Short answer
Soil suction is EPA's name for the radon systems that draw radon from below a home and vent it outdoors through pipes. In a home with a basement or a slab-on-grade foundation there are four types: subslab suction, drain-tile suction, sump-hole suction and block-wall suction.
What soil suction means
The types differ in where the pipe takes its air. Some homes have drain tiles or perforated pipe to direct water away from the foundation, and suction on them is drain-tile suction. EPA calls sump-hole suction a variation of subslab and drain-tile suction, and says block-wall suction can be used in basement homes with hollow block foundation walls.
A crawlspace gets a fifth form, which EPA calls submembrane suction.
The four types on EPA's figures, from 12 pCi/L
EPA gives each type a typical reduction and a note. The last column applies both ends of the range to a home that tests at 12
| Type | EPA's typical reduction | EPA's note | 12 pCi/L becomes, pCi/L |
|---|---|---|---|
| Subslab suction | 50 to 99 percent | Works best if air can move easily in material under slab | 6 to 0.12 |
| Drain-tile suction | 50 to 99 percent | Can work with either partial or complete drain tile loops | 6 to 0.12 |
| Sump-hole suction | 50 to 99 percent | Works best if air moves easily to sump from under the slab | 6 to 0.12 |
| Block-wall suction | 50 to 99 percent | Only in homes with hollow block walls; requires sealing of major openings | 6 to 0.12 |
What it means for your home
Which type fits depends on what is under and around the foundation: a drain tile loop, a sump, hollow block walls or a plain slab. That is the contractor's call on site.
Whatever the type, the proof is the same: a
Where to go next
- Radon mitigation cost estimator. Price a system by foundation type and state.
- Radon remediation systems: what gets rid of radon. How reduction works and what each approach costs.