News & Insights

Mass timber construction is having a moment, and it is more than just a trend. While many in the industry have heard the term, few understand why developers, architects, and engineers are seriously considering it for their projects. At a time when the built environment is under pressure to reduce carbon emissions, mass timber is emerging as a solution that combines the strength of concrete and steel with the climate benefits of a renewable, low carbon material.

Beyond sustainability, mass timber construction offers efficiency, aesthetic appeal, and growing code provisions. It’s not the right solution for every project, but when it fits, the impact can be substantial.

The rising popularity of mass timber usage

Mass timber’s growing prominence in North America stems from two major drivers: increasing concern about climate change and construction’s environmental impact, and significant industry advocacy. Both have successfully influenced building codes. In Canada, the US, and European countries, abundant forest resources make this material readily available. Timber is a renewable resource that generates fewer greenhouse gases during production than traditional building materials like concrete and steel.

Building codes have dramatically shifted in recent years to accommodate taller mass timber structures. For example, the International Building Code (IBC) in the United States and the National Building Code of Canada have expanded height limits for mass timber buildings. Where building height limits were originally around six stories, some jurisdictions now permit fully mass timber-framed structures of up to 18 stories. This regulatory evolution reflects growing confidence in mass timber’s performance and safety characteristics, opening new possibilities for architects and engineers.

The aesthetic qualities of exposed wood elements have further fueled interest among architects and building owners seeking distinctive interior spaces. Wood creates warm, natural environments, contributing to occupant wellbeing while showcasing structural elements as design features. While traditional heavy timber construction can provide some of these benefits, it cannot match the design flexibility, structural performance, and sustainability of mass timber.

However, implementing mass timber successfully requires balancing these benefits against practical considerations, including appropriate applications, structural requirements, and long-term performance.

Sustainable advantages of mass timber construction

Mass timber offers significant sustainability advantages over traditional building materials. Here are a few of the most important:

Environmental benefits

As a renewable resource, mass timber stores carbon during its growth phase,maintaining this carbon storage throughout the building’s lifespan. This carbon storage, combined with the lower energy requirements for harvesting and processing compared to steel or concrete material extraction and manufacturing, can contribute to a significantly reduced carbon footprint for mass timber structures

The material’s lighter weight provides cascading sustainability benefits. A mass timber building typically weighs less than a comparable concrete structure, allowing for smaller foundations that require less material. This weight efficiency also reduces transportation emissions, although this benefit can be offset by long trucking distances between forests and some U.S. projects.. At a building’s end-of-life, properly sourced timber can be disassembled and reused, further extending its environmental benefits.

Additionally, compatibility with green building rating systems makes mass timber attractive for projects seeking certification. The material works well with LEED, Living Building Challenge (LBC), and WELL prerequisites and complies with the increasing number of U.S. state and local jurisdictions that require embodied carbon reductions for materials in new public-funded building projects.

Optimal applications

Mass timber is well-suited for low to mid-rise buildings. Its relatively light weight, ease of construction, and thermal performance make it ideal for multifamily housing where speed of assembly can reduce project timelines and construction loan carrying costs.

Educational facilities, including universities and schools, represent another strong application area. Exposed mass timber elements create welcoming learning environments while demonstrating sustainable building practices.

For high-rise applications, seismic design requirements and the current maximum strengths of mass timber shear walls can limit building height. Hybrid systems incorporating concrete cores or steel elements can extend these limits, so most large mass timber buildings are hybrid designs.

One innovative application currently under construction is a circular gathering structure (powwow) for the Muscowpetung Saulteaux Nation in Saskatchewan. The circular design leverages mass timber’s natural flexibility and high strength-to-weight ratio. The exposed mass timber elements also offer aesthetic and cultural significance appropriate for this community space.

Structural performance

Cross-laminated timber (CLT) and glue-laminated timber (glulam) form the backbone of mass timber construction. These provide structural elements with performance characteristics comparable to traditional materials in appropriate applications. The high strength-to-weight ratio of these engineered wood products enables efficient structural designs that reduce material usage while maintaining integrity.

Fire performance, often cited as a concern with wood construction, is addressed through mass timber’s inherent properties. When exposed to fire, large mass timber elements form a protective char layer that insulates the interior wood, allowing the structure to maintain its load-bearing capacity long enough for building evacuation. While the charred portions are unusable after a major fire event, the core structural integrity can be maintained through proper sizing.

Construction advantages

Mass timber construction offers several advantages over traditional methods. The building elements are prefabricated, providing precision and allowing the building superstructure to be manufactured while the foundation is constructed. Components arrive ready for assembly, which means rapid on-site construction with smaller crews and less equipment. This efficiency can translate to faster project completion and earlier occupancy. Potential schedule advantages amount to weeks or months compared to conventional construction methods. This prefabrication approach also minimizes construction waste and improves quality control.

The reduced weight of mass timber components simplifies transportation and handling, often requiring smaller cranes and reducing site impact from concrete trucks and welding. Mass timber construction sites tend to be quieter with less dust and debris than concrete or steel construction, creating better conditions for workers and less disruption to surrounding neighborhoods.

Implementation challenges of mass timber construction

Of course, using mass timber also comes with some challenges. Here are a few of the most prevalent we’ve seen:

Navigating regulatory approval

The regulatory approval process can be more complex than for conventional materials, particularly regarding fire protection. While building codes continue to evolve, jurisdictional interpretations vary, potentially extending the permitting timeline. This complexity necessitates early engagement with code officials and often requires specialized fire protection expertise.

Supply chain considerations

Material sourcing and supply chain considerations also demand attention. The North American market for engineered wood products like CLT and glulam continues to develop, with manufacturers’ production capacities sometimes struggling to meet growing demand. Lead times for specialized mass timber components can extend to four to six months, requiring early procurement decisions and careful project scheduling. Some East Cost mass timber projects have turned to European manufacturers for shorter lead teams and less carbon-intensive transportation by boat.

Moisture management

Moisture management is also also a concern throughout the construction process. To prevent moisture absorption that could affect mass timber’s structural integrity or appearance, contractors must implement comprehensive moisture protection plans and monitor conditions closely during construction.

Expertise requirements

The specialized nature of mass timber construction often requires procurement, design, and construction expertise that may not yet be widespread in the industry. Design teams need a thorough understanding of mass timber engineering principles, and contractors require familiarity with handling, protecting, and assembling prefabricated wood components. This expertise gap has narrowed as more projects are completed, but it remains a consideration when assembling project teams.

Connectivity challenges

Connecting mass timber elements presents another engineering challenge, often requiring hybrid solutions. Pure mass timber connections are less common than those using steel plates, brackets, and fasteners. These connection details are critical to overall structural performance and require expertise in both mass timber and steel design principles to execute properly.

Regional considerations

Additional design considerations are necessary in regions with high humidity levels to provide long-term performance. While treated mass timber can resist moisture damage, the potential impact on structural capacity must be factored into design decisions. This limitation may make mass timber less suitable for certain tropical or extremely humid environments without additional protective measures.

How Salas O’Brien can help

Salas O’Brien supports clients throughout their mass timber construction journey, from initial concept to completion. Our multidisciplinary teams bring specialized expertise in the technical aspects and practical implementation of mass timber construction, delivering solutions that balance sustainability, performance, and aesthetics.

Here’s how we can help you navigate mass timber construction projects:

• Early-stage feasibility and structural planning. We evaluate mass timber against your project goals, site considerations, and budget, identifying opportunities and challenges before you commit. Our engineers can compare mass timber and hybrid solutions with conventional steel or concrete construction, helping you determine what’s right for your project.
• Embodied carbon accounting. We provide whole-building lifecycle analysis to measure the embodied carbon of your mass timber project and compare it to baseline construction methods. Our sustainability experts can help you find the best approach to meeting your project’s carbon reduction goals.
• Code compliance and fire protection strategies. Our team helps navigate the regulatory landscape, developing solutions that meet stringent safety requirements while maximizing the aesthetic and sustainability benefits of exposed mass timber elements.
• Moisture management and building science expertise. We develop comprehensive strategies to protect mass timber elements during transportation, construction, and throughout the building’s life cycle. This is crucial for the building’s long-term performance.
• Connections to fabricators and integrators. Through our established relationships with mass timber fabricators, we help streamline procurement, reducing lead times and steps required to pass quality control from forest to finished structure. Involving these partners early in the design process is critical to optimizing material use for structural efficiency and embodied carbon reduction
• Coordination with mechanical, electrical, and plumbing systems. Our integrated approach helps building systems work harmoniously with mass timber elements. We can help resolve potential conflicts before construction and optimize overall building performance.

From educational facilities and cultural centers to residential projects and commercial spaces, we’ve helped clients realize the full potential of mass timber construction. By combining technical knowledge with practical experience, we deliver structures that reduce carbon footprints and create beautiful, functional spaces that enhance occupant experiences.

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