Each year, replacing deteriorated wood in U.S. homes costs billions of dollars, but research at Mississippi State University is helping protect homeowners’ wallets and the environment.
"Since 1988, scientists in the Forest and Wildlife Research Center have been studying the development of totally organic biocides," said Tor Schultz, MSU forest products professor.
In the past, wood preservative formulations contained copper and other heavy metals. However, environmental risks of the disposal of wood treated with heavy metals have required the development of newer, environmentally benign wood preservatives.
"We have developed formulations that increase the efficiency of the organic biocide mixture and lower the cost," Schultz said. "The nonbiocidal additives that we have used are so safe they are also used as approved food additives."
The research has garnered Schultz and colleague Darrel Nicholas three patents.
"We are conducting both ground-contact and above-ground testing of the products," Schultz added.
To speed the process along, new procedures and equipment have been developed to cut in half the time it takes to determine if newly developed wood preservatives effectively prevent decay. These new processes will replace methods developed in the 1950s that can take eight to 10 years to complete.
"Our new test procedures simulate the outdoors," Nicholas said. "The procedure involves the addition of water in soil tubes to simulate the below-ground laboratory testing, or a new method for outdoor field tests. For above-ground simulation, we employ a humidity- and moisture-enriched laboratory."
Speeding the testing period is critical because of increased governmental restrictions on the use of copper products.
"Our goal is to develop wood preservatives that are both environmentally friendly and effective at preventing wood decay," Nicholas said. "Long-standing methods of visual inspection to determine decay have proven ineffective in spotting early decay."
The new equipment tests the mechanical properties of wood, including flexibility, changes in compression strength and torsion strength.
"Changes in these properties have proven excellent measures of the extent to which fungi is causing early decay," Nicholas said.
In addition to being more effective, the compression strength test reduces from 14 weeks to six weeks the time needed for laboratory decay tests.
Forest products scientists are also testing the use of near-infrared spectroscopy to determine how soon decay can be detected, as well as the extent of the decay.
"Homeowners spend $5 billion annually replacing deteriorated wood," Schultz said. "If we can develop nondestructive test methods to measure the loss of mass and compression strength without harming the wood product, we can save homeowners time and replacement cost."