Radon, Remodeling, and Lung Health: A Denver Warning

By Franklin Everett Shaw

January 27, 2026

Are you about to tear down that wall in your Denver bungalow? Hold up. Before you swing that sledgehammer, let’s talk about something you can’t see, smell, or taste, but could be silently jeopardizing your health: radon.

Radon, a naturally occurring radioactive gas, is the second leading cause of lung cancer in the United States. Denver, with its unique geological makeup and abundance of older homes, is a hotspot for elevated radon levels. Renovations, while improving your home’s aesthetics and value, can inadvertently disrupt existing radon mitigation systems or, worse, expose previously undetected radon sources. This is especially critical in older neighborhoods like Wash Park, where housing stock often predates modern radon awareness and mitigation practices.

Ignoring radon during a remodel is like playing Russian roulette with your family’s health. It’s a gamble you simply can’t afford to take.

So, how do you protect yourself and your loved ones? Let’s dive into the specifics of radon and renovations in Denver, providing you with actionable steps to ensure a safe and healthy home.

First, understand the problem. Radon is produced by the natural decay of uranium in soil, rock, and water. It seeps into homes through cracks in foundations, gaps around pipes, and other openings. Denver’s geology, particularly the presence of uranium-rich shale, contributes to higher radon levels compared to many other regions. Older homes, common in neighborhoods like Wash Park, Highlands, and Capitol Hill, are particularly vulnerable due to their aging foundations and less stringent building codes at the time of construction.

Renovations can exacerbate the problem in several ways. Demolition can create new pathways for radon to enter the home. Sealing off certain areas during construction can alter air pressure, potentially drawing more radon into other parts of the house. Even seemingly minor changes, like adding a new bathroom in the basement, can disrupt existing ventilation patterns and increase radon concentrations.

What about homes that already have radon mitigation systems? Don’t assume you’re safe. Renovations can damage or compromise these systems. For example, relocating a sump pump during a basement remodel could render the entire system ineffective. It’s crucial to have your mitigation system inspected and re-certified after any significant renovation.

Here’s your pre-renovation checklist:

• Test, test, test: Even if you’ve tested your home for radon in the past, do it again before starting any renovation. Conditions can change over time. Use a short-term test kit for a quick assessment, but follow up with a long-term test for a more accurate reading. You can find radon test kits at most hardware stores or online. The Colorado Department of Public Health and Environment (CDPHE) also provides resources and information on radon testing.
• Review existing mitigation systems: If you have a radon mitigation system, locate all its components (fan, piping, etc.) and carefully consider how the renovation might impact them. Consult with a qualified radon mitigation professional before starting any work that could affect the system.
• Plan for mitigation: If your pre-renovation test reveals elevated radon levels, incorporate radon mitigation into your renovation plans. This is often more cost-effective than retrofitting a system after the fact. Consider installing a passive sub-slab depressurization system during the renovation, which can be easily activated later if needed.

Now, let’s talk about post-renovation testing. This is non-negotiable. Even if your pre-renovation test was negative, or you had a mitigation system in place, you must retest after the renovation is complete.

Here’s your post-renovation checklist:

• Test immediately: Wait at least 24 hours after the renovation is complete to allow dust and debris to settle. Then, conduct a short-term radon test.
• Verify mitigation system functionality: If you have a mitigation system, have it inspected by a certified radon mitigation professional to ensure it’s functioning correctly. They can check the fan, piping, and other components to ensure they haven’t been damaged or compromised during the renovation.
• Take action: If your post-renovation test reveals elevated radon levels, contact a certified radon mitigation professional to discuss your options. Mitigation typically involves installing a sub-slab depressurization system, which draws radon gas from beneath the foundation and vents it safely outside.

Finding a qualified radon mitigation professional in Denver is crucial. The CDPHE maintains a list of certified radon professionals in Colorado. Look for someone who is certified by the American Association of Radon Scientists and Technologists (AARST) or the National Radon Proficiency Program (NRPP). Don’t just go with the cheapest option; prioritize experience and qualifications.

Common mistakes developers make include:

• Ignoring radon altogether: This is the biggest and most dangerous mistake.
• Assuming a previous test is still valid: Radon levels can change over time due to soil shifts, weather patterns, and other factors.
• Damaging or compromising existing mitigation systems without realizing it: Be extra careful when working around pipes, fans, and other components of the mitigation system.
• Failing to retest after the renovation: This is essential to ensure that the renovation hasn’t increased radon levels.
• Hiring unqualified contractors: Make sure your contractor is experienced in working with radon mitigation systems.

Overcoming these challenges requires awareness, planning, and a commitment to safety. Educate yourself about radon and its risks. Incorporate radon testing and mitigation into your renovation plans. Hire qualified professionals. And always, always retest after the renovation is complete.

Let’s consider a real-world scenario. Imagine you’re renovating a Victorian-era home in Wash Park. During demolition, you discover cracks in the foundation that were previously hidden behind drywall. This is a red flag. These cracks could be a major entry point for radon. Before proceeding, conduct a radon test. If the results are elevated, consider installing a sub-slab depressurization system as part of the renovation. This will not only protect your family’s health but also increase the value of your home.

Another example: You’re adding a new bathroom in the basement of your home in Stapleton. The plumbing work requires you to relocate the sump pump, which is also part of your existing radon mitigation system. Before moving the sump pump, consult with a certified radon mitigation professional. They can advise you on how to relocate the sump pump without compromising the effectiveness of the mitigation system. After the bathroom is complete, have the system inspected and re-certified.

Radon mitigation isn’t just about protecting your health; it’s also about protecting your investment. A home with a radon mitigation system is more attractive to potential buyers. It demonstrates that you’ve taken steps to ensure the safety and well-being of your family.

Don’t let radon be an invisible threat lurking in your Denver home. Take control of your health and protect your family by testing for radon before and after any renovation. With a little planning and effort, you can create a safe and healthy living environment for years to come. Remember, knowledge is power, and in this case, it could save your life.