Poured concrete basements are common in York County homes built over the last several decades. They are often the most straightforward foundations for radon mitigation. This guide walks through a typical sub-slab install from start to finish, so you know what to expect on the day of the work. The answers below come up in almost every visit.
What happens during a sub-slab radon install in a poured basement?
During a sub-slab install in a poured basement, the contractor runs a quick suction test to pick the suction point, drills a core hole in the slab, removes some soil or gravel underneath, and seals a pipe into the hole. The pipe runs to a fan outside the living space and vents above the roof. Cracks and openings are sealed, a U tube gauge is added, and a retest is scheduled after the system runs.
Choosing the Suction Point
The install begins with a decision about where to place the suction point. The contractor drills one or more small test holes and uses a vacuum and a pressure gauge to see how well air moves under the slab.
Poured basements often have a gravel layer under the concrete, which helps suction spread. A single suction point near the middle of the slab or near the planned pipe route can often cover the whole floor.
Location also depends on practical things: where the pipe can rise or exit, where the fan will go, and whether the area is finished. The contractor balances suction and convenience to pick a spot. A short visit usually answers most of these questions for your particular house.
The Core Hole and Pipe
At the chosen spot, the contractor drills a core hole, usually several inches across, through the slab. Some soil or gravel is removed from beneath the hole to create a small open pit. This pit helps the fan pull air from a wider area.
The pipe is set into the hole and sealed to the concrete. From there it runs to the fan location, either up through the house to the attic or out through the rim joist to an exterior wall.
Cracks in the slab, the joint where the floor meets the walls, floor drains, and the sump are sealed as needed. These steps keep basement air from being drawn into the system and keep more soil gas out of the house.
Fan, Gauge, and Startup
The fan is mounted outside the living space, in the attic or on the outside of the home. It is connected to the pipe with rubber couplings and wired to power. The exhaust pipe continues above the roofline.
A U tube gauge is installed on the pipe in the basement. When the fan starts, the liquid shifts, showing suction. The contractor often marks the starting level so you can spot changes later.
Before leaving, the contractor should show you the gauge, explain what the fan should sound like, and give you the paperwork for the job. Plan a short-term retest after the system has run at least a full day. A few minutes spent on this step often prevents a return trip or a second round of adjustments.
A Straightforward Install
In a poured concrete basement, a sub-slab install is often completed in a single day. Knowing the steps helps you prepare and ask good questions. Having the plan in writing makes the decision easier and the follow-up simpler. Call us and we will connect you with a local contractor who can assess your York basement and walk you through the plan.
Frequently Asked Questions
How long does a sub-slab install take in a poured basement?
Many poured basement installs are finished in one day. A complicated pipe route, finished rooms, or additional suction points can add time. The contractor gives you an expected schedule with the estimate. Ask about it during the visit so the answer is based on your actual home.
Will drilling the slab make a mess?
Drilling concrete creates dust, but contractors control it with a vacuum at the drill and sheeting around the area. Ask how dust will be managed and how the area will be cleaned when the job is done. Ask about it during the visit so the answer is based on your actual home.
Do poured basements always need sealing work too?
Most do to some extent. Sealing the sump, floor drains, and larger cracks helps the system work more efficiently. The contractor notes what needs sealing during the estimate and lists it in the written scope. The answer can change from one house to the next, so an on-site look helps.