Cross-laminated timber adds stability to buildings and reduces waste

CLT slabs are difficult to ignite in a fire, remain stable in an earthquake and allow buildings to be constructed faster

Spotted: The hottest new sustainable building material is actually an age-old building material – wood. Wood fell out of favour as a building material in the U.S., especially for constructing larger buildings, after disasters like the Chicago Fire of 1871. It was supplanted by steel and concrete construction instead. However, a method called cross-laminated timber (CLT) has been catching the eye of architects around the world. 

To create CLT, lumber boards are glued together in layers, with the grain of each layer facing against the grain of the layer adjacent. The method is used to create slabs up to a foot thick, 18-feet-long and 98-feet-wide. These wood slabs can actually match or exceed the performance of concrete and steel, are very hard to ignite in a fire, remain stable in an earthquake, allow buildings to be constructed faster, and result in lower costs and less waste. 

CLT was developed in the early 1990s in Austria and has been used extensively in Europe. However, it was slow to catch on in the US until recently, when CLT was incorporated into International Building Code. Since 2015, real-estate developers like Anyeley Hallová and architects like Thomas Robinson of Lever Architecture have been incorporating CLT in an increasingly wide range of projects. Hallová Lever worked together to design a 60-unit high-rise building in Portland, Framework, and demonstrate the possibilities of constructing multi-story buildings out of wood. 

Wood construction with CLT is also more sustainable than concrete and steel. The construction of CLT uses less carbon than concrete and steel manufacture and the wood traps some carbon—instead of releasing it into the atmosphere. In addition, buying sustainably grown wood contributes to healthily managed forests and supports local economies. Robinson points out that, “People get really excited about solar power but may not be focused on the materials the homes are made of, or the energy used while creating and transporting them.” 

There is new excitement from architects around the world over the possibilities of wood construction. In addition to the practical benefits mentioned here, wood is seen to be aesthetically, and even spiritually, pleasing. This has spurred recent innovations such as a 278-foot building constructed entirely of wood and a wooden satellite. 

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