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Radon is a known problem in many parts of the country, including the Inland Northwest. The Washington State Department of Health reported that Spokane County has the highest levels of cancer-causing radon gas in the state. The Spokane County Health District has reported that approximately 63% of the houses tested had radon levels above 4.0 pCi/L (picocuries of radon per litter of air). The Idaho Department of Health and Welfare has reported that approximately 60% of the houses tested in Kootenai County had radon levels above 4.0 pCi/L.

Since 1993, all new residential structures in Spokane County require some type of radon mitigation system to be installed due to the known radon problem in the Inland Northwest. When the radon mitigation system is installed during the construction phase, new construction procedures are used which allow the system to be hidden in the walls of the home and a smaller, quieter fan is used. The diagram below shows how a radon system is typically installed in a new home. (Click on photo to open an enlargement)

Diagram of new construction radon mitigation unit

When a radon mitigation system is installed in an existing home, different procedures. In residential retrofits, the radon mitigation system is routed through the interior of the house whenever possible. In some cases, it is necessary to route the system through the garage or on the exterior of the house. The following are examples of some typical radon systems.


   Residential Retrofit Basement Sub-Slab

A typical radon venting pipe from a subslab environment. Attached to the riser is the manometer indicating that the fan is running. The riser is also labeled with the company logo sticker and it is labeled with a warning sticker indicating that this is a radon system.

The riser is supported by a metal strap as it rises vertically and again, against the ceiling as the pipe runs along that part of the structure.

Residential Retrofit Basement Sub-Slab

   Crawlspace
Crawlspace Unit

In homes with a crawlspace, a layer of plastic is laid over the top of the perforated pipe resulting in the radon being draw into the system.

   Radon Pipe Installed in the Closet

Radon systems may also be run through the garage if necessary.

Radon Pipe Installed in the Closet

   Fire Collars in the Garage
Fire Collar in the Garage

Protection from fire is of the utmost importance. When the radon system must penetrate a fire rated wall like the wall into the garage or a fire rated ceiling, a fire collar is used to keep the fire rating.

   Radon Fan Loacted in the Attic

This photo depicts the typical installed radon fan in a resiential attic space.

Radon Pipe Installed in the Closet

   View of Radon Vent Pipe Going Through Different Roofing Materials
Radon Vent Penetrating a Cedar Shake Roof

Cedar Shake
Composite Shingle Radon Vent Penetrating a Cedar Shingle Roof

Masonry Slate Roof

Masonry Slate
   Exterior Systems

When there is no viable internal route for the radon system, an external system is required. We try to conceal the radon system as best we can. We incorporate the system with other mechanical/electrical systems, or place it behind shrubs.

Exterior System


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