Crawl Space Radon Mitigation, Sioux Falls SD

Call (605) 210-7667 You hear back from a person, not an autoresponder, within one business day. Call before 3pm on a weekday and it is usually the same afternoon.

Sealed vapor barrier installed over crawl space soil for radon mitigation in Sioux Falls

Bare soil under a house is an open door. There is no slab in the way, no concrete to crack through, just dirt breathing directly into the space under your floor joists, and the stack effect pulls it upward all winter. Crawl spaces are the single most common reason a Sioux Falls house tests high despite having a perfectly good basement everywhere else.

Sub-membrane depressurization, in plain terms

We lay reinforced polyethylene across the entire soil floor, seal the seams, run it up the foundation walls and mechanically fasten it, and seal around every pier and penetration. Then a suction point goes underneath that membrane and ties into the same fan and stack as the rest of the system. The membrane becomes the barrier and the fan keeps the space beneath it at negative pressure, so gas that used to drift up now gets pulled out and vented above the roof.

Two things you get that have nothing to do with radon

Moisture and heat. Sealed crawl spaces stop pushing ground moisture into the framing, which is why the musty smell in the floor register usually disappears within a few weeks. And the floors above get noticeably less cold in a South Dakota February, because you have taken a vented dirt pit out of the thermal path. Nobody buys a radon system for warmer floors, but it is the part homeowners mention a year later.

Mixed foundations are the norm around here

Plenty of older houses in Sioux Falls, and most of the acreages out toward Hartford and Colton, are part basement and part crawl. That combination gets one fan and two suction points, one under the slab and one under the membrane, joined into a single stack. Treating only the basement half is a mistake we get called in to correct fairly often, and the giveaway is a system that runs perfectly and still tests at 6.

Does the whole crawl space have to be covered?

Yes. Partial coverage leaves the exposed soil doing exactly what it was doing before. The membrane runs wall to wall, up the foundation walls, and is sealed around piers and pipe penetrations.

Can I still store things in the crawl space afterward?

Yes, though carefully. The membrane is durable but it is not a floor. Anything with sharp corners should sit on a scrap of plywood so it does not puncture the seal you just paid for.

What if my crawl space has standing water?

That gets solved first. Drainage and grading come before a membrane, because sealing over standing water traps a moisture problem instead of fixing it. We will tell you honestly if the crawl space needs drainage work we are not the right company to do.

Available across the Sioux Falls area

Also serving Brookings, Mitchell, Watertown for this service. Call and ask when we are next in your direction.

Related radon services

Need crawl space radon mitigation in Sioux Falls? Call (605) 210-7667 or send the form for a written, itemized quote. Back to radon mitigation in Sioux Falls.