System Types
Basement and Slab-on-Grade Houses

In houses that have a basement or slab-on-grade foundation, radon is usually reduced by one of four types of soil suction: subslab suction, drain tile suction, sump hole suction, or block wall suction.

Subslab suction: is the most common and usually the most reliable radon reduction method. Suction pipes are inserted through the floor slab into the crushed rock or soil underneath. They also may be inserted below the concrete slab from outside the house. The number and location of suction pipes that are needed depends on how easily air can move in the crushed rock or soil under the slab, and on the strength of the radon source. Acting like a vacuum cleaner, a fan connected to the pipes draws the radon gas from below the house and then releases it into the outdoor air. Passive subslab suction is the same as active subslab suction except it relies on natural pressure differentials and air currents instead of a fan to draw radon up from below the house. Passive subslab suction is generally not as effective in reducing high radon levels as active subslab suction.

Drain tile suction: Some houses have drain tiles to direct water away from the foundation of the house. Suction on these drain tiles is often effective in reducing radon levels if the drain tiles form a complete loop around the foundation.

Sump hole suction: Often, when a house with a basement has a sump pump to remove unwanted water, the sump can be capped so that it can continue to drain water and serve as the location for a radon suction pipe.

Block wall suction: Block wall suction can be used in basement houses with hollow block foundation walls. This method removes radon from the hollow spaces within the basement's concrete block wall. It is often used together with subslab suction.

NEXT