Radon Mitigation System Installation in Winona
A properly installed sub-slab depressurization system pulls radon out from under your foundation and vents it above the roof, where it disperses safely. Most Winona homes finish under 2.0 pCi/L. Most installs take one day.
How sub-slab depressurization works
Radon enters your house because the soil under the slab sits at higher pressure than the air in your basement. A mitigation system flips that balance. A licensed installer cores a hole through the basement floor and opens a small suction pit beneath it. A PVC pipe runs from that pit up and out above the roofline. An inline fan keeps a steady, gentle pull on the soil, so radon leaves through the pipe before it reaches your living space.
On most Winona homes the job includes:
- One or more sealed suction points through the slab
- An airtight sump basket lid, because an open sump is a major radon entry point
- Caulked slab cracks and floor-to-wall joints where they matter
- A quiet inline fan sized to your foundation, not a one-size default
- A vent stack that ends above the eave line, per code
- A manometer gauge so you can see at a glance that the system is running
- The MDH system tag Minnesota has required on every install since 2019
Different foundations, different systems
Basements
Basements are common across Winona's older neighborhoods and the newer builds on the bluffs. They are also the most straightforward to mitigate. One suction point handles most homes. A larger slab or an addition sometimes needs two.
Crawl spaces
Crawl spaces get sub-membrane depressurization. A sealed vapor barrier goes over the dirt floor with suction drawn from underneath it. You find this setup in the older farmhouses out through Winona County.
Slab on grade
No basement does not mean no radon. A slab home gets a suction point through the slab or a side-wall route. These jobs vary the most. That is why the pro quotes after a few questions about the house.
Homes built after 2009: the cheap fix
Minnesota's building code has required passive radon-resistant construction in new homes since June 2009. If your house is newer, a capped PVC stack probably already runs from under the slab up to the attic. When a passive home still tests high, adding a fan to that stack is a smaller job than a full install. It usually costs noticeably less. Test first, then activate only if the number calls for it. Not sure which step your house is on? See testing vs. mitigation.
After the install: the follow-up test
Every system gets a follow-up radon test after it has run for at least 24 hours. You see the before number and the after number. Minnesota licensing rules also put the installer's details on the MDH tag attached to the unit, so any future owner, inspector, or agent can verify the work. If you are selling, that tag and the post-test result become part of your disclosure paperwork under Minnesota's Radon Awareness Act.