Radon Mitigation

This is the third and final post in a guest series about radon gas in the home by Rick Galarneau, owner of MassRADON. Be sure to read Part 1, Radon Gas and How It Gets Into Your Home, and Part 2, Testing for Radon in Your Home.

Radon mitigation is the process of removing radon gas from the home to a level that is considered safe.

Removing airborne radon usually begins by first sealing entry points for radon. This is accomplished by caulking any cracks and holes in the basement floor and sealing sumps. Crawl spaces with open earth floors should be sealed in a thick plastic sheet. Depending on the initial test results, these steps can often reduce radon levels on their own.

If a mitigation system is still needed after the above steps are completed, then one or two (rarely more) 4″ holes are drilled in the concrete floor. The “plug” of concrete is removed and then some of the underlying material — dirt, sand, gravel, stones, etc. — is removed to create a pit. PVC piping is inserted into the hole and sealed. The pipe is directed to the exterior of the house or into an attached garage, where a radon suction fan is attached. The exhaust side of the fan is also piped, and it’s directed to a point above the roofline of the home. Radon gas must be discharged above the roof so that it can be carried away by the wind.

This is a standard mitigation system and costs typically fall in the $1,100 to $1,500 price range, depending on the extent of work and amount of materials needed. These systems work well in most houses, but not all. Very old homes and homes with dirt floor basements may require other work or a fresh air ventilation system to dilute the radon to a safe level. There are many variables that will determine how well a system will work and what type of system may be needed in a given home. A site visit should be completed before a quote is offered.

Radon in your well water is removed in a different way. This type of mitigation requires a system that strips radon from well water by aeration. A unit is installed that takes well water from your storage tank in the basement and directs it in the radon system. Thousands of air bubbles are introduced into the water, which strips the radon gas molecules and vents them to a point above the roofline. These systems are usually about 98% effective in their reduction capabilities and cost around $4,500. Again, a site visit is required to determine several things, including the size and material of the water main coming from the well tank and a viable route for the vent pipe, and to ensure that the electrical system is capable of accepting an additional circuit.

Allow plenty of time for the radon mitigation process to be completed, especially when you are selling your home. Mitigation is generally a fairly quick process, and most systems can be installed in a few hours, but occasionally repeat visits may be required to install additional suction pits or make other modifications to the system in order to obtain acceptable results. This may require testing in between the visits to determine the effectiveness of the modifications. Allowing plenty of time for the mitigation process will help you reach acceptable reading levels without interfering with your closing date.