Healthy homes
Radon and a new Eastside home: what to decide before construction
Radon is invisible and odorless. The easiest time to make a house ready for mitigation is while it is being built, before the slab, walls, and mechanical systems are finished.
On this page3 sections
Start with testing and local information
Radon levels can vary from house to house. A map can show regional patterns, but it cannot tell you the level in a specific finished home.
Washington’s Department of Health explains testing, health risks, and radon-resistant construction on its radon information page.
Make future mitigation easy
- Discuss a gas-permeable layer and sealed slab penetrations.
- Plan a vent pipe route from below the slab to above the roof.
- Provide an accessible location and electrical connection for a future fan.
- Test after the home is enclosed and occupied, then mitigate if needed.
Coordinate it with the plans
Ask the architect and mechanical team to show the intended route and details. A small amount of planning now can avoid opening walls later.
Action plan
Make the home radon-ready
- 1
Review Washington’s radon map for context, but do not use it as a substitute for testing the finished house.
- 2
Ask the architect to show the below-slab gas layer, sealed penetrations, vent route, roof termination, fan location, and nearby power source.
- 3
Keep the vent route away from windows and coordinate it with plumbing, structure, and mechanical shafts.
- 4
Test the lowest regularly occupied level after construction under the kit or professional’s instructions.
- 5
If results are elevated, activate or improve mitigation and retest to confirm the result.
Official resources