Low Clearance Crawlspace & Basement

Monday, January 5th, 2026 by Brian Notestein

Challenge

Purple Mountain Radon was called by a homeowner who was selling his home which was constructed in the foothills of the Rocky Mountains in the year 1894. His home had a radon mitigation system installed 3 years prior but the radon level was not successfully reduced by the contracted radon mitigator; as measured by the buyer's radon test which was above 8 pCi/L.

Purple Mountain Radon inspected the home and found a low clearance crawlspace adjacent to a cellar/basement where the HVAC equipment and water heater were located. Additionally, behind the HVAC system was a wall that separated the basement into another crawlspace area that was inaccessible. The radon contractor installed a vapor barrier and sealed to the walls where he could. Due to the low clearance, inaccessible crawlspace area, and stone wall foundation, a complete seal was impossible to achieve. He did not attempt to address the basement slab.

To add to the challenging project, the next door empty lot was excavated for a new house build the day after our install. Disturbing the soil in this way greatly increases the amount of radon that is released.

Solution

The crawlspace area was approximately 900 square feet with the basement taking up about 300 square feet. Purple Mountain Radon has had success deploying the RadonWell and recommended to install a RadonWell in the crawlspace. A secondary suction point into the basement slab was also recommended to apply suction at the lowest point of the structure. The previous radon contractor installed a fan that works adequately in a crawlspace situation, but not in applying high amounts of suction force to a sub-soil or sub-slab scenario, and thus, installing a high suction fan, in this case, a Festa Eagle Extreme, was installed.

The presently installed vapor barrier was left intact and not sealed. Post-install testing resulted in bringing down the radon to 2.7 pCi/L

Project Summary

Project Designer & Installer: Brian Notestein

Products Installed:: RadonWell, AMG Festa Eagle Extreme.

The original installed fan was replaced with an AMG Festa Eagle Extreme with the intention to apply a high amount suction against the soil from the RadonWell and Sub-slab.

The original radon contractor faced stone walls and low clearance when installing the vapor barrier. The vapor barrier was unable to be sealed at the perimeter.

The original radon contractor used a piece of drain tile and connected between the perforated pipe beneath the vapor barrier and that of the exhaust point.

Purple Mountain Radon installed a RadonWell (where the pipe goes vertically below the soil) and connected it to the sub-slab suction point (to the right of the valve).

About the author

Brian Notestein

Owner

With an estimated 21,000 annual deaths attributed to radon induced lung cancer, we are working toward saving lives with every mitigation system we install. Let's reduce that number each year.

Back to Previous Page Back to Case Studies

Low Clearance Crawlspace & Basement

Challenge

Solution

Project Summary

About the author

We serve the following areas