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

News for Homebuyers Regarding Radon Resistant New Construction

Posted by Matthew Bednarz on Fri, Jun, 19, 2015 @ 16:06 PM


Home Buyers: Know What to Ask For

Basic Radon-Resistant New Construction Techniques for Your Home

Based on a rash of recent poorly engineered prefab radon system experiences, I felt it necessary to rehash an old post.  All of the techniques and materials described below are commonly used in home construction.  While the techniques may vary for different house foundations and building site requirements, the five basic features that should included in new construction to prevent radon from entering the home are:

cutaway of house with mitigation system
NOTE: If code allows; alternatives such as a soil gas collection mat can be a viable option.  
  1. Plastic Sheeting or Vapor Barrier / Retarder: Place heavy duty plastic sheeting (6 mil. polyethylene) or a vapor retarder on top of the gravel to prevent the soil gases from entering the house. The sheeting also keeps the concrete from clogging the gravel layer when the slab is poured.             

  2. A Vent Pipe: Run a 3-inch or 4-inch solid PVC pipe, vertically from the gravel layer (stubbed up when the slab is poured) through the house’s conditioned space and roof to safely vent radon and other soil gases outside above the house.  Whenever possible - 4" pipe is a better choice as it allows for up to double the volume of air to be removed out from under the slab as compared to 3".                                                        

  3. For very large footprints, multiple vertical stacks are recommended.  We did a project in a Greenwich estate that had 6 stacks. (Although serving a different purpose, this vent pipe is similar to the drain waste vent, DWV, installed by the plumber for the sanitary system.) This pipe should be labeled "Radon System."       

  4. Sealing and Caulking: Seal all openings, cracks, and crevices in the concrete foundation floor (including the slab perimeter; floor wall joint) and walls with polyurethane caulk to prevent radon and other soil gases from entering the home.                

  5. Junction Box:  An electrical outlet should be provided near the pipe location in the attic.  This is allows for easy fan connection in the event the system has to be activated to effectively reduce radon concentrations.

Some common mistakes made with radon resistant construction pipe installation are;
  • inaccessible attic locations (pipe located where no one can fit),
  • slab stubs located at opposite end of basement from ceiling stub (results in excessive pipe runs),  
  • multiple slab level layouts not being addressed.
Homes located in areas that have water wells should have a second or independent stack installed from the basement ceiling as close to the well tank as possible, to the attic floor.  In the event the water is found to have elevated radon levels, an aeration system will need to be installed.  This system requires a separate exhaust stack.


Topics: radon resistant construction, radon mitigation, radon in air, radon mitigation system, radon testing, radon in air concentrations, indoor radon in air levels, Radon Air, radon mitigation fan, radon concentrations


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 Mon, Mar, 17, 2014 @ 14:03 PM



radon testing during a real estate transaction


Radon testing is a standard offering from most any reputable home inspector.  As a result, Realtors are inevitably impacted when a radon problem is uncovered in a home that has been inspected as part of a real estate purchase / transaction.  But there are times when radon should never become an issue.

What Realtors need to know about radon is that improper radon testing procedures probably account for more lost sales, closing delays, and animosity between buyers and sellers, than any other environmental issue encountered during a real estate transaction.  An educated Realtor can be proactive in avoiding the many pitfalls a poorly executed radon test can create.  Radon testing performed as part of a home inspection during a sales transaction should be done in a manner that will reveal what the home's occupants will be exposed to on a consistent basis, under normal living situations. These "screening" measurements should not be used to get the highest radon reading possible.

dirt floor basement

Non livable dirt basement

Erroneous radon test device placement is easy to recognize once you know what to look for. Placing a test kit in a crawl space, sump hole, or a dirt floored coal cellar that you have to crouch in, is not the proper location for a screening measurement for radon!  Here are the basic EPA guidelines for testing:

  • Test devices should be placed a minimum 20" off the floor.
  • Test devices should not be placed near vents, doors, & windows.
  • Test devices should not be placed on furnaces & hot water heaters.
  • Test devices should be a minimum of 3 ft. away from doors & windows.
  • Test devices should be a minimum of 1 ft. away from exterior walls.
  • Testing should not be performed in kitchens, baths, & laundry rooms if at all possible. 

 Incomplete radon testing of homes with expanded footprints (homes with first floor additions or liveable areas not located over the basement) can also create problems during the course of a home sales transaction.  Homes with footprints that extend beyond just the basement need to have more than one area tested.  As an example; a home with a full basement that has a family room addition built over a crawl space, and a master bedroom suite built "slab on grade", should have all these areas tested. 

additions should be tested for radon

Addition on slab

What Realtors need to know about radon is that if an elevated radon level is found, a qualified mitigator who surveys the home to give a radon mitigation quote will recognize that these other areas need to be tested in order to give the most thorough assessment of the radon picture for the home.  The experienced radon mitigator will recognize that oftentimes; mitigation efforts made in one location of the home, will have little to no impact in other areas of the home.  To avoid delays and jeopardize closing dates, it should be determined in advance if those other areas need to be addressed. That can only be ascertained by thourough radon testing procedures. 

If the home being tested for radon in air has well water, the water should be tested for radon.  Radon in water testing needs to be requested by interested parties, because it is not included in a standard potability analysis.  The radon content of water can impact radon in air levels.  Sometimes; a radon in water level can be a major contributing factor to an elevated radon in air concentration. 

Stack effect


What Realtors Need To Know About Radon:
*Radon levels are in a constant state of fluctuation (in both air & water).
*Radon entry into a structure from the soil is greatly influenced by pressure differentials that develop between the interior & exterior of the structure.
*Exposed ledge or dirt in a basement doesn’t automatically indicate the home will have a radon problem.  A radium source in the rock or soil is necessary for that rock and soil to be a contributing factor to an indoor radon in air problem. 
*Airborne radon levels are higher in winter due mainly to the “stack effect”.  The stack effect occurs when heated air inside the structure moves vertically through the structure.  The envelope of the heated structure creates a vacuum or suction on the ground on which it sits.  This increases the influx of radon laden soil gas into the structure.
*A house closed up for a long period of time doesn’t continuously build up radon concentrations.  There are two reasons for this.  Reason # 1:  Radon's half life.   Since radon is radioactive, it has a "half life" or natural decay process.  Every 3.8 days, half of any radon level dissipates...decays away...all on it's own.  Radon enters the home, but also dissipates on a consistent basis.  Reason # 2:  Natural Ventilation Rate (NVR). Regardless of the age of a home, air infiltrates in and exfiltrates out of the home continuously.  Therefore, even a home that has been closed for two years doesn't have two year old air inside.
*All occupiable areas of multi level homes should be tested...not just the basement!
Contact us for Radon  Information
certified radon mitigator

Topics: radon in water, radon in air, radon testing, radon in water testing


Posted by Matthew Bednarz on Tue, Jul, 16, 2013 @ 17:07 PM


radon and water quality testing

Radon testing for real estate transactions can oftentimes become a contentious issue if not administered properly.  It is also critical that the Interpretation of any test results be handled judiciously to ensure that unnecessary work, delays in closing, and buyer / seller stress be kept to a minimum.  I'm rehasing this info because the real estate market is quite active right now and the issue of improper testing procedure is once again becoming commonplace in the real estate market!

Radon testing for real estate transactions should be conducted by someone who has a NRPP or NRSB certification for radon testing.  Aside from the certification;  a common sense approach is helpful in the deployment and retrieval of test devices.  The most common error we see in the field are homes that have been insufficiently tested for radon in air. 

An illustration of this scenario would be a 5,000 square foot home with a portion of the structure over a basement, a portion over crawl space, and a portion that is built slab on grade.  The elementary approach many test "professionals" would take would be to test the basement only.  The problem is that the results achieved in that area are not representative of the radon levels in the rest of the home.  The basement can yield very different results vs. the section of the home that is "slab on grade".  Left untested; the occupants may end up unknowingly exposed to elevated radon concentrations in areas where they spend measureable time.

hallway 3 resized 600   house cutaway resized 600

Homes bought and sold during the spring and summer markets may test "low" for indoor radon concentrations.  However; the "stack effect" which occurs in all homes to some degree during colder weather, can sometimes dramatically increase indoor radon concentrations.  The message here is to retest for radon in air concentrations periodically, with an emphasis on a "cold weather" result included in the mix.  Many homeowners are lulled into a false sense of security by one low result and spend years unknowingly exposed to elevated radon concentrations.

When contracting a testing company (or home inspector) to test the home you're interested in; you should emphasize the fact that you want the home tested so that you know what your family's exposure will be throughout the home...not what the radon level is in a sump hole or crawl space!

Radon testing for real estate transactions should also include a radon in water test if that water comes from a private water well.  A low radon in air concentration in the basement or lowest living level of the home does not mean there isn't a radon problem in the water.  Conversely; a high radon level in the upper portion of the home vs. a low reading in the basement is a clear sign of a source (off gassing of radon) in the water.  After the closing and long after all the inspections are completed, be sure to test the water regularly.  Potability at least annually.  Radon & other "special request" bi - annually.

Radon testing for real estate transactions should include at least on dual device test result if passive detectors such as charcoal canisters or e-perms are utilized. Only one Continuous monitor device is required for the area to be tested.  If an inspector only has one device & the home has multiple areas to be tested; passive detectors can be deployed simultaneously in the other areas to be tested.

radon test devices




Contact us for Radon Testing  in Air & Water


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Topics: radon in water, radon in air, radon testing

Radon Testing

Posted by Matthew Bednarz on Mon, Oct, 22, 2012 @ 10:10 AM

radon testing

                                                           RADON TESTING

Radon testing is a common component of the real estate inspection process during a home sale.  However; homeowners who are not selling their homes should also test for radon!  Whether you think the health risks associated with radon exposure are real or not; you should know what your radon levels are so that you're not "blindsided" by a radon problem when you do decide to sell.

The following bullet points are extracted directly from EPA radon testing protocol.  Realtors should take note to ensure your buyers are getting the full value of the tests they're paying for. If you have a real estate listing that's being tested, there are also things / circumstances to beware of to ensure your seller doesn't face frivolous or unneeded repair bills.

  • EPA protocol requires that radon testing for a real estate transaction be performed with "dual devices" or duplicates. 
  • Two of the same testing devices should be placed side by side in the lowest liveable level of the home.
  • Test devices should be 20" minimum off the floor, away from drafts.
  • Test devices should be 3 feet away from doors and windows.
  • test devices should be at least 1 foot away from an exterior wall. This applies to any passive test devices.
  • The dual device requirement does not apply to continuous monitors that can integrate & record new results hourly.
  • Radon test devices should not be placed in a sump hole, on the floor, in a crawl space, on a furnace, in an active kitchen or bath, or on a window sill.
  • Radon testing should not be conducted during times of high winds or stormy weather as these conditions will create a momentary spike in radon concentrations.
  • The minimum test period for real estate screening measurements is 48 hours...a 2 hour grace period is acceptable. This includes continuous monitors.  A 24 hour continuous monitor test IS NOT sufficient.
  • The home or area to be tested should be closed 12 hours prior to the start of the test, & remain closed for the duration of the test. Normal entry & exit is acceptable, as is occupying the areas during testing, provided the test devices are not disturbed. Dehumidifiers are allowed to operate during a radon test as is air conditioning, as long as interior air is circulated - not exchanged, with exterior air.
  • The operation of attic fans, fireplaces, range hoods, clothes dryers & wood burning stoves should be avoided during a radon test.  This is because the operation of these appliances can cause negative pressure to develop within a structure and create a spike in radon concentrations. 


 radon testing devices

The idea behind testing is to find out what the occupants of a structure are potentially exposed to on a consistent basis...the purpose of radon testing is not to get the highest possible result!

We recommend you request to see if the radon tester has acquired a radon testing certification from either NEHAor NRSB. If they don't have either accreditation; consider hiring someone who does. While certification doesn't guarantee proper testing procedures will be followed, it does give some indication of the tester's level of commitment to providing a quality testing service.   

Radon testing is really not all that complicated. But simple missteps can jeopardize even the most amicable real estate transactions.  The decision to mitigate should not be made on the basis of one elevated radon test result.  If you've already mitigated your home for radon...you should still retest at least every 2 years.  If you've only tested your home in spring / summer; you should test during the winter months as the results can be very different.

NEHA certified radon tester

Topics: EPA protocol, dual device testing, radon testing, real estate screening measurement