Hoping to develop a non-destructive and less expensive method than is
now available to detect mold behind walls, Georgia
Tech Research Institute (GTRI) scientists are collaborating with humidity
control expert Lew Harriman of Mason-Grant
Consulting in a two-year feasibility study primarily funded by the
U.S. Department of Housing and Urban Development
(HUD) through its Healthy
Homes Initiative. The Air-Conditioning
and Refrigeration Technology Institute in Washington, D.C., and Munters
Corporation in Norcross, Ga., are also providing funds for the study.
"Mold is a common problem, especially in humid, southern climates,
but people are often not aware of it because it's occurring behind a painted
or wallpapered wall," said GTRI research scientist Victor DeJesus.
"Then it's too late when they realize it. The wallboard must be replaced."
In addition to degrading structures, mold can emit smelly and potentially
harmful compounds into the air, DeJesus added.
Researchers are conducting experiments on damp, mold-infested wallboard
panels. Initially, they are using a signal processing algorithm and high-sensitivity,
laboratory-size radar system recently developed by GTRI principal research
scientist Gene Greneker and senior research scientist Otto Rausch.
They will determine the feasibility of using millimeter-wave, extremely
high-resolution radar to detect mold in these panels based on unique characteristics
of the mold backscatter signature, extracted by unique signal processing
techniques. Also, Harriman will investigate the possibility that X-ray
and gamma-ray technologies might work. And later, the researchers will
examine the effectiveness of these techniques in detecting mold in other
indoor building materials, including ceiling tiles typically used in commercial
Ultimately, the researchers hope to produce a small, handheld prototype
unit - something akin to a stud finder - to lay the technical foundation
for a commercial product that contractors could purchase for about $1,000
to $2,000 and easily learn to use. They would then test that prototype
in actual houses.
Radar expert Greneker envisions a system that would map mold behind a
wall. If dampness is indicated by the radar-based device, then a contractor
could know more precisely where to probe for damage, he explained.
"We think this technology is on the cutting edge for detecting mold
behind walls," Greneker said. "Its potential is immense."
In an initial experiment that began in January 2004, researchers used
a small panel of wallboard -- which is very porous -- soaked in water
and injected with non-toxic fungal spores. In one month's time, those
spores germinated as the wallboard was kept in a high-humidity environment.
Mold thrives in damp wallboard because of its paper-based encasing, DeJesus
Researchers then used the radar system to scan the wallboard panel, and
they were encouraged by the early results. Now, they are tweaking the
algorithm to enable the radar system to discriminate between the mold
backscatter signature and nails, boards and wiring that would be found
in and behind wallboard, Greneker said. They must also find ways to reduce
the system's cost, while retaining its sensitivity, he added.
This experiment and a larger-scale one that began this spring simulate
what might happen to wallboard dampened by a home's leaking pipe or roof,
or from condensation formed by a HVAC system, or even from high-humidity
conditions, DeJesus said.
If left unattended, mold can destroy structures and cause serious health
problems. The researchers cite a well-known case in which a jury awarded
$32 million in damages to plaintiffs in Texas who sued over a neurological
condition and asthma their doctors attributed to mold in the home they
In less serious cases, the consequences can still entail a lengthy and costly repair process, the researchers say. A contractor must pinpoint the damaged area by drilling holes in the wall. Rotting wallboard, insulation and, perhaps, studs must be removed, the area dried and then decontaminated before new wallboard can be installed.
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