If our radon test came back above 12, will a mitigation system really get our home to a safe level?

Yes. A high reading like 12 does not mean your house is broken. It means there is a lot of radon gas coming up through the slab, and an active sub-slab mitigation system is built to pull that gas out before it ever reaches your living space. Our radon mitigation runs $900 to $6,000, and most homes land around $1,950 to $2,250.

A number above 12 sounds scary. We get that call a lot. But the size of the reading is not the thing that decides whether a system works. The system works by changing the air pressure under your basement floor. A fan pulls air and gas from beneath the slab and vents it up and out above the roofline. Whether you started at 5 or at 20, the same physics applies. The gas goes out the pipe instead of into your home.

The EPA action level is 4.0 pCi/L. The EPA says to fix any home at or above that, and to consider fixing between 2 and 4 (EPA, epa.gov/radon). So a 12 is well over the line. It needs a system.

How the system actually does it

Most homes here have a poured slab. We core a hole through the floor, set a suction pit under it, and run a sealed PVC pipe up through the house or up the outside wall. An inline fan runs all the time and keeps a low pressure under the slab. Radon follows the path of least resistance, which is now the pipe, not the cracks in your floor or the floor wall joint.

If your home sits on a dirt or fieldstone crawl instead of a slab, the fix is different. There we lay a sealed membrane over the dirt and pull from under it. That is called sub-membrane depressurization, and yes, we install those too.

We seal the obvious openings before we ever turn the fan on. Cracks, the sump pit, the floor wall joint. The tighter the floor, the better the fan can hold its pull. That is why a clean install matters more than a big number on a test.

Will it really get you to a safe level

A well designed active system is the standard fix for high readings, and that is true at 12 just like it is at 6. We design and balance the system for your home, your slab, and your foundation type.

Our radon mitigation carries a 10-year warranty on the system. We do not put a guaranteed final pCi/L number in writing unless we have agreed to that in writing with you, because the final reading depends on a post-mitigation retest, and that retest is your job to run after we are done. You place a fresh test kit, you read the result, and that is your confirmation the system did its work. We will tell you how and when to do it.

What drives the cost

Radon mitigation runs $900 to $6,000, and most homes land around $1,950 to $2,250. A radon test, if you still need one, runs $50, credited toward the job if you move ahead. What moves the number is the run of the pipe, how many suction points your slab needs, whether we go up through the interior or up the outside, and whether you are on a slab or a crawl. A simple slab with one good suction pit is the easy case. A big footprint or a fieldstone crawl takes more.

You do not need to gut your basement or dig up the yard to fix radon. Most of this work happens in a day. If a contractor tells you a 12 means a giant project, get a second look.

If you are also dealing with water down there, the radon fan and a waterproofing setup can share the same slab penetrations, so it is worth handling both at once. See basement waterproofing and crawl space services if that is you.

We are licensed and OSHA certified, with a state radon cert (RMS-113966), and Branden, our “B-Radon,” runs our radon work. He is the one who will size your fan and lay out the pipe. Read more on the radon mitigation page or what we stand behind on the 603 guarantee.

Call us at 603-610-1770 or book your free inspection. We will look at your slab, your reading, and your foundation, and give you a quote within 24 hours.

Related questions

Is a radon level of 12 dangerous? It is well above the EPA action level of 4.0 pCi/L, so the EPA says a home at that level should be fixed (EPA, epa.gov/radon). High readings are exactly what an active mitigation system is designed to handle.

Do I need a new test before you install? If you already have a recent result above the action level, you have what you need to move forward. If your test is old or you are not sure of it, a fresh radon test runs $50, credited toward the job if you move ahead. New Hampshire DHHS publishes guidance on testing in NH homes (NH DHHS radon).

How long does a radon system take to install? For a typical slab, most installs are done in a day. A larger footprint, more suction points, or a fieldstone crawl space can add time. We will tell you what your home needs after we see it.

Does the system run forever? The fan runs continuously to keep the pressure under your slab. It uses very little power. Our radon mitigation system carries a 10-year warranty.