Construction Defects
Atlanta Homes Built with Radioactive Concrete
Brendan Keefe | WXIA
May 6, 2015
An entire condo building in metro Atlanta was built with radioactive concrete, according to an inspection report obtained by the 11Alive Investigators. It's a relatively new phenomenon where radon inspectors and remediation companies are finding the gas emanating not just from the soil but also from building materials.
Radon is an invisible, odorless, radioactive gas that claims more than 20,000 lives a year, according to Environmental Protection Agency. As radioactive particles decay in the lungs, they can cause lung cancer. The EPA estimates 7,000 of the people who die from radon-induced lung cancer are non-smokers. In fact it's considered the number one cause of lung cancer in non-smokers.
"Your entire life, you're accumulating a dose exposure," said Matt Koch with Southern Radon Reduction. Casual exposure isn't a problem, but living with elevated levels of radon in your home for years can be deadly.
The source of radon is almost always traced to the soil beneath a home. Radon is gas comes from radium ore, which is produced by the decay of natural uranium in the ground. North Georgia is considered a hot spot for radon, and experts say about one in five Metro Atlanta homes has radon levels above the EPA action level.
The EPA recommends that homes have radon levels below four pico-curies per liter – about 10 times the amount naturally in the outdoor air.
Concrete is made using crushed rock, and that is usually obtained from local quarries, rather than those far from a construction site. As a result, concrete used to build Metro Atlanta homes contains some of the same radioactive rock that produces radon in the soil.
Is there enough radioactive rock in local concrete to cause unhealthful levels of radon in homes? Sometimes the answer is yes, according to Matt Koch, the Atlanta radon expert who is developing new remediation techniques for radon in building materials. "High concentrations of radon from emanation was not really something considered in houses here in Georgia," Koch said.
Tell that to homeowner Roger Grabman. After half a dozen holes were drilled into his foundation to vent the soil, the radon level barely dropped. "We put in one hole, we put it another hole, we put it the right number of holes and it still didn't fix the problem," Grabman said.
Matt Koch was the remediation contractor. He was determined to find a solution. "No matter what we did, the radon level didn't go down," Koch said. Grabman, himself an engineer, concluded, "It was indeed coming from the materials inside the foundation."
Tests confirmed that hypothesis. While the 11 Alive Investigators were in Grabman's basement, Koch used a device to measure radon levels in the basement air long after he sealed the concrete walls with an industrial plastic. It came back at just one pico-curie per liter – well below the EPA limit. But when he put the device behind the laminate on the concrete wall, it hit 578 pico-curies of radon.
"That's more than a thousand times the amount of radon you would find outside," Koch said.
A few years back there were concerns over granite countertops emitting radon from naturally-occurring radioactive material in the rock, but the EPA determined there simply wasn't enough radon coming from kitchen countertops to elevate levels in the home. The difference with concrete is that there's often a lot more in the home, with a lot more surface area for the gas to enter into the surrounding air.
That's what happened at a nearly 300 unit condo tower in Metro Atlanta. It was built primarily using poured concrete.
An out of state buyer demanded a radon test for her unit, even though it was on the fifth floor of the seven story tower. The home inspector relented, expecting to find nothing, according to Koch. The test came back at 10 pico-curies per liter, "two and a half times the EP action level," Koch said. "A fifth floor unit shouldn't have a radon level of 10. They tested it again, sure enough it came back at 10," he added.
The condo owners brought in several radon companies to test levels and determine the source. An inspection report obtained by The 11Alive Investigators shows high levels of radon throughout the condo tower, with inspectors isolating the concrete as the source.
The problem wasn't just the concrete, but modern construction methods and building codes designed for energy efficiency. "These condos were very, very tight, very energy efficient, so the radon couldn't get out," Koch said.
Sealing the radon behind a vapor barrier was not an option in the condo tower because the concrete floors, ceilings, and walls were not exposed inside the nearly 300 finished units.
The solution was simple: add fresh air.
Koch said every unit got an air exchanger, immediately lowering the radon levels below the EPA action level. "Even very small incremental changes in the tightness of the building envelope can make huge magnitude of difference in radon level," he added.
Condo management declined our request for an interview. After hanging up on our first call, the manager emailed "no comment."
Koch has found radon emanating from a handful of residential basements throughout Metro Atlanta, but he says it's still the exception, not the rule. The soil is still the primary source of radon in most homes he treats.
So how do you know if the invisible gas is at elevated levels in your home? Test.
Home improvement stores sell retail tests. The University of Georgia Cooperative Extension Office sells home test kits for eight dollars. Most real estate inspectors can perform the test, and there are several remediation companies in North Georgia. They charge between $1,500 and $2,500 to vent the soil if you have high levels of radon. The National Radon Proficiency program offers a directory of approved radon remediation companies. Not all of them know about building emanation because it's a relatively new phenomenon.
Matt Koch's Southern Radon Reduction is experimenting with several techniques for sealing concrete, including specialized laminate plastics and epoxy paints. There's also the option of adding fresh air at the expense of energy efficiency.
Do you have radon in your home? "The only way to know is to test," he said.
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SOURCE: www.11alive.com