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periodic table background for radon inspection











What is Radon?

Radon is an odorless, invisible gas that occurs naturally when uranium breaks down in the soil. It can penetrate any building through the concrete slab, basement, or crawl space and cause severe lung damage with long-term exposure. According to the EPA, it is the leading cause of lung cancer among non-smokers. While dangerous, it is avoidable with radon mitigation and abatement. The only way to know if there is radon present in a structure is to test for it.

When to test?

All homeowners should test their homes for radon. Radon is in all 50 states and all types of houses, so it is impossible to predict which homes are safe without conducting a test.

Home buyers should add professional radon testing to their home inspection. When results show elevated levels of radon, steps can be taken to negotiate for radon mitigation or adjust the sales price to cover those repairs before closing.

Home sellers should also test their home for radon when preparing to sell. Proactive steps can be taken to mitigate radon and avoid delays in the home selling process.

Who's at risk?

Radon Zone 1 (Highest Potential)

Radon Zone 2 (Moderate Potential)

Radon Zone 3 (Lower Potential)

Radon has been found in buildings in all 100 counties in North Carolina.  Certain portions of the state have a higher potential for radon as indicated on the following map.  Other contributing factors include:

  • Foundation Type: Dirt floors in the basement, like those in older homes, have nothing to slow the rise of radon gas from the soil. Exposed crawl spaces also allow radon to easily rise into living areas 

  • Foundation Damage: Radon can seep through concrete, however cracks in foundation slabs and walls make it easier for extra radon gas to enter the home.

  • Construction Gaps: Any gap in the foundation can allow radon to enter the home. These include gaps around pipes and wires, construction joints where walls and floors meet, open sump pumps, to list a few.

  • Well Water: Groundwater can also contain radon. Well water should be tested yearly for contaminants, including radon.

map indicating radon risk potential in North Carolina

Testing Types

DIY Radon Test kits are available at most home improvement stores, however they are not as accurate as the test conducted by professional inspectors.  Not only is the professional testing equipment better, but test placement is a key step to an accurate test. 


Continuous Radon Tests are conducted through sophisticated electronic devices that measure radon concentration over 48 hours.  Each device must be placed in the home strategically, based on the home configuration. The device will monitor the radon levels over 48 hours while reducing or eliminating interference that can result in false or inaccurate results. The inspector will collect the device after 48 hours, and provide a report based on the measurements taken by the state-of-the-art tamper-resistant radon detector.

Long-term Radon Tests tend to be more accurate because they use a different detection method for radon levels. These tests also collect data for a period of three months to a year. This type of test is usually recommended for homes in high risk regions.

Test results

Though no level of radon is considered safe, the EPA has established guidelines for acceptable levels. If your test indicates Radon levels at 4 pCi/L or higher, you should take radon abatement and mitigation measures to reduce the amount of gas in your home and lower your risk for radon-related health problems.  Action may not be needed as urgently if your radon levels are between 2 and 4 pCi/L, but you should still consider taking steps to lower the levels.

Next steps

If radon is identified in your home, you should take steps to reduce the radon levels. To begin with, cracks in walls and floors can be sealed with caulk or plaster.  In addition, you can get a radon mitigation system installed which uses pipes and fans to remove the gas from beneath the foundation before it can enter your home.

The cost for a radon mitigation system can range between $800 and $1500, depending on your home’s design, size, foundation, construction quality, and climate.  

For more information regarding radon visit:  Environmental Protection Agency ;  NC Department of Health and Human Services ; EPA Homebuyers & Sellers Guide To Radon

Protect Your Health & Home

Don't take chances with your health,  schedule a radon test or add one to your home inspection with Black Cat Inspection Services. 


For reliable service, and hassle free testing SCHEDULE ONLINE.

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