Radon and water: fix them before the walls go up

Radon Zone 1

The state's Department of Agriculture and Natural Resources places eastern South Dakota, Sioux Falls included, in EPA Radon Zone 1. That's the zone where average indoor levels are predicted to run above the EPA's action level of 4 pCi/L.

We recommend a radon test before finishing. The state says to test in the lowest livable level of the house.

Mitigation before framing

If the result is high, a mitigation system is easier to route before the walls go up. We ask the radon question before framing and leave room for a mitigation pipe if you need one.

South Dakota's Department of Agriculture and Natural Resources lists an average of about $1,200 to install a mitigation system. Treat that as an estimate, not a quote.

Where the sump water goes

In Sioux Falls, city rules bar sump pump water from the sanitary sewer, so we check where yours drains before we build around it. The City of Sioux Falls notes that heavy rain can raise groundwater enough to keep a sump pump running almost nonstop.

National guides put sump pump installation at about $600 to $1,600. Water problems that need a sump pump, drainage, or waterproofing first push a price up, and a dry basement with sound walls and floor brings it down. These are estimates, not quotes, and the basement cost guide lists both.

Waterproofing before drywall

A basement that gets damp sometimes can often still be finished, but fix the water first. Drywall and carpet over a moisture problem trap it in the walls. At the quote we look at the walls, the floor, the sump pit, and the drainage, and any waterproofing comes before framing.

Older basements get the same check. Dell Rapids has more older houses than the newer suburbs around Sioux Falls, and an older basement gets a close look at the walls, the floor, and water before we plan any framing. If opening up old walls turns up water damage or mold, we stop, show you, and price the fix in writing before we go on. See basement remodeling.

Then the finish

Once the basement is dry and the radon plan is set, the finish goes in stages: framing, insulation, and rough-in, the inspection before drywall, then the close-up and the final inspection. See full basement finishing for what's included.