New Construction and Radon - Radon is a natural gas that comes from uranium in soil and rock. You cannot see it or smell it. But it can build up inside a home and raise the risk of lung cancer. In Colorado, radon is common, and the Denver area is known for higher levels because of local geology. The good news is that in a new home, radon protection is much easier and cheaper to build in from the start.
Why radon matters in new construction
When a house is built, it sits on a foundation that touches the ground. Tiny cracks can form as concrete cures and settles. Gaps can also appear around sump pits, plumbing lines, and floor joints. Radon moves through the soil and can slip into these openings. In winter, Denver homes are often closed up tight to keep heat in. That can trap radon inside.
Testing is the only way to know a home’s radon level. Many people assume a brand-new home is “clean,” but new does not mean radon-free. Two houses next to each other can have very different readings. That is why building with protection in mind is so important.
What a radon-resistant new home includes
A radon-resistant system is not complicated. It is a set of smart steps that help prevent soil gases from entering the living space.
- Gas-permeable layer: Builders often place a layer of gravel under the slab. This creates space for radon to move to one location instead of pushing up through the concrete.
- Plastic sheeting: A durable vapor barrier over the gravel helps block soil gases and moisture.
- Sealing and caulking: Sealing cracks and openings in the slab and foundation is not enough by itself, but it supports the system.
- Vent pipe (passive system): A PVC pipe runs from beneath the slab up through the house and out the roof. This gives radon a path to leave the home.
- Electrical rough-in for a fan: If a test later shows higher radon, a fan can be added easily to turn the system “active.” Active systems pull radon from under the house and vent it outside.
Denver-area considerations
When considering new construction and radon, the Front Range has many areas with elevated radon potential. Homes with basements can have more contact with soil, which can increase risk. Also, energy-efficient construction is popular in the Denver market. Better insulation and tighter sealing help with comfort, but they can also reduce fresh air exchange, which can allow radon to build up. That does not mean energy-efficient homes are unsafe. It means radon control and ventilation planning should be part of the design.
What homeowners and builders should do
If you are building a home, ask early about radon-resistant features. If the builder already includes a passive system, request an electrical rough-in so adding a fan is simple if needed. After you move in, test the home. The best time is during colder months when windows stay closed, but testing any time is better than not testing.
A radon-resistant new construction plan is a practical safety upgrade. In the Denver area, it is one of the smartest ways to protect a household from a risk you cannot detect without testing. (New Construction and Radon)
