Research Emphasis Areas

Project Leader:
Clausen, Carol A.

Research Emphasis Area: 
 Advanced Structures

Overview:
Wood structures need to be properly designed to minimize wetting of building components to reduce the risk of biodeterioration. Wood products specifications have often not kept pace with changes in building design, such as the use of new composite and engineered wood products as well as the introduction of non-wood building products, which have changed how building components interact in service, especially in regard to their response to moisture.

Replacement of decayed wood resulting from moisture damage to homes is responsible for an estimated 10% of the annual timber cut in the United States. Our research aims to minimize the potential for moisture damage to structures while maintaining or improving the energy efficiency of the building and the indoor air quality for the occupants.

Researchers are studying the wetting and drying behavior of building components and how rain-water penetration and air leakage into a structure affect its durability. New test methods are being developed to measure the corrosion of fasteners, particularly those associated with preservative-treated building products, to improve the durability of wood-fastener connections.

The sustainability and health of America's forests depends on the efficient use of our timber resources. Research on improved building design helps conserve the wood resource by increasing the durability and service life of wood and wood products, thereby lessening the need for replacement and repair.

Project Leader:
Clausen, Carol A.

Research Emphasis Area: 
 Advanced Structures

Overview:
Protection of wood structures from fire is one of the most critical safety issues facing our country. Our research in this area focuses both on increasing the survival of homes and structures located in the wildland-urban interface that are threatened by forest fires, as well as studying the behavior of engineered wood products used in construction when subjected to fire.

Our research is aimed at improving our understanding of the fundamental multi-scale physical processes that govern fire behavior. Our findings will allow us to develop predictive models to estimate the in-service behavior and performance of wood products, and aid in the development of technologies to improve the survivability of wood structures subjected to wildfires. Evaluation of exterior decking, siding, and roofing materials will be useful in creating guidelines for homeowners concerning the use of these products.

The increased use of engineered wood products in construction provides many benefits, including efficient structural performance, improved wood utilization, and reduction in hazardous fuels in our Nation's forests; however not enough is currently known about their performance in severe fires. Our research outcomes will result in the creation of a database to support the establishment of performance standards for engineered wood products, such as trusses, I-joists, and composite lumber products, increasing the safety of their use.

Project Leader:
Clausen, Carol A.

Research Emphasis Area: 
 Advanced Structures

Overview:
Almost 400 million cubic feet of preservative-treated wood is produced and consumed in the United States annually. However, more environmentally compatible preservatives are needed to replace conventional biocides currently in use.

The voluntary withdrawal of chromated copper arsenate (CCA) from residential applications in 2004 was a historic change for wood preservation, and other preservative systems may soon face similar environmental scrutiny. Our researchers are developing new, environmentally preferable wood preservation technologies, including heavy-metal- free formulations. We are also studying methods for reducing the levels of preservatives needed for effectiveness and evaluating the natural durability of some species as an alternative to treated wood in appropriate applications.

Researchers are assessing the environmental impact of existing preservative treatments to ensure that treated wood can be safely disposed of and does not adversely affect water quality. Studies include investigating the leaching of preservatives from treated wood into the surrounding environment and identifying current treatment practices or exploring alternative treatment methods that reduce leaching.

Although these changes in wood preservation are needed, it is difficult for researchers to respond quickly to societal pressure for environmentally compatible preservatives because it takes many years to evaluate the long-term effectiveness of new preservatives. Our researchers are working to develop improved accelerated test methods to more rapidly assess the potential for a wood preservative to provide long-term protection, and reduce the time needed for the development and acceptance of new environmentally preferable preservatives.

Project Leader:
Clausen, Carol A.

Research Emphasis Area: 
 Advanced Structures

Overview:
Chemicals used to protect wood from deterioration by fungi and insects have generally been broad-spectrum biocides that are facing increasing environmental regulatory pressure. Our researchers are taking a new approach to wood preservation that focuses on developing selective biocides that protect against specific threats to wood. Developing targeted preservative systems offers a way to control wood-degrading organisms in an environmentally responsible manner.

With this approach, researchers study the mechanisms by which a particular fungus or insect is able to degrade wood, enabling them to develop an inhibitor based on that particular mechanism. Researchers also study how specific organisms tolerate various wood preservatives and use that knowledge to design preservative systems that neutralize, block, prevent, or counteract that tolerance.