Radon in an Upper Floor Condo

Building materials are almost always the source of radon in upper floor condos.

Experience tells us that the primary source of radon emissions in upper floor construction is the masonry blocks used to construct the exterior or “curtain” walls.

Radon that is emitted from the exterior, “curtain” walls collects in the wall cavities between the drywall and the “curtain” walls.

Air conditioner installation defects cause the air conditioner to “mine” this radon collecting in the wall cavities and to transport it to the air  handler and inject into the conditioned air air stream.

Few air conditioning folks are aware of these installation defects, (including leaky supply side ducts) so they may easily overlook the mechanisms that result in high radon levels. Florida radon mitigation training does not address these defects or their cures,

Florida radon mitigation certification training and testing does not address the complexities of adding fresh air to pressurize a breathing zone nor to add fresh air to dilute radon WITHOUT creating new high humidity and mold problems.

As amazing as it may seem, the highest radon level we have encountered in Florida was in a 23rd floor penthouse of a high rise building on Pelican Bay Boulevard in Naples, Florida. The radon level was 35 picoCuries per liter.  Nearly nine times higher that US EPA Action Level of 4.0 picoCuries per  liter. The defective air conditioner installation was causing the air conditioner to “mine” radon from wall cavities and even from remote building voids on other floors and delivering it into the breathing zone of this top floor penthouse.

Air Conditioner Installation Defects must be found and corrected for the best radon mitigation result to occur. If a radon miotigator does not  know how to identify and to correct them, he just adds even more outdoor, hot, humid air to dilute radon.