What happens during a radon mitigation installation
Most single-family radon installations are a one-day job for a two-person crew, and the disruption is closer to a plumbing repair than a renovation. Knowing the sequence makes the day easier to plan and makes it obvious when something is being skipped.
Here is what actually happens, roughly in order.
Before anyone drills: the walkthrough and diagnostic
The crew confirms the design against the house: where the suction point is going, where the pipe will run, where the fan will sit, and where the discharge terminates. This is your last easy opportunity to move a pipe route away from a room you plan to finish, so speak up now.
If a pressure-field test was not run at the estimate, it should happen here — a small test hole, applied suction, and readings at points across the slab to confirm that one point covers the footprint.
Coring and the suction pit
A core drill cuts a hole through the slab, typically four to six inches across. This is the loudest part of the day and generally the dustiest; good crews use vacuum attachment and containment, and it usually lasts under an hour.
Beneath the hole, the crew excavates a small pit — often a five-gallon bucket of material or more — to create a plenum. That void is what lets the fan draw from a wider area instead of just the hole itself, and it matters a great deal on tight sub-slab material.
Pipe, routing, and sealing
The riser is set into the cored opening and the annulus around it is sealed. Pipe runs from there along the intended path — through a chase or closet to the attic, or out through a rim joist or wall to an exterior elevation — supported as it goes.
Sealing happens alongside: floor-wall joint, visible cracks, open penetrations, and a gasketed lid on any sump pit. On block foundations the top course may be sealed as well. This is unglamorous work and it is a large part of what you are paying for.
Fan, electrical, and discharge
The fan is mounted outside conditioned space and wired — sometimes by the crew, sometimes by an electrician, which should have been settled in the quote. The discharge is run to terminate above the eave, away from windows and other openings.
A manometer is fitted on the riser at this stage. Once power is on, you will hear air movement, and the manometer fluid should sit at uneven heights showing the system is pulling.
Commissioning and cleanup
The crew walks the finished system with you, labels it, and hands over documentation. Expect the written scope, the warranty, and a scheduled post-mitigation verification test — that test needs the system to have run at least twenty-four hours, so it happens after the crew has gone.
Cleanup should return the space to how they found it, minus the core dust. What is left behind is a pipe, a fan, a gauge, and a pending measurement.
What happens during installation: common questions
Do I need to be home for the installation?
For the walkthrough at the start, yes, if at all possible — that is when routing and discharge placement are decided. For the middle of the day, no. Many homeowners attend the opening walkthrough and the closing commissioning and leave the crew to work in between.
How messy is core drilling?
It produces concrete dust and slurry, but it is contained work. Crews normally use vacuum attachment and sheeting, and the affected area is the immediate space around the suction point. Clear that area of anything you care about before the day, and expect a fine layer of dust nearby regardless of precautions.
Can installation happen in winter?
Yes — installations run year round in cold climates. Frozen ground affects exterior trenching, which most residential designs do not need, and roof or ladder work can be delayed by ice or snow. Interior work is unaffected. If your design needs exterior excavation, ask how weather will be handled before scheduling.
Keep reading
- What to expect after installation — Verification, noise, energy, maintenance, and retest intervals.
- Understanding installation quality — What to inspect before the crew leaves, in plain language.
- What makes a great system — Six design choices that decide whether a system performs for a decade.
- How long systems last — The pipe is effectively permanent. The fan is the wear item.
- All homeowner guides — every decision page in one place.
One day, one core hole, some pipe, a fan, and a measurement to follow. The parts of the day worth your attention are the first thirty minutes and the last thirty — the routing decisions at the start and the walkthrough at the end.
Sources
- U.S. EPA — Radon
- U.S. EPA — A Citizen’s Guide to Radon
- U.S. EPA — Consumer’s Guide to Radon Reduction
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