Homebuilders’ drywall study draws criticism

A homebuilders trade group released corrosive drywall guidelines Wednesday that differ from the federal government’s, leading some critics to question the latest study’s scientific soundness.

The National Association of Home Builders’ 82-page document outlines its recommended process for builders to test and repair homes built with the drywall. The study is based on more than a year of research, officials said during a teleconference call with reporters.

“This is a new resource for builders and remodelers to answer critical questions ... in a landscape cluttered with untested products, devices and procedures purported to resolve drywall problems,” said Barry Rutenberg, the NAHB’s first vice chairman and a Gainesville builder.

The drywall, much of it imported from China during the 2004-06 housing boom, has been blamed for emitting noxious sulfuric gasses that corrode air-conditioning coils and other metal components, and cause health problems such as runny noses and watery eyes. Florida has been the drywall saga’s epicenter, with thousands of homeowners registering complaints with state and federal health and safety officials.

The builders’ protocol was developed by risk analytics firm Marsh Risk Consulting and Rockville, Md.-based Building Health Sciences The builders’ protocol was developed by risk analytics firm Marsh Risk Consulting and Rockville, Md.-based Building Health Sciences Inc.

While the study’s authors said they reviewed federal research, several of their conclusions are based on testing done by Knauf Plasterboard Tianjin Ltd. -- a Chinese drywall manufacturer.

That has some critics panning the builders’ guidelines.

“Basically, it’s a whitewash,” said Mike Foreman, a Sarasota construction consultant who advocates a drywall-remediation method he helped develop. “It’s a problem and they’re looking to limit their exposure. They’re looking to get test results they want or test results that don’t tell them anything.”

The builders’ protocol first calls for verifying whether there is any problematic drywall. If there is, builders should take baseline measurements, enter a memorandum of understanding with the homeowners on how the home will be fixed, then temporarily relocate the homeowner and personal items so the home can be remediated.

Once the suspect drywall is removed, a thorough cleaning should be done as many times as needed to remove all traces of it, the study said. Once follow-up testing confirms no drywall traces remain, builders should install new drywall and return the home to its original condition so the homeowner can move back in.

That generally follows the framework spelled out in guidelines issued by the federal government and a federal judge who is overseeing a consolidated drywall court proceeding. But the builders’ study differs in several key areas.

For example, federal guidelines recommend removing and replacing all electrical wiring until further research is done. The builders recommend replacing all low-voltage wiring -- such as in alarm systems and garage-door controls -- and only the corroded portions of high-voltage wiring.

The study’s authors recommended builders “pay close attention” for updated results from federal studies into the drywall’s long-term corrosion of electrical wiring and fire-safety components. Those results are expected soon, agency spokesman Scott Wolfson said.

Also, federal testing has identified hydrogen sulfide as the most likely source of the odors that homeowners complain about. But the NAHB study barely mentions it, instead concluding that other sulfuric compounds called organosulfides -- such as butyl ethyl sulfide and propanethiol -- also are culprits.

“It should also be noted, however, that the characteristic, rotten-egg odor of hydrogen sulfide is not noticeable in problematic drywall homes,” the study said. “Rather, corrosive drywall odor appears more consistent with a mixture of organosulfides.”

Gary Rosen, a Davie environmental/construction consultant who also has been investigating the drywall and has developed a different remediation method, contends the builders’ guidelines actually go too far in some areas and that only will drive up costs. He also questioned the report’s scientific merits.

“Where’s the facts? Where’s the data? Otherwise it is just opinion and b.s.,” Rosen wrote in an e-mail to the Herald.

Dr. Barbara Manis, Building Health Sciences’ chief medical officer, defended the report’s findings and recommendations as scientifically sound.

“We know this methodology works and can be confirmed,” she said.