What is mass timber?

Mass timber uses state-of-the-art technology to glue, nail or dowel wood products together in layers. The results are large structural panels, posts and beams. These exceptionally strong and versatile products are known as mass timber.

 

Mass timber product infographic

What is mass timber construction?

Mass timber construction, in contrast to light-frame wood construction, is built using a category of engineered wood products typically made of large, solid wood panels, columns or beams often manufactured off-site for load-bearing wall, floor and roof construction. Mass timber is engineered for high strength ratings like concrete and steel but is significantly lighter in weight. Mass timber products are thick, compressed layers of wood, creating strong, structural load-bearing elements that can be constructed into panelized components. They are typically formed through lamination, fasteners, or adhesives. Mass timber can complement light-frame and hybrid options and is an environmentally friendly substitute for carbon-intensive materials and building systems.

commercial office building, Vancouver
Photo: KK Law

 

Mass timber used in MEC HQ, interior angle

What is tall wood construction?

As technology advances, the definition of what constitutes a tall wood building is evolving and rising in height. Taller wood construction can span all-wood mass timber and light-frame systems beyond six storeys to mass timber-concrete-steel hybrid systems more than 18-storeys and rising.

As a safe, viable alternative to steel and concrete, mass timber construction is increasingly being used in taller buildings beyond six storeys. Canada’s national building code permits 12 stories of mass timber construction, taking into account its strength and fire resistance ratings. This change reflects a rigorous review by the National Building Code committees, as well as experts such as fire safety specialists, structural engineers, architects, scientists, and builders.

Some provinces, such as British Columbia, Ontario, and Quebec have already permitted mass timber structures of up to 12 storeys in advance of these code changes. In B.C., an increasing number of communities qualify as early adopters having met provincial requirements including support from their city council, planning, and fire departments along with land use bylaws permitting tall wood construction. And the City of Vancouver has amended its building bylaws to allow mass timber construction up to 12 storeys for residential and commercial use. In BC, there are currently seven projects in the design phase and five under construction that are over 12 storeys.

Brock Commons Tallwood House, UBC
Photo: Brudder

Brock Commons Tallwood House
MASS TIMBER FOR THE MASSES

B.C. leads the way with mass timber buildings

There are more than 370 buildings in B.C. using mass timber. From public structures to commercial and multi-family residential applications, explore buildings using mass timber in our project gallery.

North Vancouver City Hall
Photo: Martin Tessler

Components and systems of mass timber and taller wood construction

Mass timber products are the building blocks that make taller wood construction possible. Products in the mass timber family include cross-laminated timber (CLT), dowel-laminated timber (DLT), glue-laminated timber (glulam), laminated strand lumber (LSL), laminated veneer lumber (LVL), parallel strand lumber (PSL), and nail-laminated timber (NLT). Mass timber and engineered wood products can be used in an array of applications and are the foundation of taller wood building systems.

Types of mass timber framing systems

There is an ever-evolving number of options and systems when it comes to mass timber. Using various combinations and sizes, mass timber products can serve as beams, columns, floors, roofs and walls considering the directional strength of each wood product. In contrast to conventional concrete and steel systems that tend to follow standard templates, mass timber systems offer the potential for greater flexibility, albeit not without some challenges.

Post-and-beam

Post-and-beam mass timber systems are a popular choice and resemble the common approach used in historic heavy timber buildings of the past. It is a skeletal framework of decking, beams, and posts supported on a foundation. The upright wood members are referred to as posts and the horizontal wood members referred to as beams. The post and beams are connected using mechanical steel fasteners. This system of construction requires no load-bearing walls. Glulam frequently serves as posts and beams. Decking systems can be made of panelized mass timber products such as NLT, CLT or others. The post-and-beam system works well for open plan designs such as offices and commercial buildings.

Mass timber floor and wall systems

In contrast to post-and-beam, designers can take advantage of mass timber panels’ two-way spanning capability. This can include mass timber panels constructed to form a honeycomb structure well-suited to handle both vertical and lateral loads. In these systems, mass timber panels—similar to reinforced concrete and steel—form both floor and wall, with the walls bearing the load of the structure. In some instances, mass timber may form the core of a building, in place of concrete.

Hybrid mass timber systems

Hybrid mass timber systems are a broad category that refers to any combination of wood, steel, concrete and other possible materials and building systems. Capitalizing on the performance and strengths of each building material, hybrid systems offer lots of flexibility. This can include a nearly all-wood solution that combines light-frame wood construction with mass timber panels, where only the foundation is concrete, and the connectors are metal.

BC EMTC guidelines

New guidelines for professional practice for architects and engineers designing tall mass timber buildings

Engineers and Geoscientists BC and the Architectural Institute of British Columbia (AIBC) have published new guidelines to clarify the expectations for professional practice for architects and engineers designing mass timber buildings up to 12 storeys.

WoodWorks BC

Need technical support for your next timber-built project?

For information about the WoodWorks BC initiative click on the button below for their free technical assistance contact page.

Brock Commons Tallwood House under construction
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