Researchers at the University of Maine’s AEWC Advanced Structures and Composites Center recently were issued a patent for technology that could change the way we build homes and other structures, while cutting the economic losses caused by natural disasters.
The invention is an improvement to Oriented Strand Board (OSB) that’s used in the majority of single family homes in North America, as well as a significant portion of multi-family, commercial and industrial facilities. Primarily it’s used as sheathing for roofs, walls and floors, but the existing material does have some drawbacks.
While OSB has become the dominant wood-based sheathing material used in construction over the last 20 years, displacing plywood, the OSB has certain disadvantages, such as high vulnerability to thickness swelling and water absorption.
The new technology increases OSB’s resistance to high winds and earthquakes, but also contains a coating which both hinders water uptake and prevents the boards from swelling.
UMaine wood sciences and technology professors Douglas Gardner and Stephen Shaler are the lead inventors on the patent. Post doctoral research associates Ciprian Pirvu, Lech Muszynski and Jungil Son also worked at AEWC when the initial work for the patent was done from 2001 to 2003.
In their patent documents, the inventors note that the economic losses from natural disasters in the United States have averaged about $1 billion per week in recent years.
Roof sheathing often flies off in the turbulent hurricane winds, and the problem often has been attributed to improper fastening of the sheathing to the framing, many times causing the entire roof to fail. Without the protection of a roof, water damage often follows.
One potential application for the multifunctional OSB panel would be to eliminate the problem of roof shingle “telegraphing” in roof systems. This occurs when conventional OSB panels experience edge swell under shingles in a roof system and the outline of the panels can be seen on the roof of the building.
“This is an aesthetic problem that might benefit from our technology,” says Gardner.
Surveys also show that a significant portion of the damage resulting from hurricanes or earthquakes occurs in nonstructural parts of the home because of the movement of the structure. The cost to repair nonstructural damage often makes it necessary to rebuild the structure rather than to repair it.
While there are building codes in place to minimize the damage from natural disasters, regulations often are misunderstood and enforcing compliance is difficult because it’s not easy to inspect for these internal building practices.
UMaine’s technology reduces edge swelling of the OSB while simultaneously improving its ability to stay fastened in place when installed properly.