Radon Mitigation
Sub-slab depressurization, installed in 4–6 hours, guaranteed under 4 pCi/L.
EPA-protocol active SSD systems for Cedar Rapids homes. One suction point, one quiet inline fan, post-mitigation verification included. Written sub-4 guarantee — if we don’t hit it, we come back and tune the system free.
What we install
An active sub-slab depressurization (SSD) system is the EPA-recommended mitigation method for basement and slab-on-grade homes. Components:
- Suction point: a 4–5″ cored hole through the basement slab with a small excavated pit underneath (~5 gallons of pea gravel)
- PVC riser: 3″ or 4″ Schedule 40 PVC from the suction point up through an unfinished wall, chase, or closet, and out above the roofline
- Inline radon fan: a 25–80 watt continuous-duty fan mounted in the attic or on an exterior wall (per EPA protocol, never inside conditioned living space)
- Manometer: a U-tube pressure gauge tee’d into the riser so you can verify the system is running at a glance
- Sealing: any visible cracks in the slab, the sump pit perimeter, and the rim joist sealed with polyurethane caulk to prevent short-circuiting
- Exterior vent termination: above the roof eave, 10″ above and 10″ horizontal from any window or air intake, per EPA SGM-SF protocol
What the install day looks like
Arrival (1 hour)
Lead tech walks the basement with you, confirms the suction-point location, and reviews the routing plan. We tarp the work area and bring in a HEPA vacuum to manage concrete dust.
Coring & excavation (1–1.5 hours)
Cut the slab with a wet-cored 4–5″ bit. Excavate the pit under the slab by hand and place pea gravel. Seal the slab-to-PVC junction with hydraulic cement.
PVC routing & fan install (2–3 hours)
Run PVC up through the wall cavity or chase, install the fan in the attic or on the exterior wall, terminate the vent above the eave. Mount manometer and label the system.
Sealing & cleanup (30–45 minutes)
Seal any visible slab cracks, sump pit lid, rim joist, and HVAC penetrations. Vacuum the work area. Walk the homeowner through how to read the manometer.
Post-mitigation test (24–48 hours later)
We deploy a CRM on the lowest livable floor and run a 48-hour test under closed-house conditions. Results back the day the test ends. If we’re not under 4 pCi/L, we return free.
How we handle the harder Cedar Rapids housing stock
Block-wall basements (1960s–1980s)
Block walls leak through the hollow cores. A standard slab-only SSD won’t address that — we either depressurize the block wall directly (drilling a few small holes near the top course and sealing the wall) or seal the rim joist comprehensively. Common in Walford, parts of Marion, and older Hiawatha homes.
Walkout and daylight basements
The exposed walkout side complicates pressure dynamics. We route the suction point on the buried side of the slab and seal the walkout side rigorously. Common in Robins and Center Point.
Newer homes with passive rough-in (post-2010)
Most northeast Cedar Rapids and post-2015 Ely builds have a passive radon stack already roughed in — a sealed pipe from the sub-slab up through the roof, but no fan. We activate the existing stack by cutting in an inline fan in the attic. Install time is faster (2–3 hours) and the price is meaningfully lower than a full retrofit because the riser doesn’t need to be cut and routed.
Stone or rubble foundations
A handful of older Ely and Cedar Rapids homes have stone or rubble foundations — no slab. Mitigation here is custom (often a sub-membrane depressurization with a 6 mil poly liner). Quoted case-by-case.
The sub-4 pCi/L guarantee, in writing
Every install contract includes a written guarantee that the post-mitigation test will read below the EPA action level of 4 pCi/L. If the test comes back at 4 or above, we return and tune the system — new fan, additional suction point, more sealing, whatever it takes — at no additional charge until we hit sub-4. We rarely use this clause (less than 5% of installs need a second visit), but it’s on every contract because radon mitigation should come with accountability.
Frequently asked questions
What exactly is sub-slab depressurization and why is it the standard?
Sub-slab depressurization (SSD) works by creating a small zone of negative pressure under your basement slab. We cut one 4–5 inch hole through the slab, excavate a small pit underneath (about 5 gallons of gravel), and install a sealed PVC riser tied to an inline fan. The fan runs continuously, pulling soil gas — including radon — from under the slab and exhausting it above the roofline. Because the suction is greater than the natural pressure differential pulling radon into the house, no radon enters living space. SSD is the EPA’s recommended method for any home with a basement or slab-on-grade because it’s the only approach that addresses radon at its source rather than trying to dilute it after entry.
What actually determines the price of a Cedar Rapids radon mitigation install?
Three main factors: routing difficulty, slab/foundation type, and number of suction points. The cheapest installs are homes where the suction point sits in an unfinished basement corner and the PVC runs straight up through an unfinished wall to an attic-mounted fan. Add a finished basement and the price rises because we need to plan routing through a chase or closet. Block-wall foundations require rim-joist sealing and sometimes a hollow-block depressurization point. Large slabs over 2,000 sq ft sometimes need two suction points. Walkout basements and homes with sub-slab drain tile loops can actually be cheaper because we can tie into the existing loop.
How loud is the radon fan? Will I hear it from the bedroom?
A properly sized inline fan (RadonAway RP145 or similar) runs at about 45–50 dB measured 3 feet from the unit — quieter than a refrigerator. Mounted in an attic or on an exterior wall, you typically don’t hear it from inside the house at all. If the fan is in a finished basement utility room, you’ll hear a soft hum that becomes background noise within a week. We size the fan to the smallest unit that achieves sub-4 pCi/L, which keeps both noise and electrical cost low. An oversized fan is a sign of lazy design — louder, more expensive to run, and not actually more effective.
What’s the operating cost of running the fan continuously?
A typical 25–80 watt radon fan running 24/7 costs about $4–$10 per month at current Iowa electric rates. The fan needs to run continuously — turning it off resets the soil-gas equilibrium and radon levels rebound within 24 hours. Fans last 10–15 years on average. Replacement is straightforward and our installs are sized so that a replacement fan can be swapped without re-cutting any pipe.
Will the system affect my home’s resale or appraised value?
In Iowa, presence of a radon mitigation system is almost always a positive at resale. The state’s high baseline radon levels mean savvy buyers expect to see either a passing radon test or an existing mitigation system. Homes with no mitigation and no recent test create buyer-side uncertainty, which becomes a negotiation point. Homes with a documented mitigation system and a recent post-mitigation test sailing under 4 pCi/L are essentially radon-resolved from a buyer’s perspective. We give you all the paperwork (system schematic, installation date, post-mitigation results) in a folder you can hand to your future agent.
Call Now
(319) 774-8138
Cedar Rapids radon team. We answer Mon–Sat during business hours. Voicemails returned within 24 hours.
Call (319) 774-8138Have ready when you call:
- Your address (we’ll pull the assessor record)
- Year built and basement type, if you know them
- Any recent radon test result
- Closing date, if it’s a real-estate transaction
Or email info@cedarrapidsradonpros.com.