Radon-resistant construction is worth discussing before foundation work, but a newly built home in Colorado can still have elevated radon. Ask the design and construction professionals which features suit the project, confirm the approach with the local building department, and plan to test the completed home. A map or installed passive system cannot tell you the radon level inside that individual home.
Radon is a naturally occurring gas that can move from soil and rock into buildings. The Colorado Geological Survey and EPA provide public information about radon, testing, and mitigation. These sources can inform a radon-resistant construction conversation, but a regional map is not a measurement of a particular house. The only way to know the level in a finished home is to test it.
Why discuss radon before construction?
Some radon-resistant features are integrated with below-grade construction. Raising the question while the foundation and building details are still being coordinated gives the project team a chance to consider how the approach fits the selected foundation, site conditions, and applicable requirements. It is a planning conversation—not a substitute for a radon professional’s advice or the authority having jurisdiction.
The U.S. Environmental Protection Agency describes common radon-resistant approaches that can include a gas-permeable layer, a gas-retarding membrane, sealed openings, and a vent path that can be adapted if active ventilation is later needed. The exact elements and configuration vary with the foundation, site, adopted code, and current technical standards. Ask the qualified project professionals to determine what applies rather than treating a general article or diagram as a construction specification.
For broader property questions, see the Colorado land due-diligence guide and what a Colorado soils report can reveal. A soils report and a radon test answer different questions; neither should be substituted for the other.
What should you ask the project team?
Bring the topic to the architect or other design professional and the builder while the foundation and mechanical plans are being coordinated. Depending on the project, a qualified radon professional may also be appropriate. Useful questions include:
- What does the local building department require or recommend for this property and foundation type?
- Which current code provisions or recognized technical standard will guide the proposed approach?
- What features are included in the drawings and specifications, and who verifies they are installed as designed?
- If the system is passive, what provisions would make later activation feasible if testing indicates it is needed?
- How will the vent route, roof penetration, electrical provisions, and future access be coordinated with the design?
- When and how should the finished home be tested, and who can perform that test?
- What records, operating instructions, and follow-up steps will be provided to the homeowner?
These are conversation prompts, not a design checklist. Foundation details, vent routing, penetrations, pressure relationships, and electrical work belong with the professionals responsible for the plans and installation. Concierge’s public Process describes its project-stage Site Analysis as considering orientation, views, access, utilities, and constraints; that does not establish a separate radon-review, testing, or mitigation service.
What does radon-resistant construction include—and does it remove the need for testing?
No. A radon-resistant feature is intended to help limit radon entry; it does not certify the indoor level. EPA advises testing new homes, including homes with radon-resistant construction features. Follow the test device instructions and use a qualified measurement professional when the project or applicable requirements call for one.
EPA identifies 4 picocuries per liter (pCi/L) as its action level for fixing a home. EPA also notes that radon levels below 4 pCi/L still carry some risk and may be reduced. Do not interpret the action level as a guarantee of zero risk, and do not decide on a mitigation design from this article. If a result raises concern, consult the state radon program and an appropriately qualified radon professional.
What can a map tell you—and what can it not tell you?
Maps and regional geology can help explain why radon belongs on the project’s question list. They cannot determine the concentration inside one future home. Radon can vary from building to building, including among nearby homes. A map is context; a test is the measurement.
If you are still evaluating land, the live Buying Land in Colorado guide is a useful next step for organizing broader due-diligence questions. For details on how site information enters Concierge’s project process, see Site Analysis and the Process page.
A short planning checklist
Before foundation work advances, make sure the project record answers these questions:
| Question | Who can confirm it |
|---|---|
| What radon-related provisions apply to this project? | Local building department and design professional |
| What features are actually included in the plans and specifications? | Responsible design professional and builder |
| Who will verify installation and keep the relevant records? | Project team, as established in the project documents |
| How and when will the completed home be tested? | Qualified radon measurement professional and project team |
| What happens if the result is elevated? | Qualified radon mitigation professional and homeowner |
Keep answers tied to the current project documents. Requirements can differ by jurisdiction, and a professional should confirm the current rules for the actual site.
Frequently asked questions
Can a new Colorado home still have radon?
Yes. New construction does not prove that indoor radon is absent. Regional information can guide planning, but only testing can measure the finished home.
Does radon-resistant construction guarantee a safe reading?
No. The features are designed to reduce entry, not to certify an indoor concentration. Test the completed home and ask a qualified professional about any result that needs follow-up.
When should a new home be tested for radon?
EPA recommends testing a new home after construction, even when radon-resistant features were included. Follow the test method’s instructions and any applicable local requirements.
Can a soil or geology map tell me the radon level at my house?
No. Maps indicate regional potential, not the result for one property or home. A radon test is needed for that.
Do all Colorado jurisdictions require the same radon system?
Do not assume that they do. Ask the local building department and the professionals responsible for the project which current requirements apply at the specific site.
Radon information here is general education, not medical, testing, mitigation, engineering, or code advice. Have a qualified radon professional and the appropriate project professionals confirm the method and current requirements for the actual home.
To learn how Concierge’s published project process is organized, visit the Process page. If you would like to discuss a project, Book a Discovery Call.
