Cross Laminated Timber (CLT): A new way to build big with wood
Building houses with wood framing is standard practice in the United States. However, for bigger buildings, steel and concrete are the dominant materials. A new wood technology – cross laminated timber – may soon open up the commercial and industrial building sector to wood building.
Wood is an excellent structural material because it is strong, lightweight, easy to work with, inexpensive and environmentally friendly. So-called “stick-frame” construction, where dimension lumber (2x4’s, 2x6s, etc), are used to create the building’s structure dominates for building houses in this country. However, its use in larger buildings (e.g. above 3 stories) is limited by building codes for structural and fire-resistance reasons. For larger buildings, steel and reinforced concrete are the dominant structural materials. However, a new technology originating from Europe could change this dependence on non-renewable resources for larger buildings.
Cross laminated timber (CLT) refers to large panels that are created by laminating dimensional lumber. The panels can be very large – 50 feet long, 10 feet high and a foot thick or larger – depending on the structure requirements. Because they are very thick, they have the excellent fire properties of large timbers. And, because they cross-laminated like plywood, they are very stable. Finally, because they are manufactured in a factory, quality control is very high and prefabricated panels can be easily and rapidly put together on the building site. For example, for a CLT building in Britain, a four-person crew was able to assemble an entire floor of the nine-storey building in just three days.
Cross-lamintated panels can be used to create very large and structurally-sound buildings. A seven-storey CLT structure that was tested for earthquake resistance suffered no damage. CLT is now being manufactured and used in Europe. There are now four producers in North American and perhaps more on the way, as builders, wood products manufacturers and building code officials learn more about this exciting new option.
Building with wood is good because it allows us to use an affordable and renewable material for one of out most important needs. CLT may new allow us to build even more things with wood.
For more information, contact Adam Taylor at 865-946-1125 or AdamTaylor@utk.edu .