As we continue to burn through our nonrenewable resources at an alarming rate, it is important that we never underestimate what we can do with our resources that can be replenished. One of these, wood, is an extremely valuable material but has been underutilized in construction for one big reason: fires. Every so often, a wood structure like the 188-unit apartment complex in Richmond, BC, burned down in 2010 goes up in a blaze and hinders the support of timber construction in a big way. While this is a valid concern, there are several things to consider before abandoning hope. Most of the big building fires covered by the news have been on uncompleted buildings still under construction. This means that fire suppression systems haven’t been installed yet, and oftentimes incomplete floors lacking fire-retardant drywall, or walls of any kind, give the fire huge ventilated areas to spread. This is hardly fair to mark these fires as a failure of wooden construction. In completed buildings, close to 80 percent of fires are contained to the rooms they are started in.
Furthermore, fire damage isn’t limited to wooden buildings. Structures made of concrete, steel or other construction materials can still weaken and collapse under the heat of a fire. In fact, heavy timber resists fire very well, burning slowly and creating a layer of char that helps to preserve the structural integrity of the inside wood.A recent advancement in timber technology to note is Cross-Laminate Timber, or CLT. CLT is made from stacks of industrially dried and fully glue-coated lumber. It is exceptionally strong, multi-purpose and lightweight. Construction using CLT is quick because it is easy to prefabricate and transport. Like heavy timber, CLT produces a layer of char when burned, and when used in construction, engineers factor in this layer and use enough wood to allow charring to form while still maintaining enough internal wood to be structurally sound. Also cosmetically, CLT looks pleasing and can be left exposed, reducing building cost. CLT has been considered the future of wood-based construction and for good reason.
So with some of the negative stigma of wooden construction debunked and the values of timber buildings explained, this leaves the biggest value of it all to think about: renewability. Timber is the only 100% renewable material for building construction. One billion cubic meters of logs are produced each year in North America and Europe alone, creating 200 million cubic meters of engineered timber and done in a careful way so that forests maintain their size. This is enough material to build 150,000 offices a year. Timber also locks up carbon that was absorbed by the tree during its growth, reducing pollution. As we look to the future, we should look to the trees. It’s time for timber construction.
NASF May 15, 2015 E-Newsletter, National Association of State Foresters
Making the Case for Wood Construction, Treehugger
Timber Offices: The Time Has Come, ARUP
The Education Store, Purdue Extension Resource Center (search “timber”)
What is Cross Laminated Timber? American Wood Council
2014 Indiana Forest Products Price Report and Trend Analysis, Indiana Department of Natural Resources