Radon Mitigation Systems Questions


While addressing Radon Mitigation Systems, we have included a few common questions, along with a brief overview of the EPAs very informative Consumer’s Guide To Radon Reduction How to fix your home.   The link for the EPAs Consumer Guide is also included for you, for more of an in-depth read. EPA Consumer’s Guide To Radon Reduction How to fix your home.

I have high radon, can’t I take care of the problem myself?

The EPA recommends hiring a qualified radon mitigation contractor to lower the radon levels. Lowering radon levels requires specific technical knowledge and special skills. Without the proper equipment and technical knowledge, you could actually increase your radon levels or create other potential hazards and additional costs. If you still would like to complete the work yourself, contact Oregon Public Health for training.  Oregon Public Heath Radon Training Information

How can I find a contractor?

The EPA recommends using a certified radon mitigation contractor trained to fix radon issues. To find a licensed mitigation company in Oregon, click on the Oregon Public Health to find a list of licensed contractors. Oregon Public Heath Mitigation Licensed Contractors

What is a good way to determine a good contractor?

Do your homework and get multiple estimates and references. The EPA has an Evaluating and Comparing Contractors checklist that you can follow to evaluate and compare contractors.

Once you have compared and contrasted each proposal, the EPA suggests that you take into account what you will be getting for your money; a less expensive system may cost more to operate and maintain; a less expensive system may have less aesthetic appeal; a more expensive system may be best for your home; and, the quality of the building material will affect how long the system lasts.

The EPA also suggests that homeowners review each of the Contractors Proposals and Estimates.

Once you have decided on a contractor, the EPA suggests checking the Contractors Contract Language before any work starts.  The contract should match the original proposal, describe the exact work that will be completed prior and during the installation of the system, what the system consists of and how the system may operate. Many contractors provide a guarantee that the system will reach a negotiated radon level of 4.0 pCi/L or less.

What are the types of radon reduction techniques?

Contractors will analyze the following factors in selecting a radon mitigation systems for your home; how high the initial radon level is, the cost of installation and system operation, home size, and foundation type.

If your home has a basement or is Slab-on-Grade (concrete poured at ground level): In these homes, radon is usually reduced by Active Soil Depressurization System (ASD), this is the most common and usually the most reliable radon reduction method. This system creates a vacuum under the house to intercept radon before it enters the home. This is accomplished by inserting a suction pipe through the floor slab and into the soil underneath. A vent fan is connected to the suction pipe and draws the radon gas from below the home, the gas is then drawn up and dispersed to a discharge pipe and then vented above the home and into the outside air.

Radon Mitigation Systems

Radon Mitigation Systems – Interior Sub-Slab System

Radon Mitigation Systems

Radon Mitigation Systems – Two interior Sub-Slab systems.


Radon Mitigation Systems

Radon Mitigation Systems – Exterior Sub-Slab System

Radon Mitigation Systems

Radon Mitigation Systems – Installed Exterior Sub-Slab Mitigation System. The radon is vented above the roof line and the system has been designed to incorporate aesthetic features that correspond with the house.

If your home has a crawlspace: In these homes, the most effective method to reduce radon levels is through a sub-membrane suction. The sub-membrane involves covering the crawlspace floor (usually dirt) with a high-density plastic sheet. A vent pipe and fan are used to draw the radon from under the sheet and vent it to the outdoors.

Radon Mitigation Systems

Radon Mitigation Systems – Sub-Membrane System

Photos below show the installation of a Sub-Membrane Radon Mitigation System 

Radon Mitigation Systems

Radon Mitigation Systems – Technician coring hole for the piping to feed through the crawlspace to the exterior of the home.

Radon Mitigation Systems

Radon Mitigation Systems – Interior shot from the crawlspace, where the hole for the radon piping will fee through. The black sheeting is a pre-existing vapor barrier.

Radon Mitigation Systems

Radon Mitigation Systems – High density sheeting covering the crawlspace floor.

Radon Mitigation Systems

Radon Mitigation Systems – Interior view of the crawlspace, vent pipe and fan are used to draw the radon from underneath the high density sheeting and vent the radon gas to the outside.

Radon Mitigation Systems

Radon Mitigation Systems – Sub membrane sheeting with 4 inch pipe going to exterior of home.


Additional approaches to radon reduction: Besides the installation of a mitigation system, sealing cracks and other openings in the foundation will limit the flow of radon into your home. The EPA does not recommend the use of sealing along, as sealing by itself, has not been shown to lower radon levels significantly or consistently.

Checking the Contractors Work

The EPA recommends that you Check the Contractors Work with a list of basic installation requirements that should be met for the radon reduction system in your home.

Maintaining and Living with a Radon Mitigation System

Occasional maintenance may be required with the radon mitigation system. If you have a fan powered system, you will need to monitor the warning device, to make sure the system is working correctly. Fans may last for five years or more, and then may need to be repaired or replaced. On average, manufacturer warranties for the fans do not exceed five years, so the cost to replace the fan varies based on labor and materials. It is also recommended that the home is retested every two years to ensure that the system is working properly and the radon levels remain low. The fan must run continuously for the system to work correctly, do not shut it off.