Misperceptions still exist that buildings made of materials such as concrete or steel last longer than buildings made of wood. As with any structural material, the most important factor to a long and useful service life is effective design. Extensive research and experience have led to a number of proven strategies for ensuring that wood material reaches its full potential for longevity.
The best environmental choice is to use construction materials that are durable enough to last the lifetime of the structure and can be reused or recycled once its useful life has ended. In North America, this is usually about 50 years for a non-residential building, which means it is better to design buildings that can be easily adapted to new uses or deconstructed so materials can be reused or recycled.
Regardless of material, long-term durability starts with good design—including proper detailing, product selection and quality control. Also, advanced planning to protect wood during construction can contribute to long-term durability.
Several British Columbia wood species are naturally termite-resistant, including western red cedar, yellow-cedar and a number of hardwoods. Douglas-fir is moderately resistant and for other species, applying a treatment such as borate provides additional resistance against termites.
Western red cedar and yellow cedar is ideal for outdoor applications because they are naturally resistant to rot, decay and insect attacks.
Wood is naturally capable of absorbing and releasing moisture, and handles high humidity without compromising its structural integrity. It delivers excellent performance in the wettest climates, from Asia to the southern US and high-humidity applications, such as aquatic centres. Plus, wood is a natural humidity regulator: its moisture content always matches the ambient air, providing natural humidity stabilization and regulation.
With proper detailing to prevent bulk water intrusion and moisture entrapment, issues such as decay and mold can be avoided. Simple construction details, such as ensuring that materials are compatible and leaving gaps between sheathing panels and between floors in cladding, will accommodate shrinkage and swelling.
Moisture management can be achieved by best-practice design details that protect wood-frame buildings and envelope assemblies against decay, using four lines of defense: deflection, drainage, drying and durable materials.