Include a radon test in your home inspection
Radon was an afterthought in my home buying process. My buyer's agent never insisted I add a radon test to my home inspection but upon reading into radon and how the EPA states it is the second-leading cause of lung cancer in the US, I decided the $125 add-on test would offer me peace of mind. My inspector, Brian of Premier Inspection & Consulting LLC, ran a 48-hour test in the basement and sent me the results: an average of 11.1 pCi/l with a peak of 22.3 pCi/l. The EPA recommends installing a radon mitigation system with any result over 4.0.
Both my buyer's agent and inspector downplayed the significance of these numbers as any real health hazard, but I used it as leverage in the home inspection contingency of my offer to purchase. I was quoted an average of $850 to install a radon mitigation system by three estimates in the Madison area, so I requested this amount in addition to more funds to cover the other post-inspection repairs. The seller obliged to cover the full cost. With these funds paid by the seller, I accepted Janesville-based A.T. Pro Mitigation Systems' bid to install the radon mitigation system instead of tackling it as a DIY project.
Radon mitigation basics
If you are unfamiliar with radon gas and how to mitigate that in your home, the EPA does provide an outstanding Consumer's Guide to Radon Reduction.A few things I learned about radon mitigation (or reduction) systems - they are very fast to install (usually 3 hours), there are lots of methods available, and mitigation is not limited to installing the system itself. My home inspector recommended the more common active (subslab depressurization) method, which makes use of a radon fan that draws the gas from below the foundation and directs it towards the outside of the home, above the roof line. Per the EPA, this method reduces radon anywhere between 50 to 99 percent. The EPA provides a table summarizing how each of the methods work in the Consumer's Guide linked above.
Researching the right solution for me
My goals in this radon mitigation solution were:- To achieve an average pCi/l level lower than 1.0 (well below the EPA standard of 4.0)
- To be hidden from view as much as possible
- To utilize multiple "above and beyond" methods to maximize reduction
First off, let me say there are some really unsightly radon mitigation systems installed out there. I absolutely do not want 20 feet of PVC pipe sticking out of my siding, as shown here and here. Fortunately, John from A.T. Pro was already on the same page, and he suggested having the piping run through the basement through the garage up to the attic space and out the rear corner of the garage roof so it had minimal visibility from the exterior. This excellent DIY blogger posted photos similar to what I had in mind (shown below):
Installing this way allows the radon fan to operate within the attic space protected from the elements of nature. I figured exposing the fan to rain, snow and melting ice would only shorten the fan's lifespan and require earlier replacement. Also, I don't see many PVC solutions that have the wire guard and cap, so that's a nice touch. I don't want any bugs or rodents finding their way into the piping.
UPDATE (12/26/2012): After doing more research and getting a professional opinion, I decided against the wire guard and cap, opting to leave the top of the PVC exhaust fully exposed. The main reason is to avoid creating a hot/cold air barrier that can create condensation and thus potential mold build-up and restricted air flow. Since the radon fan is designed to pump out more than 40 cubic feet of air per minute, bugs and rainfall won't be a problem. This Ohio-based contractor has a great FAQ page elaborating on this more.
As part of my mitigation system I requested having two entry points into the concrete slab (drilling a hole in one corner and using the sump pump chamber as the other). My thought here is that this would increase the radon suction in case there were multiple sources below. To wrap things up, I asked for complete caulking of the basement perimeter and all visible cracks. Here's a great example on Youtube.
UPDATE (12/26/2012): A.T. Pro talked me out of multiple entry points in the concrete slab, pointing out that it creates conflicting air flow passages where the radon suction is inhibited since the gas has more than one direction it can move. Since my home has full perimeter drain tile leading to the sump pit, there are no barriers underneath the foundation that require more than one suction point.
One extra touch - consider having a condensate bypass kit installed to prolong the lifespan of your radon fan. It's a negligible cost to add-on just in case.
Reviewing the final installation
I cannot over-emphasize getting multiple estimates, researching Angielist for reviews, and selecting a contractor based on a phone or in-person interview after asking a prepared list of questions. Every contractor has a slightly different approach (I prefer one who listens to my needs before telling me how it's done), and these aren't negligible expenses to select the first and only bid you get.A.T. Pro Mitigation listened to my needs and delivered on my goals stated above. I wanted maximum radon suction, so John installed 4" PVC (typically it's 3"), sealed all of the basement cracks and sump crock, and installed a more powerful fan (Radonaway RP265) and made sure a condensate bypass kit was installed. He minimized the use of PVC elbows to ensure the radon suction and exhaust had as little change in direction as possible from the basement suction point straight to the top out of the garage rooftop.
Monitoring post-installation radon levels
There are a variety of one-time charcoal tests used to measure radon levels (such as these from Accustar and First Alert, but I prefer continuous radon monitoring devices that I can use year-round. The most common consumer-grade model I found in my research is the Safety Siren Pro Series3 Radon Gas Detector, but it requires regular re-calibration to maintain its accuracy.
Instead, I bought the Corentium Digital Electronic Radon Gas Monitor, which requires no re-calibration and uses batteries instead of a wall outlet so I can place it anywhere in my basement. I was averaging 0.9 pCi/l with a peak of 2.3 (7-day reading), so I achieved my goal!
Final bill: $845
