As with any structural material, perhaps the most important single factor to a long and useful service life is effective design. Extensive research and documented experience have led to a number of proven strategies for ensuring that wood material reaches its full potential for longevity. This course outlines the informed design, specification, detailing, and quality control during construction, installation, and maintenance that are collectively key to achieving maximum durability in today's wood construction.

Durability and Sustainability

Durability is a key component of sustainability. Before making a large investment in a building, it is important to consider its environmental impacts versus realistic lifespan. For example, it has been suggested that concrete should be used for buildings because it can last 100 years. However, research indicates that there is actually no significant relationship between the material used for a building's structural system and its service life. Rather, a study of buildings demolished between 2000 and 2003 in the Minneapolis/St. Paul area found that most were demolished because of changing land values, changing tastes and needs, and lack of maintenance of non-structural components.² Only eight buildings (3.5 percent) were demolished because of structural failure. In fact, wood buildings in the study were typically the oldest; the majority were older than 75 years. In contrast, more than half the concrete buildings fell into the 26- to 50-year category, with only a third lasting more than half a century. Some 80 percent of the steel buildings demolished were less than 50 years old, and half were less than 25.

The Fulton County Stadium in Atlanta was imploded in 1997, just 32 years after it was built and shortly after it had been refurbished to host baseball events for the 1996 Olympics. The concrete in the older building was intact–in fact, demolition was costly and complex. But the needs of the community had changed, a shift that would have been difficult to predict when the structure was built. Photo courtesy of DH Griffin Companies

Overall, the fact that wood buildings had the longest lifespans shows that wood structural systems are fully capable of meeting a building's longevity expectations; however, considering the embodied energy in demolished buildings and the implications of material disposal, the fact that wood is adaptable either through renovation or deconstruction and reuse is a significant advantage.

When the Forté was completed in 2012, it was the world's tallest residential wood building. Photo courtesy of Lend Lease (developer)

Many architects believe wood can add to a building's longevity, and thus sustainability, not only because of its physical properties but because wood buildings tend to be valuable to their occupants for reasons related to aesthetics, comfort, acoustics, and innate positive human response to wood. Marc L'Italien, whose architecture firm EHDD often uses wood materials on its projects, puts it this way: “Whenever we can, we select materials with integral finish, both from a sustainability angle and because there is inherent beauty in well-detailed natural materials. This is one of the most overlooked aspects of sustainability. It's not about the points. It's about designing places where people want to be. The more they like their environments, the less likely these structures are to be demolished. A strong following and internal flexibility allow them to be repurposed when the users and owners change over time.”