Crawl Space Systems in Dell Rapids, SD

Call (605) 210-7667 Dell Rapids is 22 miles from Sioux Falls. 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.

A crawl space cut into or onto quartzite is a different job from one over soil. Around Dell Rapids you occasionally find crawl areas where the floor is partly exposed rock, and a membrane cannot be sealed to rubble the way it seals to a poured wall or level soil.

What we see in Dell Rapids

Through the older grid off Fourth Street, crawl areas under rear additions frequently sit directly on or near the bedrock that made this town a quarry site in 1875. Those need mechanical fastening, a batten strip, and considerably more sealant than a standard job.

Practical notes for Dell Rapids homeowners

This is a case where the estimate should include a look inside the crawl space rather than a measurement from the hatch. If a contractor prices a Dell Rapids crawl without going in, the number is a guess.

Crawl Space Systems in Dell Rapids: the technical part

Crawl areas here sometimes sit partly on exposed quartzite rather than soil, which changes the sealing detail entirely. A membrane seals well to smooth poured concrete and to level soil, and poorly to irregular rock. Getting a durable seal on a rock floor means more mechanical fastening, more sealant, and a realistic conversation about which sections of perimeter will hold and which will not.

What the job looks like in Dell Rapids

Expect an inspection from inside the crawl at the estimate stage rather than a look through the hatch, because the floor material and the perimeter condition are the two things that set the price and neither is visible from the opening. Where rock is exposed, we fasten to a batten and bed the membrane edge in sealant rather than relying on tape.

The ground under Dell Rapids

Commercial quarrying of Sioux Quartzite started here in 1875, and the reason is that the bedrock is at or near the surface where the Big Sioux cuts through the Dells. Very little glacial cover, heavily fractured Precambrian rock, and joints that carry soil gas straight up. If you want to understand why eastern South Dakota is in EPA Radon Zone 1, stand at the Dells and look at the rock face.

Dell Rapids radon questions

Can a membrane seal to bare rock?

Reasonably well with the right detailing, and never perfectly. The system is sized to account for what cannot be sealed, which is why the diagnostic reading matters more here.

Is the exposed rock making the radon worse?

The fractures in it are the pathway, so effectively yes. Bedrock at the surface with open joints is why this town reads the way it does.

Need crawl space radon mitigation in Dell Rapids? Call (605) 210-7667 or send the form. Full detail on how these systems work is on our crawl space radon mitigation page, and every radon service we offer in Dell Rapids is listed on the Dell Rapids page.