Radon Mitigation System Installation in Peoria, IL

Sub-Slab Depressurization: The Standard Fix

For the large majority of basement and slab-on-grade homes, the fix is a method called sub-slab depressurization, and it is the method the EPA identifies as the most common and generally most effective approach available. A suction pipe is inserted through the foundation slab, down into the layer of aggregate or soil beneath it. That pipe connects to PVC piping routed up through the house, often through a closet or utility space, or in some cases run along the exterior wall, and it discharges above the roofline where the exhausted gas disperses harmlessly into outside air. An inline radon fan, mounted in the attic, garage, or on an exterior wall, provides continuous suction that keeps the soil gas moving out instead of in.

A small device called a U-tube manometer gets installed near the vent pipe, usually in a visible spot in the basement or garage. It is a simple, mechanical way to confirm at a glance that the fan is running and the system is under active suction, no batteries or electronics required. If you ever walk past it and the fluid looks level instead of offset, that is your sign the fan needs attention.

The exact number of suction points a house needs depends on how the slab is built. Homes with a single open area under a continuous slab often need only one suction point. Homes with multiple separate foundation sections, block walls with hollow cores, or additions poured at different times sometimes need two or more points tied into the same system to pull air evenly from beneath the entire footprint.

• •Suction pipe through the slab into the soil below
• •PVC routing to discharge above the roofline
• •Inline radon fan for continuous suction
• •U-tube manometer for at-a-glance system verification

Designing the System for Your Specific House

No two houses get an identical system, because no two foundations are built exactly the same way. Before any pipe goes in, we look at the slab layout, whether there is a basement, crawlspace, or both under the same roof, where the sump pit sits if there is one, and where the pipe can run without cutting through living space or creating an eyesore on the front of the house. A lot of design work is about routing: getting the vent pipe from the suction point to above the roofline in a way that is effective and does not look like an afterthought bolted onto the side of your house.

Homes with a combination foundation, part basement and part crawlspace, for example, often need a system that ties both sections together, since radon does not respect the line between one part of a foundation and another. We will walk through the layout with you before anything is installed, including where the fan will be mounted and roughly how loud it will or will not be, since a properly installed inline fan is quiet enough that most homeowners forget it is running within a week.

Installation Day: What Actually Happens

Most single-family sub-slab systems are designed and installed in a single day. The crew cuts a suction point through the slab, typically a hole a few inches across, digs out a small pit in the aggregate below to create an open cavity for the pipe to draw from, and seals the opening around the pipe airtight. From there, PVC pipe gets run up through the house to the attic and out through the roof, or along an exterior wall route where that makes more sense for the layout. The fan gets mounted, wired to a dedicated outlet, and the manometer gets installed where you can see it.

Homes needing multiple suction points, or homes with a crawlspace involved as well as a basement, sometimes stretch into a second day. Sealing is part of the job too: any other obvious radon entry points, cracks in the slab, gaps around pipe penetrations, an open sump pit, get sealed as part of the same visit so the system is not fighting unnecessary air leaks. When we finish, the system is turned on, the manometer is checked, and you are shown exactly what to look for if something ever needs attention down the road.

Confirming It Worked, and What a System Costs

A mitigation system is not considered finished until a retest confirms it actually did the job. The EPA recommends retesting between twenty four hours and thirty days after a system starts running, and a properly designed sub-slab system will typically bring levels well under the 4.0 pCi/L action level, often down into the range of a home that never had a radon problem at all. After that, retesting every two years is the standard recommendation, since radon levels can shift over time with soil conditions, foundation settling, or renovations that change how the house is sealed.

For a typical single-family home, a sub-slab depressurization system generally runs somewhere in the range of $900 to $2,500, depending on the size and complexity of the foundation, how many suction points the layout requires, and how far the pipe has to be routed to reach above the roofline. Crawlspace involvement and multi-point systems tend to land toward the higher end of that range. That is a typical range, not a quote, since every accurate price follows an actual look at your foundation, not a guess made over the phone.

Frequently Asked Questions