Changes to building codes, combined with advances in wood science and building technology, have expanded the options for wood construction.
Safety and code acceptance:
Today’s building codes recognize the safety and structural performance capabilities of wood, allowing it to be used in a wide range of low- to mid-rise residential and non-residential building types. This includes multi-family, educational, commercial, industrial, retail, public, recreational and institutional buildings.
Building codes require all building systems to perform to the same level of safety, regardless of material used. Wood-frame construction has a proven safety and performance record for fire protection, and the addition of sprinkler systems, fire resistance rated wall and floor/ceiling assemblies, and open spaces around the building, can be used to increase the allowable size of wood-frame structures. Heavy timbers have a particular advantage in a fire because they char on the outside while retaining strength, slowing combustion and thus allowing time to evacuate the building.
Years of research and building code development have proven that wood-frame and hybrid structures can meet or exceed the most demanding earthquake design requirements. In fact, wood’s low mass and high flexibility make wood-frame buildings more resistant to earthquake damage than concrete or steel-framed buildings. Forces in an earthquake are proportional to the structure’s weight and wood is substantially lighter than steel or concrete. Wood buildings also tend to have numerous nail connections, which means they have more load paths so there’s less chance the structure will collapse should some connections fail.
Wood has inherent characteristics that make it ideal in areas prone to high wind. First, its elastic limit and ultimate strength are higher when loads are applied for a short time, which tends to be the case in high winds. When structural panels such as plywood or oriented strand board (OSB) are properly attached to lumber framing, they also form some of the most solid and stable roof, floor and wall systems available. When used to form diaphragms and shear walls, they are exceptional at resisting high winds.
Building codes recognize wood’s structural performance capabilities in a broad range of applications, from the light-duty repetitive framing common in small structures to the larger and heavier framing systems used to build arenas, schools and other large buildings. Engineered wood products offer exceptional stability and strength, and have made wood a viable alternative to steel in many applications where long spans and tall walls are required.