potential sources such as furnaces or water heaters can alert occupants if dangerous levels accumulate; and investing in quality ventilation systems ensures fresh air flows throughout a space while removing common pollutants before they become concentrated inside a home environment.

Health Impacts that Can Arise from DIY Sealing Projects Performed Incorrectly 

While DIY sealing projects may seem like an inexpensive solution for improving indoor air quality, performing these tasks incorrectly can create even larger problems than doing nothing at all for public health purposes.

When performed correctly under EPA guidelines by licensed contractors familiar with local building codes, DIY sealing solutions have been found effective at reducing long-term radiation exposures from both natural sources such as soil or rock formations as well as manmade ones such as imported building materials containing higher concentrations of uranium-based compounds than those found naturally occurring in certain regions.

However, incorrectly installed sealants create pathways that allow even more gases into buildings than before the project began in addition to trapping existing toxic gases inside already present within a structure’s walls or foundation during renovations.

This means any inhabitants may then be exposed to heightened concentrations of hazardous materials without knowing it until serious health concerns arise much later on down the line due to prolonged period of low-level but ongoing small exposures over time.

Therefore practicing caution when undertaking any type of project dedicated towards improving indoor air quality is key since mistakes made during installations can have significant negative impacts on personal wellbeing further down the line that only become noticeable once damage has already been done.

How do you seal cracks to prevent radon?

How do you seal cracks to prevent radon

Sealing cracks and other openings in the concrete foundation of a building is one of the most effective ways to reduce radon levels. This is because sealing off any potential paths for radon gas to enter the living spaces will help to prevent it from accumulating.

The process of sealing cracks and other openings typically involves using caulk or expanding foam, although specialized products designed for use with concrete can also be used, such as polyurethane-based sealant. Once applied, these sealants should be checked periodically and reapplied as needed in order to maintain their effectiveness over time.

Does the concrete slab stop radon?

While sealing gaps in the basement/foundation may reduce radon levels within the home, it does not completely stop them. This is because radon is a naturally occurring gas that exists all around us, so even if all visible sources of entry are blocked, some levels will always exist. However, by reducing the amount that enters through large cracks or gaps in walls or floors, overall levels should decrease significantly. 

How do you mitigate radon on a slab?

Mitigating radon on a slab involves taking additional measures beyond just sealing cracks and holes. One option is to install an air filtration system that collects particles from the air before they pass into interior living spaces; this method helps capture both radon particles as well as airborne dust and allergens too.

Other methods include installing impermeable membranes beneath slabs (such as asphaltic membranes), injecting gasses into soil under slab foundations (such as nitrogen) and improving ventilation of crawl spaces and basements (by adding fans or vents). All of these techniques can help reduce indoor radon levels and improve air quality inside homes. 

Can you seal out radon?

Yes, you can seal out some types of radon by blocking its entry points into your home; however it cannot be completely eliminated as it exists naturally in outdoor air too. Therefore while sealing off potential sources of entry can help greatly reduce indoor radon levels, it cannot completely remove them altogether; other mitigation techniques such as those mentioned above must also be used in order to achieve this goal.


Sealing concrete surfaces is one of the most effective ways to help protect your home from radon gas exposure. Not only does it reduce air pollutants like dust and mold but it also prevents soil gases containing radon from entering dwellings through cracks.

When selecting a sealer for this task make sure you consider the type of sealer needed, appropriate conditions for application as well as any additional protective measures that may need to be taken during installation. Sealing your concrete surfaces is an easy step towards improving indoor air quality and protecting you and your family from potentially dangerous radon levels in your home.

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