Crawl Space Radon Mitigation in Lincoln, NE

Why crawl spaces need a different system

A standard mitigation system pulls soil gas from beneath a concrete slab — the slab itself acts as the lid. A crawl space has no lid: the soil is exposed, and radon rises straight off it into the air under your floor, then up into the house through gaps, ducts, and the floor itself. There's nothing to depressurize until a barrier is created. That barrier is a heavy-gauge membrane sealed across the entire crawl space floor and up the foundation walls, with the suction pipe drawing from underneath it. The technique is called sub-membrane depressurization, and once the membrane is sealed, the fan does the same job it does under a slab.

Where these homes show up around Lincoln

Crawl spaces are most common in older Lincoln housing stock — pre-war homes near downtown, the Near South, and University Place — and in additions, where a room was built out over a crawl space next to an original basement. Acreages and farmhouses outside town in Lancaster County frequently sit partly or fully over crawl spaces as well. If your home mixes foundation types, that matters: a basement-plus-crawl-space house often needs a sub-slab suction point and a membrane system working together, because treating only one section leaves the other feeding radon into the house.

What the work involves

The crawl space is cleared and the soil surface prepared, the membrane is laid, overlapped, and sealed at every seam and penetration — piers, plumbing, foundation walls — and a suction point is fitted under the membrane and connected to the pipe-and-fan run, which exhausts above the roofline like any other system. A manometer shows the system pulling. Access is the honest variable here: a crawl space with 30 inches of clearance and a dry floor is a very different job than an 18-inch space with debris, old vapor plastic, and ductwork to work around. That's why crawl space quotes usually benefit from a look at the space, or at minimum a good description of it.

What affects cost and scope

Square footage of the crawl space, clearance height, how much prep the soil surface needs, the number of piers and penetrations to seal around, whether a combination foundation needs a second suction point, and the pipe routing to the exhaust point. A well-sealed membrane also brings a side benefit many homeowners notice: less musty crawl space odor and moisture migrating up into the house. See the cost factors page for the full picture.

What happens after you call or request a quote

Describe the house: the test number, which parts sit over crawl space versus basement or slab, and roughly what the crawl space is like inside if you know. Nobody expects you to crawl in there and measure — a plain-language description is enough to start, and the details get confirmed before work is scheduled. After installation, a retest verifies the whole-house level dropped below the action line.

Sealed sub-membrane radon mitigation system in a crawl space

Crawl space questions

My house has a basement AND a crawl space. Which system do I need?

Often both techniques on one fan: a suction point under the basement slab and a sealed membrane over the crawl space, tied into the same exhaust run where the layout allows. Treating only the basement side frequently leaves the level high because the crawl space keeps feeding radon in.

I already have plastic sheeting down in my crawl space. Doesn't that count?

Loose vapor barrier plastic slows moisture but doesn't stop radon — gas moves through the unsealed seams and edges easily. A mitigation membrane is heavier material, sealed at every seam, penetration, and wall, with active suction underneath. The existing plastic usually gets removed or incorporated during prep.

Is a crawl space system more expensive than a regular one?

Often somewhat, because membrane sealing is labor-intensive and access is tighter — but it depends heavily on the size and condition of the space. A small, clean crawl space next to a basement can be a modest addition to a standard system. This is exactly what the quote conversation sorts out.

Will it help with the musty smell downstairs?

Frequently, yes. The sealed membrane and constant suction reduce the soil moisture and odors that migrate up from an open crawl space. It's a side effect, not the goal, but homeowners notice it.