If a home’s radon level is 4 picocuries per liter or more, the EPA recommends a radon mitigation system (sometimes called radon remediation) to be installed.
A common method utilized to reduce the radon level is “sub slab depressurization”. In this case, a suction point or points are determined and a pipe is inserted through the concrete slab floor. This pipe is connected to other PVC piping and a fan is positioned on the pipe outside the living area. The fan then draws the radon gas from beneath the home and vents it to the outside. A radon mitigation system can cost between $900-$2500.
Choosing a Mitigation Company
A qualified mitigation company is your best choice for installation of a radon mitigation system.
In many states, these companies or individuals are certified by a state regulatory agency such as the DEP (Department of Environmental Protection). If this is not true in your state, then you should look for a qualified mitigator who is NEHA (National Environmental Health Association) certified. When choosing a radon mitigation company, you should ask for their state or NEHA certification number, if they offer free estimates, and a warranty on the system.
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Typically, the mitigation company will visit the home to determine the best configuration of the system and the size of the fan for the type of foundation the house is built on. An estimate of cost for a system can then be determined. After choosing the contractor, plan on 1-2 days for installation.
As always, beware of the lowest bidder. Check for references, job examples, and the amount of time the contractor has been in business.
Life After Radon Mitigation
It is recommended that a radon mitigation system be tested after installation. A test may be performed after the system has been operational for 24 hours or more. A short-term test is usually used for the initial test. In some cases, the estimate given by the contractor may include the retest by a professional company or radon test kits.
A follow-up test is suggested every year to monitor the system’s continued effectiveness.
Arick Amspacker is a certified radon technician and home inspector. Over the years he has taught continuing education courses for Realtors and many first time home buyers seminars, as well as a Community College course on inspections and radon. His website http://www.homeradontest.com sells various types of inexpensive, easy to use radon testing devices, and http://www.radonreporter.com offers a resource for radon information.
Because there is a lot of risk of having radon gas present in buildings in the US, it has become a cause for concern for many homeowners and others who own buildings in the US, especially as the risks associated with inhaling the gas are many including being the fact that this gas is the second most important cause of lung cancer, after cigarette smoking. The need to select a proper solution with regard to radon mitigation systems is indeed high, especially if your building or home is located in a high risk area.
In fact, in some areas, before purchasing property, it is necessary to have a specific test performed to ensure that the building is free from radon gas. You have a number of choices with regard to choosing proper radon mitigations systems including having venting pipes to the exterior of the building in order to expel the gas from the building and this form of radon mitigation system is known as Passive mitigation system.
However, when even this radon mitigation system proves ineffective, and there is still noticeable gas in the home, then you need to choose another option which is the active radon mitigation system that requires installation of a fan that runs through the building and which will create low pressure under the slabs and thus increases the rate at which Radon gas is evacuated.
In this form of radon mitigation, you may need to place the fan in a place such as an attic, which is especially necessary if the foundation of the building is slab-on-grade type or even crawl-space. In addition, you should remember that it is necessary to ensure that the vent that runs through your building’s roof does not let water from the pipe drip down onto the slab underneath because it would prove to be harmful.
The cost of installing passive radon mitigation systems would be around one hundred and fifty dollars to three hundred dollars, while that of an active system would be about two hundred and fifty dollars to five hundred and fifty dollars more, though costs will ultimately depend on how big or small is the building.
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Radon is the number one cause of lung cancer among non-smokers in the United States. As a Certified Property Inspector and Radon tester, I am seeing that most new home buyers are unaware of the dangers of Radon. As a result of this lack of information, most home buyers as well as current homeowners are not having their homes tested for Radon. In many cases, my clients have also been misinformed by real estate representatives or the media regarding both the prevalence and lung cancer dangers of radon. Radon testing if done by the homeowner, is inexpensive, and takes only 48 hours.
Here are some important facts about Radon that homeowners and renters should know to protect the health of your family. According to the Environmental Protection Agency (EPA), Radon is the number one cause of lung cancer among non-smokers. Overall, radon is the second leading cause of lung cancer in the U.S. Radon is responsible for about 21,000 lung cancer deaths every year. Visit cheec.uiowa.edu/misc/radon.html for more on a study by Dr. William Field on radon-related lung cancer in women.
Radon is a cancer-causing natural radioactive gas that you can’t see, smell or taste. The type of construction, foundation or location does not prevent a Radon problem. Its presence in a home can pose a danger to a familys health. The only way to determine if a home has a Radon problem is to have an EPA standardized test done. This test can be completed by the homeowner or a certified professional.
The U.S. Surgeon General and EPA recommend that all homes be tested for radon. All homes can be fixed if there is a radon problem found. The average cost of a radon fix for a home is about $1,200. Some home improvement stores sell inexpensive test kits for about $35 (which includes an EPA certified lab report). However, Consumer Reports recently found that those test kits were not very accurate. Therefore, if you want to do your own testing contact your state radon office for a better quality inexpensive test kit.
If the homeowner or buyer/seller does not or cannot to do the Radon testing (some states require a professional complete the test during a real estate transaction), visit the National Environmental Health Association Radon Certification website at: radongas.org/radon_measurement_service.shtml This site has properly certified radon testers as myself listed by the cities in your state.
The untimely deaths of Peter Jennings and Dana Reeve have raised public awareness about lung cancer, especially among people who have never smoked. Smoking, radon, and secondhand smoke are the leading causes of lung cancer. Although lung cancer can be treated, the survival rate is one of the lowest for those with cancer. In many cases lung cancer can be prevented; this is especially true for radon.
EPA has designated January as National Radon Action Month, a time when state radon programs and other partners conduct special radon outreach activities and events across the country. The aim of National Radon Action Month is to increase the public’s awareness of radon, promote radon testing and mitigation, and advance the use of radon-resistant new construction practices.
Steve Zivolich, is an ASHI Certified Inspector and owner of Guaranteed Property Inspection and Mold Investigation in Southern California. He is also certified in: Radon, Mold, Energy Efficiency and Asbestos testing and investigations.
Sub-slab depressurization or sub-slab suction is probably the most reliable and effective radon mitigation technique. It involves an insertion of a pipe (usually 4 inches in diameter) through the floor slab into the soil or gravel under the foundation. This can be done either from inside the house, or inserted under the slab from the outside. As a side note, this technique is used for houses with a basement or slab-on-grade foundation. If your house has a crawl space, a different technique is used.
Just to give you a quick idea of what’s involved, you’ll need to create a hole (aka suction point) in your slab (approx 4 inches in diameter), remove as much soil and/or gravel from under the foundation as possible, put in place a pipe running out from this suction point to a suitable location, where a special exhaust fan will generate vacuum pressure that will draw radon out from underneath the slab to the outside, thus preventing the radon gas from entering your home. Right, you may say, and I know, because that’s what I said when I first read about this a few years back. Believe me, if you do this right, and there is no reason why you shouldn’t, you’ll see a remarkable decrease in your radon levels, which will often be accompanied by a fresher indoor air quality as well (this is one positive side effect of installing this system).
Now, there are different ways of going about this, but I am going to go through one example … in my opinion probably the most likely solution for the majority of home owners (remember, this is not for a house with a crawl space)
My best advice for you is to pick the spot most convenient to run the pipe out of the basement and start there with a hole. I do think that a suction point near the footer tends to produce better results because there is often more settling there, but really that is not of the greatest importance. You should definitely determine where the pipe will have to exit the basement before you start drilling holes in your floor. Also make sure you are aware of potential drain and water pipes, and possible electrical conduits or in-floor heating.
I am going to assume that if you plan on doing this yourself, you don’t need me to tell you how to make a hole in your slab. Well anyway, one way is to drill a series of holes and then chisel and hammer out the cement chunk. The hole should be slightly larger than the 4” pipe you’ll be using.
Once you have the hole made, it’s time to dig. This is probably the worst part of the job, and it could be relatively easy or very hard, depending on what lies underneath. For best results try removing as much as possible. You are trying to create a sort of a vacuum chamber under the slab that will draw in radon and moisture from underneath the entire foundation, so this can make or break your mitigation system. No matter what you have underneath the slab, be it sand, gravel, soil, or any combination of these, try to get 20-30 gallons out, and more if possible, specially for tight soils. REMEMBER this will be the difference between a mitigation system that works and one that doesn’t.
When we did our house, I spent hours scraping away buckets of dirt and gravel till my forearms were bruised. I managed to get about 30 gallons out, and let me tell you, it was worth it.
RUNNING THE PIPES
If you have an attached garage, I would recommend going from the basement, into the garage, and then to the attic, as this is the most feasible solution. Your second choice is to go through the floor above, perhaps through a closet or some other point where the pipe is either not visible or will be easily concealed, and then into the attic where your suction fan would be. The third choice is taking the pipe outside of your house. Personally, I think an outside system should be avoided all together unless there aren’t any other options. Even if it takes a little more effort on your part, try and stick to the indoors for your piping and fan system. Colder climates especially will result in a lot of condensation that can reduce the life expectancy of your radon exhaust fan. You can purchase a condensation bypass kit if you mount your fan outside to prevent water and condensation from ruining your motor.
Back to work… Now that you have your suction point ready, you can use a coupler and secure it using a foam backer (but really you can also use whatever you see fit). Once all your pipes are in place and secure you should caulk this joint for an airtight seal. For the piping, you can use any type of good PVC piping that will fit into whatever you’re using, and make sure that you measure well before you glue your PVC to your elbows and joints. In our home we used a 4 inch sewer pipe and glueless joints/elbows (they have a double rubber seal on the inside to form a water and air proof seal, and the advantage is that you can separate the pipes if you mess up. The only downside is that they are a few bucks more, and really hard to put on, or take off for that matter).
Contrary to what you might be thinking, you cannot just use any ordinary fan for this job. If you are going to invest your time and energy into this, you have to do things right, and you’ll need a special fan that is capable of creating vacuum pressure under the slab without the fan burning out, that can withstand the elements, cold, and moisture, and that will do the job quietly and efficiently.
For your safety, you exhaust Fan has to be located outside of your home’s living space. This leaves you with an option to put your fan in the garage, the attic, or outside. Furthermore, the pipe leading from your fan to the outside must terminate above the plane of the roof, and must be no closer than 10 feet horizontally from windows that open. This is to minimize the possibility of radon re-entering your home.
The size and price of your fan will vary and depends on the square footage of your foundation. The type of soil also plays a role in the fan decision, as you might need a more powerful fan for tighter soils.
As an example if your foundation is anywhere up to 1200 Square feet and your sub-soil is a gravel mixture, an RP145 by RadonAway should be quite sufficient. Most retailers will have a chart or table of different fans, ranging from 3” to 8” duct systems, the latter being used for large projects, such as a school.
Finally no matter where you end up placing your fan, you will need to bring it power. For this, you might need to call an electrician, or not, depending on whether you have a plug-in nearby. Luckily, my father is an electrician, and so we have our fan wired in directly to a switch for ease of maintenance. As you might have guessed we have the RP145 fan installed in the attic above our garage, and it is virtually silent.
As a side note, each fan comes with a suggested maximum operating pressure. This basically informs you how well your entire mitigation system is performing, how much pressure is being created by the fan, and whether you have sufficient airflow under the slab. To keep an eye on your system and to see that it is functioning nominally, I strongly suggest getting something like this Installation Kit for RadonAway System . It includes a manometer which basically tells you what pressure your system is holding. It’s inexpensive, easy to install, and well worth it. These kits also include couplings, which are intended to tie in your fan to the PVC piping(shown in the picture with the RP145 Fan) and I’d recommend using these, as they allow not only for a perfect tight fit with your piping, but also easy future fan replacement or maintenance.
Our radon levels in the basement were always hovering at around 25 and up to 31 pci/L, and around 20 pci/L on the main floor, during the cold winter months. Summers were ranging from 8 to 12 pci/L. After we installed the subslab mitigation system our levels are averaging 1.4 during the coldest months, and 0.4 to 0.8 pci/L in the summer. The picture to the right is from our own Safety Siren Pro 3 Radon Detector. Click on it to see a larger version. It was taken on January 31, 2010. We have been using it for over 2 years now, and had several of our neighbours borrow it for some time as well. If you find that you have a radon problem, you are probably better off getting one of these instead of the charcoal or alpha track test kits that need to be sent in to a lab. These are not cheap, they go for US $130.00, but they are very accurate and convenient to use.
If you are interested in prices or would like to purchase one, here are a couple of suppliers in the States. They also provide a lot of additional information about their products.
Radon Zone – These guys are offering free shipping, unfortunately they only ship to the States (sorry Canadian customers). They supply other, short and long term, radon test kits, as well as the Safety Siren Pro 3.
National Safety Products – These guys dont offer free shipping but they do ship to Canada, and they do offer discounts if you plan on purchasing more than one item. They also supply other radon products.
I wish you all the best and hope you get those radon levels down just like we did.
Pressurization uses a fan to blow air into the basement or living area from either upstairs or outdoors. The goal here is to create enough pressure (positive pressure) at the lowest level indoors, such as in a basement, to prevent radon from entering the house. The effectiveness of this technique can be limited by house construction and climate. In order to maintain enough pressure to keep radon out, the doors and windows at the lowest level must not be left opened, except for normal entry and exit. Blowing air out of the basement to reduce radon levels, although seemingly a good idea, might actually increase the flow of radon into your home. As you blow air out, a vacuum effect is created (negative pressure) which will cause greater influx of radon into your basement from the surrounding soil.
Another form of ventilation is natural ventilation, which is achieved simply by opening doors and windows at the lower levels of your home. Natural ventilation mixes outdoor air with the radon contaminated indoor air, thus reducing overall radon levels.
There are some obvious drawbacks to both of the above techniques. Once you close your windows and doors, or turn off your fan that blows air into your basement, radon concentrations most often return to previous values within about 12 hours. Furthermore, as a result of more outdoor air being introduced into the home, you might see moisture intrusions, loss of conditioned air, and energy penalties, particularly during the winter months.
Consequently, both of these techniques are regarded as only temporary approaches to radon reduction and should only be considered after the other, more-common techniques (such as sub-floor mitigation) have not sufficiently reduced radon levels.
Another form of mechanical ventilation can be accomplished by installing a heat recovery ventilator (HRV), sometimes referred to as air-to-air heat exchanger. HRVs ventilate by introducing outdoor air while using the heated or cooled air being exhausted to warm or cool the incoming air. The advantage of an HRV system over other ventilation techniques is that besides supplying balanced ventilation, a HRV will reduce the energy penalty associated with providing more ventilation to a home. As an added benefit, an HRV can improve air quality in houses that have other indoor pollutants.
Sealing the cracks in the foundation and other openings, such as drainage and sump pump sinks, is a basic part of most approaches to radon reduction. This technique reduces the flow of radon into your home thereby making other radon reduction techniques more effective and cost-efficient, and also reduces the loss of conditioned air. This technique, however, has its limitations. It is difficult to identify and permanently seal all the places where radon can enter, and if you have a finished basement, this is almost impossible without extensive and possibly expensive work. Furthermore, even if you were able to do so in an unfinished basement, normal settling of your house will eventually open new entry routes and reopen old ones.
You can try a special floor drain adapter for your drainage holes in your basement. I myself have purchased couple of these Dranjer D-R2 floor drains. They allow for water to flow down the drain but prevent any gas/air from coming up through it into the living space. According to the website I purchased these from it does the following: “Dranjer seals permit unrestricted flow of water into floor drains or sump pits while sealing out the entry of mold spores, insects and radon gas from the sub-slabe floor area.” To be completely honest, I am not sure these worked very well, as my radon detector did not register any significant changes.
As a side note: EPA does not recommend the use of sealing alone to reduce radon because, by itself, sealing has not been shown to lower radon levels significantly or consistently