Radon; psuedo science or fact?
When you live in a place as beautiful as Colorado you rarely think about what lies beneath
unless you’re living over an abandoned mine. In fact few of us know that our state is
considered a level 1 radon state; http://co-radon.info which means the majority of structures
may have unhealthy levels of the gas creeping in from high levels of naturally occurring
radium in the soil. When you’re living over decomposed granite theoretically you will be
exposed to some. It’s difficult to say how much without performing a simple test.
Radium is born out of the decomposition process of uranium, one of the most radioactively
toxic substances on our planet yet it’s hard to imagine Pikes Peak as one large isotope
without a degree in geology and particle physics. The EPA has Radon categorized as a class
A carcinogen and has established a threshold of what is considered a safe level of exposure.
In the US the level is 4 Pci/L or four Pico curies per liter if air. In Europe it’s only half this
Although health issues resulting from radon (i.e. lung cancer) form a direct link to radon
levels and length of time exposed, there are still many things that are not known about its
contribution to other ailments so why put yourself and family members at potential risk when
testing is easy and affordable; in fact anyone can test their home for radon and if there are
children present I encourage you to do so. Most testing devices have instructions, if not just
ask the suplier or go to my website for “the rest of the story” most test devices cost between
$20. and $30 dollars which includes the cost of the lab analysis, but don’t sit on the sample
tests too long because the radon decay products will diminish quickly giving a bad or no
reading. If you don’t have the time go on the website for the National Environmental Health
Association or NEHA to select a certified radon tester in your area; www.neha-nrpp.org
You can order EPA publications by calling 1-800-490-9198 or by visiting this website
www.epa.gov.ncepihom, or if you need a test kit you can call the lab at UCCS at 719-262-
3584 or PDS supply at 444-0646 for Colorado Springs or call the Hotline at 1-800-sos-radon.
You can also order on line at www.radon.com
View the rest of this article on my website Crescendohomeservices.com
Testing for Radon
Over the years we have heard all the problems associated with lead exposure, asbestos exposure and than came
formaldehyde exposure followed by mold exposure and the large lawsuits that accompanied these environmental
hazards, raising our awareness levels after the fact, or when the settlements got insane, motivating insurers to
demand government intervention and education. Yet the only time we hear about these issues is when we are
handed a disclosure statement during a real estate transaction listing the nasty substances no one likes to dwell on
and it is really up to the consumer or purchasers to prove an existing condition exists. I can’t say for sure if Radon
will follow suit (pardon the pun), but it’s got all the makings as well as now being another itemized hazardous substance on the disclosure list, and now we even have lawyers advertising about it, so why take the chance.
If we are living in a dwelling we should test for our own piece of mind, if we are selling a property we should test
to avoid unexpected costs since many home inspectors now test for it and to avoid potential litigation, if we are
buying a home, again we have it tested if for nothing more than to avoid the possibility of having to shoulder the
costs of a possible mitigation ourselves when it’s time to sell.
To test a dwelling we need to secure testing devices from a lab or hire an independent to do the test, but if you
want to do it yourself here’s what you need to know; there are several different devices on the market but the most
used for short term tests are charcoal canisters, resembling a can of chewing tobacco. It’s always good to document
all pertinent information such as physical address person taking the test, date and time, external factors such as
temperature or barometric readings or what the weather is doing. Heavy winds and heavy rains will cause higher
than average readings as well as heavy snowfall already on the ground so any extreme conditions in the atmosphere
should be logged and reported to the lab doing the test. You must also document the precise location of the testing
device and the time and date it was sealed typically four to seven days after the test began.
The next thing we need to do is to control the environment in which we are testing, for instance; we want to go
about our business as usual but we don’t want to have open windows blowing on the device (which can actually
make readings higher in some instances), and we don’t want to leave doors closed to the area being tested, nor do
we want exterior doors open for any length of time. So in general we want the home to be sealed just not
hermetically sealed (which also can give an elevated reading). We are trying to establish an air exchange ratio that
is close to normal without aggravating the test results. We can leave the furnace on, yet we don’t want to run air conditioning since it pulls its air from outside and we don’t want to test during a heat wave if we’re living in the
home. It’s best not to test if a storm is brewing, or when you’re remodeling, painting, or have given temporary
shelter to the Girl Scout troop.
Next we need to position the device within the established guide lines which are at least 3’ feet from any door or
window, at least 20” inches off the ground and no closer than 4” inches to any object like walls, furniture, plants
etc.. Careful consideration must be made in its placement if you have children or pets; higher up is always a good
The best location for placement is dictated by the type of home or structure being tested. We don’t put testing
devices in crawl spaces unless we are living in there, nor do we put test devices in a cellar or a room considered to
be a basement yet would not make habitation practical save legal. We should be testing in the lowest habitable level.
Now if your testing your own home that has an unfinished basement you need not test the basement unless you plan
on finishing it or you spend a great deal of time there or if you are planning to sell, since it is a general practice by
testers to test in the basement if it has the potential to be added as living space in the future. You can also test both
levels at once.
The best locations for placing test devices are living areas and sleeping areas, not closets, kitchens and baths that
have external fans and high humidity levels; which can distort radon readings.
Once the test is complete get it to the lab ASAP! Time is not on your side because radon decay products don’t stop
decaying, so it’s best to get them to the lab in 24 hours. 48 hours is acceptable but now the lab has more work to do
with estimating the decay differential.
What to do if your lab results come back over the 4Pci/L threshold;
First, don’t panic there are contributing factors to high radon levels and correcting some can help avoid the expense
of mitigation equipment. If the lab results came in showing readings of between 4 and 10 Pci/L we can look at
contributing factors; were tests performed in January during a cold snap and the furnace was running continuously,
or if high winds persisted during the test or even heavy rain or snow? How about that open masonry fireplace, a
bonfire will suck untold amounts of air up the flue, even leaving the flue open is not in your best interest. Doing ten
loads of laundry can contribute to a condition known as negative pressure when the home is exhausting more air
than it’s sucking in. Heating alone can cause the stack effect in any home drawing soil gasses up by means of
natural air convection. But there is one option that is a no brainer if your readings are between 4 and 10, go back to
the lab and get a long term test device. Alpha tracking is a good method for long term (over 90 days) and it gives
one a better overall measurement that is more conducive to an actual living environment while not allowing
weather patterns to discriminate against you. You need not bottle up your home for these tests, just mark on the
calendar months ahead when to take the device back to the lab, otherwise you might forget. If that test still comes in
high, keep reading.
If the test comes in between 10 and 20, you can do another short term test and average the results of both, even in a
best case scenario your reading is probably never going to be below 10 unless one test failed. If the test was taken
in the basement, scope it out! If the device was placed in a room containing a sump pit where perimeter drains tie in,
you have a radon processing system, a virtual speedway for soil gases to enter the home unabated. There are ways
to seal these while still allowing inspections and maintenance.
If you have any openings in your concrete where you can see the soil behind it you need to seal these as well,
plumbing and electrical conduits are typically suspect. If you live above a crawl space check to see if a vapor
barrier is installed, this is usually just plastic sheeting laid over the soil, it’s not the end all but it can help slow
movement in average weather conditions. Does the crawlspace have vents, most do and their usually closed for fear
of bursting pipes and colder floors. Is there enough venting, by modern codes; you need one square foot of venting
for each 150 sq, ft. of floor area, so a 1500 square foot crawl should have 10 sq. ft. of venting.
Some older homes have pathways for the lower air to travel to the upper floors, sometimes straight to an attic
through utility chases; blocking these can not only slow radon but keep fires from spreading too quickly. Older
homes that have older furnaces probably weren’t provided with an air supply allowing combustion make up air for
periods of extended heating which can cause negative pressure situations contributing to elevated radon readings
and occasionally elevated carbon monoxide levels. Having a HVAC company install one can make a difference. If
your ceiling has inadequate insulation less than R-30 you can reduce the stack effect by adding more.
If you’re on a slab on grade your options are minimized raising the potential for mitigation.
If your readings are over 20 doing all of this won’t help enough to make a difference and you should seriously consider mitigation. If you think you may have made a difference, retesting is in your best interest.
If you’re in a new home check to see if the builder provided a passive radon system; if the home is radon ready
mitigation is a snap. When building a new home there is no sound method of pre-testing the open ground. When
you’re building over granite or shale, install a passive system to prepare for the inevitable. For more on new homes
New Homes VS Old Homes
Air quality exposed
It’s been almost twenty years since my first building science course and my OSHA certification lapsed years ago
as well, but in that time the homes haven’t changed that much, just our understanding about how indoor air quality
can become far worse than what’s found outside in our dirtiest cities. When you’re in the remodeling business it’s
important to know the basic health hazards that can be associated with your work, so being forewarned is forearmed,
we don’t want to do more harm than good in any event. Being able to identify asbestos, lead paint, and mold is only the beginning, determining if you can work safely and
cost effectively around these issues can make or break a deal, especially if you mention the words abatement team.
The age of the home is a great indicator of what substances will be found within, and customers must be aware first
hand the possible threats that can be encountered when ripping a wall open or even removing old furnace venting.
Asbestos can be found in old insulation, drywall, plaster, flooring, and pipe coverings as well as acoustical ceilings,
roofing and siding and that’s only a partial list. If a home is in a flood zone there is always potential for mold or if
there was a source for water leaks that went undetected for any length of time, mold can creep, even the inside of a
shower wall can harbor mold.
Years ago I was working for a real estate outfit doing repairs on rentals and accidentally found a homes basement
walls crawling with mold, when I mentioned this to the tenant she said she was aware of it. So I proceeded to tell
her the possible health implications causing her face to lose all expression before becoming pale. She then told me
about her husband’s recent bout with a virus like respiratory ailment that almost took his life. She then put together
the fact that just a few days before he was admitted, he had been working in the mold encrusted room; needless to
say that realtor never called me back to work on any more properties which suited me fine!
When we remodel homes we sometimes change the matrix of a home disturbing its delicate balance in the form of
air change ratio’s and potentially adding to the exposure levels of the homes already present toxins and this is what
got me thinking about the radon problem. Was I creating a sick home while trying to improve upon existing
conditions? I wasn’t sure, but at least now I know what steps to take in order to restore law and order after I’m done.
Whenever the inside envelope is changed on an existing residence I recommend a radon test even if one was done
prior. Remodeling a basement can change things just as much as adding an addition so it’s a good idea to address
the need for combustion air if there’s none present. Insulating the floor cavity in crawl space enables the vents to
remain open provided you don’t position plumbing too close and use a burst resistant material. The homes our
grandfather built were probably a great deal more drafty than today’s homes, and if your granddaddy built it before
WWII don’t expect the walls to be insulated, although I have come across some interesting reading material.
When we weather proof a home or add new windows and doors we sometimes diminish the air quality within the
home by changing the amount of fresh air exchanges. When we remodel interiors we have to be concerned about
off gassing from cabinets, counters, flooring and finishes, when the occupants have allergies and are overly
sensitive to certain products like formaldehyde, benzene and toluene based products. Although off gassing will
decrease in time, it’s best to know what ails thee.
New homes are much tighter, sacrificing air quality for efficiency, yet even when they are well insulated and have
appliances with combustion air don’t write them off as far as radon is concerned because for unknown reasons some soil just produces a great deal more and unsealed sump pits connected to perforated drain tiles can be found in
plenty of new homes providing easy access along with block-outs in the slab to allow for future plumbing
connections. Even if the home were built on solid clay; if we use the wrong type of gravel under the slab or in back
fill areas, we increase the potential for radon.
To make homes radon resistant or radon ready there are a host of things that can be done; we can start by using a
washed gravel under slabs to aid air circulation along with internal perimeter drain tiles connected to a evacuation
point that will eventually vent through the roof. Collector mats available through radon equipment supply centers
are also good candidates for installing around perimeters before the concrete goes in. Exterior basement walls
should be water proofed and external drain tiles installed, this also provides a means for future mitigation
equipment by tapping into external drain tiles. Crawl spaces can have a vapor barrier installed and then a slush coat
of concrete can be leveled over the soil, this is generally 2” of concrete floated but un-troweld, site conditions must
be suitable for this to work and when building in the mountains this is rarely the case. It doesn’t hurt to install an
internal drain tile in the crawl if your going to return fill along the footing areas to provide a usable venting device,
in fact running polly sheeting along the interior wall before backfilling the walls, is a good idea since sealing a
membrane to concrete is difficult if not tricky when your trying to make the crawl space ground cover air tight.
There are provisions and recommendations for dealing with radon in new homes in the 2003 IRC code books for
When we are planning radon measures for a new home we need to add a 3” preferably 4” vent pipe that’s to be
vented through the roof just like a plumbing soil stack, ( PVC pipe is preferred), so a double or 2x6 wall is needed
for routing to the roof, provided its labeled on each level so plumbing is never accidentally attached to it, and it’s
usually a good idea to do this after the HVAC and plumbing is run since these must go in certain locations This is
all that’s needed for a passive system; however a passive system doesn’t always do the trick. If the vent system is
installed where it isn’t accessible a future vacuum pump will not be allowed to be installed if readings are still high,
so it’s best to locate some of the vent pipe through an accessible attic space and provide an outlet or junction box
within five feet of it for a vacuum pump since they can’t be installed within living spaces.
Does this add to the cost of the home? You bet, but how much is your piece of mind worth!