CT Basement Systems Radon Blog by Matthew A. Bednarz V.P.


Posted by Matthew Bednarz on Thu, Jan, 18, 2018 @ 14:01 PM

January is Radon Action Month (RAM).  January was chosen as RAM primarily because indoor radon concentrations are at their "worst case" or highest levels for the year.  Radon entry into buildings is based on pressure differentials.  These pressure differentials are exacerbated during the heating season due to the "stack effect".  The stack effect is a scenario whereby heated air rises within a structure via thermal bypasses, which induces the structure to increase suction on the ground on which it sits.  This in-turn, increases the influx of soil gas into the structure, thereby increasing airborne radon concentrations.


Testing airborne radon concentrations this time of year will generally give a "worst case" scenario for radon.  Point being; if your radon testing indicates levels > 4 pCi/l, the likelihood that your annual average is going to be below 4.0 pCi/l is very good.  On the other hand, if your radon levels are > 4 pCi/l, this gives indication that at the very least; further testing is warranted.  Radon mitigation should never be based on one result.  But the higher above 4.0 pCi/l you are, the more confident you can become that there is a problem. 

There's an old saying that states; "no news is good news"...maybe it would be if something different was discovered about radon exposure that indicated it was less of a problem than originally thought.  The reality; nothings changed.  Radon is still recognized as the leading cause of lung cancer in non-smokers, and the second cause of lung cancer overall.  It's the intangible aspect of radon that make events like RAM necessary...to remind us of the hidden danger.

The other facet of radon that is sometimes overlooked - but is still important to consider  is waterborne radon.  For those of us whose daily water usage is supplied from a private drinking water well, radon has a second "highway" into your home.  When you test your air for radon - you should also test the water.  As is the case with any water contaminant, waterborne radon levels can fluctuate.  A low reading 3, 8, 11 years ago in no way assures a low reading going forward.


Contact us for Radon Testing  in Air & Water





Topics: waterborne radon removal, radon, soil gas


Posted by Matthew Bednarz on Tue, Jan, 20, 2015 @ 10:01 AM


 radon testing

January is RADON ACTION MONTH in the United States.  With the holiday season behind us, we're staring winter square in the face. It's a good time to think about testing your home for radon.  Even if you have a radon in air mitigation system, the EPA recommends follow up testing every two years.  There is no "safe" level of radon.  In fact, there's an associated risk of lung cancer with exposure to any level of radon.  The EPA's 4.0 pCi/l Action Level is a level at which to take "ACTION" to reduce radon concentrations and reduce exposure risk...it IS NOT a "safe level"!

describe the image

 Radon in air concentrations fluctuate in direct correlation with weather conditions.  Winter time is "worst case" scenario for radon testing due in large part to the "stack effect". 


stack effect RADON ACTION MONTH gives us an opportunity to think about radon exposure and the threat it presents to our families and loved ones...at a time of year when we are most likely to be exposed to the highest radon concentrations for the longest periods of time.  If the home has a private water well as its' water source...the water should also be tested for radon in water concentrations.

Many home owners have the misconception that one radon test below 4.0 pCi/l indicates a  "radon free" home.  This flawed thinking translates into countless cases of unintended exposure to elevated radon concentrations by unsuspecting home owners and their families.  Many of these victims of circumstance can trace their unrealized exposure dilemma back to the purchase of their home. " But when we bought the home - there was no radon" is a phrase that is all too commonly recited by disenchanted homeowners selling their home and having to mitigate elevated radon levels before they can close the sales transaction.

The largest percentage of homes mitigated for radon are a result of the home inspection process during a real estate transaction.  Paradoxically, the largest number of unsuspecting homeowners being exposed to elevated radon levels on a yearly basis are a result of the home sale / inspection process. Here's why...

 Home inspections are an integral component of the real estate transaction process. Radon testing (or a real estate radon screening measurement) is part of this process.  When a "for sale" home tests high for radon... most often it is mitigated before title is transfered.  When considering that the real estate market - in general - realizes maximum sales volume in spring and summer, many of these home inspections yield "low" or "lower" radon screening results simply because of the time of year the home is being tested (inspected - sold). 

Unfortunately, most homeowners never bother to follow up with a cold weather radon test. This oftentimes results in homeowners being exposed to elevated radon concentrations (albeit for a portion of the year) for as long as they own their home, because they have been lulled into a false sense of security by the one low result they got at the time of the original inspection / test.  

radon testing devices

Radon is a class 1 carcinogen...it is the number one source of lung cancer in non - smokers, is naturally occuring, is on the periodic table of elements, is found everywhere to some degree, is colorless, odorless, and tasteless, is easy to test for, is fixable...and most importantly - IS REAL!  It's RADON ACTION MONTH...  TAKE ACTION! - test your home today! 



certified radon mitigator and testor

Topics: radon, radon mitigation system, radon testing, radon in air concentrations, real estate screening measurements, radon action month

Radon Map of CT

Posted by Matthew Bednarz on Tue, Jul, 01, 2014 @ 13:07 PM

 Test for Radon

The Radon Map of CT only begins to tell the story of the prevalence of radon in the state of Connecticut.  CT Basement Systems Radon Inc. has been in the radon mitigation and radon testing business since since 1987.  Through the years, we have seen many homes test "high" for radon in zones or counties where the radon "potential" was thought to be lower.  Conversely, we have have tested many homes that resulted in radon levels below 4.0 pCi/l in areas designated as having a higher radon potential.

 CT Radon Map

radon masp legend

While the Radon Map of CT may be useful as an introductory tool for radon risk assessment, it should not be the only benchmark utilized in determining whether or not a home has a radon problem.  Radon is a very "site specific" danger.  We have seen streets in neighborhoods where 9 out of 10 homes have elevated indoor radon in air levels.  We have also seen neighborhoods where only one or two homes out of 20 have elevated airborne radon levels.  Much the same can be said for radon in water levels.  A neighborhood of homes with private water wells can have a wide range of waterborne radon levels even though the wells are within close proximity to one another.

Variation in airborne radon levels is not something limited to only larger tracts of real estate.  I have personally tested homes that have shown variations of up to 100 pCi/l from one end of the home to the other at the very same time of testing.  We attribute these variations to differences in soil composition that the home is built.  Radon (and radium) are part of the Uranium 238 decay chain.  It is possible to have a structure with a sufficient enough of a footprint, to cover a piece of real estate that has a significant variable in its' radium content; thereby resulting in appreciable differences in airborne radon concentrations. 

The topography of a given piece of land is not a good indicator of the "radon potential" for the structure to be built on it.  Ledge and rock are not reliable barometers for scoping out potential radon problem areas.  I have tested plenty of homes with exposed ledge outcroppings within the structure...and have had numerous test results yielding radon concentrations <4.0 pCi/l.  As a company, we mitigated a home in Glastonbury CT, with indoor airborne radon levels of 900 pCi/l...yet Glastonbury is located in a "low radon potential" area on the Radon Map of CT.  The only way to know is test your home!  Don't forget - if your home has a private water well...test the water for radon also!

 Contact us for Radon  Information

NEHA Certified Radon Tester 

Topics: radon, radon testing, indoor radon in air levels, airborne radon, radon concentrations


Posted by Matthew Bednarz on Wed, Sep, 05, 2012 @ 14:09 PM

radon mitigation systems

Active Soil Depressurization (ASD) is the most common radon mitigation system or technique utilized to mitigate elevated airborne radon concentrations. The installation process involves installing PVC pipe through the slab of the structure, and routing the pipe up to the roofline of the structure.  An in-line fan is connected to the pipe.  This in-line fan creates a suction or negative pressure on the sub slab fill thereby intercepting radon and soil gas before it has a chance to permeate up through the slab.  The radon and soil gas is vented safely outdoors, above roof line.      


ASD system routes

ASD is the most commonly employed radon mitigation technique because of cost, effectiveness, and relative unobtrusiveness.  The most common way to install an ASD system is the exterior route option.  This involves the fan being positioned on the exterior with the vent routed to the roofline up the exterior of the building.  This routing is most common mainly because a larger percentage of radon mitigation work is paid for by the seller of a property during a real estate transaction.  very often, an ASD system can be positioned on a portion of the structure that is considered utilitarian.  However; this isn't always the case. 


Exterior route ASD system resized 600 

Since an ASD system becomes a permanent fixture in a home; some consideration should be given to potential route options that might exist for the ASD installation.  An interior or garage route are oftentimes available, but overlooked due to increased install expense.  On average; a garage or interior route option adds about 20% overall expense to the install.  Not significant when considering an average ASD install expense of $1,200 and the fact this is a permanent fixture in a home or building.

If you're purchasing a home that needs a system; get involved in the decision process!  The seller's responsibility is to get the radon levels down - not necessarily to give you the prettiest install possible.  If you're having a system installed for the benefit of your own family, consider future resale value.  Radon fans are made to be mounted externally; but if it can be shielded from sun & ice - why not?  

This is the very reason why we visit the jobsite to quote on ASD installs.  Nuances such as; view from the road, window locations, roof pitch, electrical availability, access in basement, and a multitude of other factors simply cannot be determined by a phone conversation.  Old tag lines such as; "we've done plenty of work in your neighborhood" or "area" simply don't hold water. 

Sometimes there's no choice but to route the system externally.  We can do everything we can to minimize aesthetic impact.  Remember that there are oftentimes alternative route options or locations. In most cases - it is well worth exploring these alternatives for your radon mitigation system installation. 

exterior route ASD system

 certified radon mitigator


Topics: airborne radon concentrations, radon, radon mitigation system, active soil depressurization, ASD, radon fan

Radon Resistant New Construction

Posted by Matthew Bednarz on Mon, Jul, 30, 2012 @ 16:07 PM

Radon Resistant New Construction (edit/delete)

Radon Mitigation

Radon resistant new construction is becoming an accepted process by more & more home builders.  There is much misinformation in the marketplace regarding radon...especially regarding new homes.  A common misconception is; radon doesn't exist in new construction.

 Age of a structure can sometimes play a role in determining whether or not there will be a radon problem...but most often, it is not a critical factor. Theoretically; older structures that have substantial air leakage should have lower indoor airborne radon concentrations than newer energy efficient homes. The natural ventilation rate of a leaky home helps dilute down radon concentrations. However, if the radon source is strong enough - even a "leaky" or "energy inefficient" home will still have a radon problem.

It is not possible to completely eliminate radon from entering a new structure.  However; during the early stages of construction - there are radon resistant building practices that can be taken to help "build radon out"...& keep radon concentrations lower than if nothing were done.

 Before the slab is poured, a network of perforated pipe is laid out across the future slab area of the new structure.  There are many pipe configuration variations that can be utilized.  The pic below illustrates a new school we did where the architect required prefab suction boxes with vapor barrier laid under & over the gravel bed.  Whichever pipe configuration is chosen; a stub is connected somewhere in line of this sub slab pipe run.  This stub will be the connection point for a future active radon system if needed.  It is best to try to keep the stub location as close as possible to the intended future vertical pipe run. The new basement floor or slab is poured over the barrier. The new slab is allowed to cure. After curing, any expansion joints, cracks, & the floor wall joint should be sealed with a urethane caulk.

sub slab pipe network

 Once framing has been completed, pipe is connected to the stub that is protruding from the slab, & is routed up through the framed structure, & roof. It is preferable to run the pipe up through the structure in an interior wall to maximize convection . The more streamline the pipe run - the more air that is able to be pulled out from under the slab.  the pipe should penetrate the roof sheathing before the new shingle is installed.

 The other important aspect to keep in mind is where the pipe enters the attic. It will hopefully be located in an area that will remain accessible even after duct work & air handlers have been installed. This becomes key if a radon mitigation fan unit is to be connected to the pipe. Also, there should be 3 feet of vertical / accessible pipe available in the attic to allow for a fan installation if needed.


Interior Route ASD System Interior Route ASD System

After the structure is "conditioned"...it should be tested for radon...this is true even if other new homes in the same area were found not to have a problem.  If a problem is found; a sealed fan can be connected to the pipe in the attic which will create a very effective negative pressure field under the new slab that will prevent soil gas & radon from permeating upward. The active system will also contribute to reducing moisture levels in the basement. The system will be effective & inconspicuous.

 If the home has a private water well, remember to run a second pipe to the attic from a location as close to where the well tank will be positioned in the basement as possible. If a high waterborne radon level is found, an aeration system will be needed to mitigate the radon in water problem.  This system also requires a vent to the exterior. That secondary pipe can be utilized as an exhaust for a future aeration system.  If no problem is detected...the pipe makes for a convenient wire chase.

Radon resistant new construction practices are an important tool for the modern homebuilder.  Aside from preventing radon entry; these procedures ultimately provide a higher degree of comfort - both psychologically & physically - for the new home owner.  Dampness control, better aesthetics, greater reduction efficiencies are all byproducts of a well executed radon resistant construction strategy. There's simply no need to have exposed pipe on the outside of new structures if some forethought is put into design. 

describe the image 



Topics: ventilation rate, negative pressure, radon resistant construction, well tank, radon, waterborne radon, airborne radon, soil gas, radon mitigation fan, radon fan

Indoor Airborne Radon Concentrations

Posted by Matthew Bednarz on Tue, Jun, 26, 2012 @ 11:06 AM


Airborne Radon Mitigation

Climatic conditions have a great affect on indoor airborne radon concentrations.  Radon entry into a home via the soil is predicated on pressure differentials that exist - or that are developed - between the interior & exterior of the home.  Low barometric pressure (the kind of atmospheric pressure that typically accompanies adverse weather) will allow for greater influx of soil gas - hence, radon...into the structure.

A rainstorm will not only include this drop in atmospheric pressure, but will oftentimes include winds that increase pressure differentials within a building. Saturated soil that prohibits the natural flow of soil gas from emanating through the lawn surrounding the house to redirecting flow into the basement is another contributing factor to spikes in indoor airborne radon concentrations.

If rainfall is substantial enough, a troublesome remnant will be saturated soil under the basement slab.  since a typical Active Soil Depressurization (ASD) system relies on creating suction / air movement below a basement slab to mitigate radon; damp or wet sub slab material will impede the radon mitigation system's ability to create a successful sub slab pressure field.  This may be a temporary occurrence or it may be a permanent change due to geologic shifts, changes in landscape, etc.

If a radon mitigation system seems to periodically get louder - or a "swishing sound" can be heard emanating from the pipe; this may be indicative of saturated soil conditions under the slab.  Homeowners should beware that during these conditions; reduction capabilities of the mitigation system are likely diminished.  If this scenario becomes commonplace; the homeowner should strongly consider installing a sump pump and possibly some draintile to help lower the water table under the slab.  This may even become necessary in basements where there is no previous sign of water infiltration.  Water is problematic for ASD systems and can impact indoor airborne radon concentrations.

NEHA Certified Radon Mitigator

Topics: airborne radon concentrations, pressure differentials, radon, radon mitigation system, active soil depressurization, ASD, mitigate

Waterborne Radon

Posted by Matthew Bednarz on Wed, Jun, 13, 2012 @ 13:06 PM

Radon Water Mitigation

Waterborne radon is a secondary entry route for radon into a home - in extreme cases, it can be the primary source. Most all groundwater contains some level of radon because radium - a naturally occurring element that is part of the radon decay chain...is so widely dispersed throughout the earth's crust.

Radon in water testing is not part of a standard potability analysis (at least not here in CT) & therefore; a homeowner or buyer who is having the water tested must specifically request radon be included in the test. As is the case with other groundwater contaminants, radon is in a constant state of flux.  This is due in large part to what the water is exposed to as it travels to your well. Therefore; a mitigation strategy is best developed on the basis of multiple test results. Unlike airborne radon where ASD is used almost exclusively regardless of radon concentration; the amount of radon in water dictates what can be done for removal.

GAC with Pre & Post Sediment Filter Bubble Up Aeration Systems AiRaider


Unfortunately, time constraints in a real estate transaction typically don't allow for repeated rounds of testing. The best advice I can give is to size the treatment for worst case scenario. In the long run; an undersized or mis-applied technology will be more problematic than a treatment scheme considered to be "overkill".

 To help account for some quality control, the State of CT requires a dual sample to be collected when screening for waterborne radon as part of a real estate transaction. While this doesn't account for seasonal, climatic, or usage variations, at least dual samples help give a feel for the range of fluctuation of radon at the point in time the samples were collected. Point is: if initial readings are in the 100K range ( ie;90K & 110K respectively)...no matter what other readings are recorded - knowing the levels can spike that high would preclude the use of activated carbon in that particular situation.

One cannot assume there is a problem in the water based on an indoor air reading being elevated. However; there are certain circumstances that can identify potential waterborne radon problems. The following examples are actual field experiences;

Case #1) A colonial's basement & second floor master bedroom are simultaneously tested for radon. The basement result is < 4.0pCi/l, the master tests at 8 pCi/l...this indicates an offgas from the master shower (the water in this example ended up testing at 150,000 pCi/l!).

Case #2) A home listed for sale with a basement laundry room has a basement airborne radon test performed by an inspector with a 25 pCi/l reading. The homeowner contracts a mitigator (Not Us!) to install a mitigation system. The system is installed & retest results are at 22.5 pCi/l. The contractor returns & modifies the original system...retest results are 26.2 pCi/l...closing is delayed...contractor returns & you guessed it!...fails to get levels down...contractor refuses to return. We are contracted to fix problem & discover that the well water concentration in this home is over 200k pCi/l. An aeration system to mitigate the radon in water is installed...subsequent air tests indicate radon levels <2.0 pCi/l. Fortunately, upon our assurances, buyers didn't walk & eventually closed on the property.



certified water specialist, certified radon mitigator


Topics: radon in water, radon, waterborne radon, dual sample, potability