EXPLANATION OF PROPOSED RADON MITIGATION WORK
SEAL FLOOR AND WALL RADON ENTRY ROUTES
Caulk and seal openings in the concrete or wood floor and foundation walls where radon can enter the structure.
SEAL CRAWL SPACE
Install a gas impervious membrane over the entire soil floor and seal it to the foundation walls with a special adhesive.
Install a large plastic lid with a built in Plexiglas inspection window over the sump hole and seal airtight so radon does not escape into the structure.
SUBMEMBRANE DEPRESSURIZATION SYSTEM
Apply suction under the crawl space membrane using a radon fan, venting the exhaust to the outdoors, at least 10 feet above ground and 10 feet from doors and windows.
SUBSLAB DEPRESSURIZATION SYSTEM
Active soil depressurization
Applying a negative pressure under the sub-floor, concrete or wood, using an in line centrifugal radon fan which draws radon an air through a PVC plastic pipe and vents it to the outdoors, exhausting at least 10 feet above ground and 10 feet from doors and windows. This fan runs constantly at 40 to 90 watts and costs approximately $30.00/year in electricity.
SYSTEM FAILURE INDICATOR
A "U" tube micromanometer (a plastic U shaped clear tube with a red non-toxic liquid inside) mounted on the PVC pipe which indicate air flow in the pipe so that you can see if the system is working.
DIAGNOSTIC SMOKE TEST
A test performed to indicate soil permeability to determine how much suction is needed by the system. It involves drilling two or more small holes in the concrete floor, attaching a vacuum to one hole and shooting a chemical smoke in the other(s). If the smoke is pulled down the hole by the vacuum, the permeability is good, therefore a high suction system is not needed, only a low suction system is necessary.