It’s possible a home inspection will reveal the existence of radon gas seeping up through the ground into the living area of the home you want to buy. Radon is known for causing lung cancer, so you don’t want it around. What can you do to decrease the seriousness of the problem? In other words, what do you do to mitigate the radon threat?
Radon resistant techniques can be simple and passive and will lower radon levels when done properly. They can lower levels of moisture and other soil gasses, too. Radon resistant techniques have the additional benefit of making your home more energy efficient and can help you save on energy costs. Save money when a home is first built by not having to deal with the problem later if these techniques are put into place with common building materials.
Even in a new home, radon testing should be done to be sure the level is below 4 pCi/L. If radon levels are high, a passive system can be turned into what’s called an active system by adding a vent fan to reduce radon levels.
You’ll need to find someone who is considered to be a qualified radon mitigator to install radon resistant techniques, whether your home is new or not. Costs will vary, but should be similar to other home repairs you may need to have done.
What are these radon resistant techniques? It’s important to note that this depends on your home’s foundation. Also, if you’re having a house built, ask your builder if they’re using EPA’s recommended approach.
The first radon resistant technique of note is a gas-permeable layer, which is used only in homes with casement and slab-on-grade foundations. It is not used in homes with crawlspace foundations. It usually consists of a four inch layer of clean gravel placed under the slab or flooring system. It’s meant to allow the gas to move freely under the house. Plastic sheeting is placed on top of the gas permeable layer and under the slab to help prevent the soil gas from getting into the home
When a home has crawl spaces, plastic sheeting is placed over the crawlspace floor. This serves as a moisture barrier as well.
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Sealing and caulking is another technique. Any below-grade openings in the concrete foundation floor are sealed to reduce the amount of soil gases getting into the home.
When there’s a gas-permeable layer under the home, a vent pipe is put into the gravel and runs through the house and to the roof to vent gases away from the living area. The pipe used is a 3- or 4-inch gas-tight or PVC pipe, or other gas-tight pipe.
If it’s necessary to use a vent fan to reduce high radon levels, an electrical junction box is included in the attic to make the wiring and installation of a vent fan easier. A separate junction box is put in the living space to power the vent fan alarm. That’s because an alarm is installed along the vent fan to indicate when that fan isn’t operating properly.
Your home inspector or other qualified radon mitigation professional should know the best place to put radon test equipment. It should go into the lowest level of the home that’s occupied regularly, such as any place used as a bedroom, play or exercise area, den or workshop. The EPA says testing should not be done in a closet, stairway, hallway, crawl space or in an enclosed area where there’s either high humidity or breezy air circulation. Avoid places like the kitchen, laundry room,bathroom or furnace room.
There’s no way to accurately know the level of radon in the home you’re building, buying or selling unless radon testing is done. Be sure your home inspector or other qualified professional can do the testing for you. You don’t have to put your family’s health at risk from radon.
You’ve carefully selected the home you’re buying. Make sure you’re as careful when selecting your home inspector. Don’t get stuck paying for repairs missed by a quick home inspection. Author David Haigh is a professional home inspector in NJ. Click now to view a free sample report of a New Jersey home inspection.
One of the major health hazards and Radon dangers that are often present in an invisible, odorless as well as tasteless manner is the presence of Radon in a building which is a danger that needs to be removed and eliminated without delay if you don’t want to end up suffering from lung cancer. Mostly, radon gets into a building through the floor and to reduce the risks you can either try or prevent the Radon gas from entering the building, or you can extract it from the building.
The best Radon remediation technique is the one that addresses a particular instance of Radon presence in the building, and so you may need to choose one or combination of methods to get rid of Radon in the home. However, the easiest way is preventive Radon remediation for which you would need to seal all gaps and cracks as well as the joints under the building’s floors. For this method to succeed, you need to ensure that you can seal everything so that no Radon gas can enter into the home.
You can also use extractive Radon remediation techniques, which are sometimes known as soil suction and which is a very common method of remediation in which you need to make use of cavities that are of the size of a bucket and which are called sumps. These cavities can be connected to a pipe network that leads out of the building. Furthermore, the sump helps in changing pressure differentials between the interior of the building and its exterior through lowering the pressure in the building’s exterior. With the help of a fan, the air below the building is sent into a pipe system and thus extracted out of the building.
This may be a slightly more expensive Radon remediation technique, but it is certainly very effective and thus well worth choosing.
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Radon is a colorless, odorless, tasteless radioactive gas that is a decay product of uranium that naturally occurs in soil and rock. The 2nd leading cause of lung cancer, Radon causes 15,000 to 21,000 deaths in the United States annually and has been found and identified in every state. Once produced, radon moves through the ground to the air above while portion remains in the earth and dissolves in underground water. It is estimated that over 6% of every home in the United States has elevated levels of radon that may need remediation. The Environmental Protection Agency and many state governments recommends Radon testing. The EPA states that any Radon exposure carries some risk. Radon levels are measured in picocuries. A picocurie (pCi) is a measure of the rate of radioactive decay of Radon. Remediation is suggested if the levels average 4 picocuries per liter or higher ( pCi/L) Unless Radon is tested for, there is no way of knowing how much Radon is present. Some states require radon testing for real estate transactions including property transfer or for mortgage approval on a planned property purchase. If Radon levels are not within an acceptable range within a planned purchase, ventilation remediation may be required before the sale will go through.
Only smoking causes more cases of lung cancer than does Radon exposure. If you smoke and are exposed to higher than normal Radon levels your risk of lung cancer is elevated. The Environmental Protection Agency (EPA) has a Radon risk comparison chart available for those who smoke and who have never smoked. The problem is that Radon gas decays into radioactive particles that can become trapped in your lungs. Over the course of a lifetime, lung tissue may become damaged. Breathing of Radon does not cause any short-term bad health effects such as fever, headaches or shortness of breath and everyone that is exposed to high radon levels will not develop lung cancer, but the potential risk is higher than usual. Radon in drinking water also poses some risk, but research shows those risks are much lower than those risks from breathing radon in the air.
Most indoor Radon comes into a building from the soil or rock beneath it. The Radon becomes trapped under a building and builds up pressure. The built up pressure forces the gases through cracks and other openings in a building and become concentrated. Because Radon levels are not predictable, it is wise to purchase an inexpensive Radon test to determine if levels are unacceptable in a home or building.
What is the Radon testing procedure?
Radon testing is inexpensive and easy. To perform a radon test simply follow the instructions provided and return the radon sampling bag in the self-addressed envelope. All that is required to collect the sample is to open the package and place the sampler in the area to be tested. The test start date and time and the completion date and time are recorded on the supplied data card that is returned with the collected sample. The sampler should be exposed to the environment in the area being tested for 2 days. The cost of the kit includes a laboratory analysis fee and the detailed report, which will be sent to you.
The Report Includes The Information On: Report Date, EPA ID Number, State ID #, Lab ID #, Kit ID #, Radon Level Measured (pCi/L), Test Location, Test Type, Start and Stop Date and Time, Test Method, Radon Health Risk, Explanation of results, Recommended next steps required based on radon level.
Be Proactive. Don’t wait until someone falls ill, or you are contemplating selling your home to test the levels of Radon in your residence. Stay healthy, Be Safe.
The author is the owner and founder of Be Safe Plus LLC, an e-commerce website that specializes in Safety, Wellness, Sports Therapy and Exercise products and solutions including Radon testing kits.
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