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 Fri, Jul, 25, 2014 @ 15:07 PM


 Environmental Testing

Environmental testing for real estate transactions can become a contentious issue if administered improperly.  The negative impact can be further exacerbated by an erroneous interpretation of results.  Comments made by disgruntled property owners such as; "we've lived in the home for years and we're still here!" serve no useful purpose, and prove nothing more than they've been blessed with good genes...it doesn't mean that radon, arsenic, or whatever environmental contaminant in question isn't harmful.  We do not offer abatement services for mold or asbestos, so this article will focus on our areas of expertise.  

  Radon in air, radon in water, general water quality (potability), and "exotic" contaminants such as uranium, arsenic, and Volatile Organic Compounds (VOC's) in drinking water are just some of the environmental issues that can turn an otherwise amicable property sale into a contentious transaction.  Overall property values will be negatively impacted if these problems are severe enough...not to mention the potential health ramifications to the home's occupants if left unchecked.  Mold & asbestos are examples of other environmental hazards lurking in homes.  

The statement: "Timing is everything" is true for many situations we encounter in everyday life.  This is also true when talking about environmental testing for real estate transactions.  As an example; Climatic conditions prior to - and during an airborne radon test can have a dramatic affect on the test results.  A thunderstorm with high winds will create a substantial spike in airborne radon concentrations.  A clear, calm, mild stretch of weather will yield the lowest possible results.  Winter conditions will yield higher airborne radon concentrations vs. summer like weather due to the "stack effect".

stack effect

The impact to well water quality from climatic conditions is less predictable.  Sometimes a water well can demonstrate an almost instant "change" from a passing a rainstorm...or climatic "event" (ie; pH drops down).  Other times it may take weeks or months for changes - if any - to occur.  Regardless of any climatic events...ground water is "ever changing", and therefore should be tested on a regular consistent basis.  Geologic shifts, extended periods of rain...or lack thereof, can influence what's happening down at the aquifier level.

 There are no filters or control valves down in the ground that allow only water of a certain quality to enter your well.  The well pump draws water in from the surrounding rock strata & pushes it up and into to your home. If, before getting drawn into the pump, the water flows through an arsenic, uranium, or radon bearing source, the more of a chance it will have an elevated presence of that contaminant.


Environmental testing for real estate transactions should also be testing that a homeowner does periodically throughout their residency in that home...not just at time of purchase.  Just like you maintain your furnace, kitchen appliances, or water conditioning equipment; a regular check on environmental hazards in the home is just another sensible "chore" a homeowner should undertake periodically. 







Topics: radon in water, radon in air, arsenic, potability, well water, water quality


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!
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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




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