Radon. How does mitigation work?

This repair fits under the finite repairs you may find after your home inspection. If you find that you have Radon gas above the action level of 4.0 pci/l, there are tried and true cures for that problem.

To mitigate for Radon, a system is installed that creates a slight vacuum under the basement slab.  This keeps the radioactive gas from entering your home and collecting there. The air passes through a PVC pipe, using a fan, and is discharged above the roof line. The system looks like this.

Generally, it takes about half a day to install and the cost is almost always less than $2000 and often less than $1000. (My most recent client paid $975.) Things that make it more costly are installation problems in mitigating rooms with no basement beneath or if the installer has to work around rock ledge immediately under the basement floor.

In older houses two PVC pipes are used, since there is dirt or sand under the basement slab. In new construction, one pipe is enough because there is gravel under the slab and air moves more freely.

Fans come in different sizes and strengths. The technician will determine what you need. Fans are generally come with a 5 year warranty. They generally last about 12 years. Replacement is about $300-400.

Whether the fan and pipe are inside or outside is a matter of taste and preference. The fans last slightly longer if they are installed outside, because attics get very hot and that is hard on the fan mechanism. The difference is not striking.

Some people prefer to install the pipe and fan through the inside of the house, so that it isn’t ugly outside. In interior installations, there needs to be places to run the pipe from the basement to the roof without being ugly in the house. The fan is installed on the pipe in the attic area. If you have closets in a row on the main level and upper levels, this works easily. Otherwise, the pipe will go up in a corner and the technicians will build a box around it.

If you have a place where the white pipe and fan will not be visually bothersome, like behind a chimney on the side of the house, the outdoor option works well.

Once your system is in place, it is tested. The installers will guaranty that the levels will remain below 4.0pci/l as long as the fan is operating. It is obvious with a glace whether the fan is working, just check the gauge on the pipe every month or so. It is recommended that you retest every two years.

So, if your home inspector tells you that the house you want to buy has a Radon problem, don’t panic. It is a relatively easy fix with a finite cost.

Radon. Is it in my house and why should I care?

Radon. Is it in my house and why should I care?

What is Radon and why should you care? According to the EPA

Radon is a naturally-occurring, invisible and odorless radioactive gas. One in 15 American homes contains high levels of radon. Radon gas is not isolated to certain geographical areas or home types. Radon problems have been detected in homes in every county of the U.S. It caused more American fatalities last year than carbon monoxide, fires, and handguns combined! If a home hasn't been tested for radon in the past two years, EPA and the Surgeon General urge you to take action.

As part of your home inspection, most single family house buyers get a radon test. There are two kinds of test devices: passive canister or continuous monitor test. The passive canisters can be bought at hardware stores all over the area or a home inspector can bring them and set them up, for a fee. Some of the hardware store brands have the lab fees included and some don’t, so read the package before buying. With my clients, I prefer these because the lab is in Massachusetts, so we get the results quickly and reliably. The continuous monitor tests are more expensive, because you are renting the machine and using the tech’s time to set up and pick up. The up side is the machine can detect if windows have been opened, so you know that test conditions were done correctly. Also, with the machine, you get the readings almost right away. With canisters it takes a couple of days to get them to the lab for reading.

I spoke to John Lugo at Eagle Environmental about testing. He told me that radon takes only 12 hours to get to its peak reading level. So, an accurate test can be achieved if a house is closed up for 12 hours before testing begins. The radon level does not get higher and higher the longer a house is closed up. So, if you get a high reading on an empty house, it is not a false positive.

To get a true test, make sure the windows are closed. You can get a false positive if the seller opens the windows during the test. You may also get a false negative. The way that the false positive happens is that if the open window increases the upward flow of air in the basement, then more radon will be detected. Canister tests can be fouled that way. The machine tests are sensitive to air pressure changes, so the technician can see if windows or doors were opened enough to invalidate the results.

The EPA action level for Radon is 4.0 pci/l. If your results are below that, you basement has passed the test.