Highest-frequency entry points
- Cracks in concrete slabs and floor–wall cold joints
- Open or poorly sealed sump pits
- Floor drains tied into gravel beds
- Pipe penetrations (water, sewer, gas, electrical)
- Hollow block walls and unsealed top courses
- Crawl-space soil and torn vapor barriers
- Crawl-to-basement doorways and chases
What sealing can and cannot do
Sealing visible gaps is good craftsmanship and helps mitigation systems. Sealing alone seldom replaces active depressurization when indoor levels are well above 4 pCi/L—soil gas finds microscopic paths.
Diagnosis vs guesswork
Visual inspections guide system design. Air testing confirms whether the house needs work. Start with testing fundamentals.
Need a local next step? Call (605) 600-6282 to talk through testing, real estate timing, or mitigation for your Rapid City–area home.