If a test comes back at or above the action level the EPA publishes, the remedy is well established and unexciting, which is exactly what you want in a building repair. The standard approach is sub-slab depressurization. A contractor creates a suction point beneath the concrete, runs a sealed pipe from that point to a discharge above the roofline, and puts an inline fan on the pipe. The fan holds a slight negative pressure under the slab, so soil gas moves into the pipe and out above the house rather than up through the floor.
This is a routine installation rather than a renovation. It does not require tearing out floors, and in most houses the visible result is a length of pipe, a fan, and a small gauge on the pipe. What matters more than the hardware is the diagnostic work before it and the verification after it: finding where suction actually travels under the slab, and re-testing once the system runs so that the fix is confirmed by a measurement rather than assumed.
The contractor examines the foundation and often runs a communication test, checking how far suction travels under the slab from a candidate point. That determines whether one suction point is enough or more are needed.
The slab is cored, material is removed beneath it, and pipe is run from that cavity along the chosen route to a discharge above the roofline, with every joint sealed as it goes.
An inline fan sized to the conditions is installed outside the living space, wired properly, and set to run continuously. The gauge is mounted where you can actually see it.
Openings that would short-circuit the suction are sealed, the system runs, and a fresh test confirms the result. A system that has not been re-tested has not been finished.
Mitigation quotes vary because houses vary. House footprint and foundation type lead: a compact slab is a different job than a sprawling one, and a house with both a slab and a crawl space may need each addressed. Routing matters a great deal, since a straightforward run through a utility space to the roofline is simpler than a long exterior route around a finished home. Fan sizing follows the soil and sub-slab material. Whether an existing sump or drain tile can be used as the suction path can simplify the work. Number of suction points, sealing scope and the post-installation re-test round it out. Ask for a written scope.
A properly installed system is quiet. The fan is mounted outside the living space and produces a low steady hum, and there is some air movement noise in the pipe. Placement is part of the design: a fan mounted next to a bedroom wall will be noticed, and a good contractor plans the route with that in mind. If a system becomes audibly louder over time, that is worth a service call.
No. Sealing is a supporting measure, not the fix. Cracks, the joint where the foundation meets the floor, sump openings and utility penetrations are sealed so the fan is not wasting its pull on the easiest openings, but sealing alone is not a reliable way to bring a level down. The pipe and fan do the work, and sealing helps them do it efficiently.
That is common and it is handled. The slab area is addressed with a suction point beneath the concrete, and the crawl space is typically covered with a sealed membrane that the system draws from, so both parts of the floor are treated. Sometimes one fan serves both through a shared pipe run, and sometimes the layout calls for separate points. Diagnostics decide.
By measuring again. Once the system is running, a fresh test tells you what the house is doing now, and that result is the actual proof of performance. Anything else is inference. Ask the contractor whether a post-installation test is included in the scope and who reads it, and keep the before and after results together with the system paperwork.
Everything begins with a measurement. A contractor places a short-term device for a quick reading or a long-term device for a closer look at your yearly average, then hands you a number you can make a decision from.
Learn more →A sale runs on its own clock. Radon tests during a transaction carry timing rules and closed-house requirements, and it saves friction to settle early who orders the test and who deals with the result.
Learn more →Fans do not run forever, and the little monitor on the pipe is easy to stop noticing. Service means checking that gauge, confirming the fan still pulls, replacing it at end of life, and re-testing to prove the system still works.
Learn more →During a build, the pipe can be run before the drywall closes the walls. A passive rough-in is far simpler than routing a system through a finished house, and adding a fan later is a small job.
Learn more →County, foundation type, and whether a deadline is involved is enough to start.