How Hybrid Species Glulam Can Strengthen Mass Timber

by Fast + Epp Structural Engineers/photos by Josh Hall at Spearhead

Mass timber’s rise in North American construction has been one of the industry’s defining stories over the past decade. Glued-laminated timber (glulam, or GLT) has moved from a niche structural material to a mainstream choice for architects designing schools, office buildings, community centers, and mid-rise residential projects from coast to coast. Its warmth, structural efficiency, and carbon credentials have made it a natural fit for a design culture increasingly focused on the embodied carbon impact of the built environment.

But there are further opportunities to be explored. Glulam in North America runs almost entirely on softwood in structural applications: Spruce-Pine-Fir, primarily, with some Douglas Fir and Southern Yellow Pine. As mass timber has grown, so has demand for these species and questions about long-term fiber supply, cost stability, and whether we are leaving an enormous opportunity untapped. North America’s diverse hardwood forests represent a resource that remains largely underutilized in structural applications.

AN IDEA READY FOR NORTH AMERICA

Hybrid species glulam leverages the strength of hardwoods in combination with the softwoods typically used in construction to create a high-value, high-strength engineered wood product. This concept is an established approach in Europe, where engineered wood products that combine hardwood and softwood laminations within a single beam or column have been in commercial use for over a decade. Beech and ash are routinely integrated with softwood cores in German and Swiss manufacturing facilities, producing members with higher strength, greater stiffness, and distinctive material character.

Robert Jackson, Partner at Fast + Epp, encountered this firsthand while visiting the firm’s offices in Germany. European operations gave him a front-row view of a product category that has matured commercially but is not yet available in the North American market.

"The European timber industry has already demonstrated that hybrid glulam works structurally and commercially. The question we came back with was: why isn’t this happening in North America, with North American species? That seems like an opportunity worth pursuing."

— Robert Jackson, Partner, Fast + Epp

Fast + Epp set out on that pursuit. For the past two years, the firm has led a research program funded primarily through Natural Resources Canada’s Investments in Forest Industry Transformation (IFIT) program to investigate the structural potential of hybrid species glulam using North American hardwood and softwood species. The program brings together glulam manufacturers Element 5, Art Massif, Nordic Structures, and FraserWood, alongside academic partners at the University of Alberta, Lakehead University, and the University of Northern British Columbia.

THE ENGINEERING OPPORTUNITY

The case for hybrid species glulam is rooted in the way a glulam beam works. Unlike natural logs and timbers, glulam is an engineered assembly of individual laminations. In a beam supporting bending loads, the outermost laminations carry the highest stresses — tension at the bottom, compression at the top — while the interior laminations carry significantly less force. By placing high-strength, high-stiffness hardwood laminations in the high-stress outer zones and using softwood in the lower-stress interior, it becomes possible to produce beams that outperform conventional all-softwood glulam. The inverse logic applies too: lower-density species such as poplar and aspen, placed selectively as interior laminations within a high-grade softwood outer zone, offer a path to incorporating underutilized species into a structural product at commercially viable price points. Hardwood glulam also has significant opportunity for structural columns, which carry enormous loads in mid- to high-rise (12-24 story) mass timber construction.

“What’s compelling about the hybrid approach is its flexibility. We’re not developing a single product but rather a performance-based framework that lets designers and manufacturers optimize for strength, cost, or species availability depending on their market and their forest resources. That adaptability is what makes this project relevant across a wide geography and range of species.”

— Carla Dickof, Principal and Director of Research and Development, Fast + Epp

The hardwood species currently being assessed include White Oak, Sugar Maple, Yellow Birch, White Ash, American Beech, Red Alder, Balsam Poplar, and Quaking Aspen — reflecting the diversity of Canada’s hardwood resources from the mixed forests of Ontario and Quebec to the coastal species of British Columbia. They are being evaluated in combination with softwood species including Alaskan Yellow Cedar, Western Red Cedar, White Spruce, Western Hemlock, and Douglas Fir.

WHAT THE RESEARCH IS TESTING

Fast + Epp’s Concept Lab — the firm’s dedicated in-house research and development facility in Vancouver — has served as the hub of the testing program. The work has focused on two questions any new structural material must answer before it reaches a design desk: can it be manufactured reliably, and does it perform as the engineering predicts?

On the manufacturing side, the research has examined adhesive bonding and finger-jointing — the connections between individual laminations that are essential to commercial-scale glulam production. Hardwood species present different bonding challenges than softwoods: their density, surface chemistry, and moisture behavior require careful optimization of adhesive selection, surface preparation, and pressing conditions. The team has worked through these variables systematically in the lab and with manufacturing partners.

To understand structural properties, small-scale and mid-scale testing is characterizing the mechanical behavior of hybrid assemblies in bending, tension, compression, and shear. A fire testing program, conducted in partnership with Lakehead University’s Fire Testing Research Laboratory, is the next step to specify hybrid glulam in the mid- to high-rise construction market.

“The testing program we’ve built is rigorous by design. We’re generating data that engineers and code bodies need to specify hybrid glulam with confidence. That means thousands of physical test specimens, documented results, and a clear path to design values which will build the foundation for a real product that can reshape our buildings.”

— Brandon Sullivan, Concept Lab Manager, Fast + Epp

THE OPPORTUNITY FOR ARCHITECTS AND DESIGNERS

For the design community, this research carries implications beyond structural performance.

Hardwood species offer a different visual character than conventional softwood glulam, with grain patterns and tones of species such as maple, ash, and beech introducing a broader material palette. Architects and designers are already familiar with these species through their use in millwork, flooring, and cabinetry, where their appearance and performance are well understood. Hybrid species glulam could extend those qualities into the structure of a building, where the material becomes part of the architectural expression.

The sustainability potential goes beyond carbon sequestration. Some of the hardwood species in this study, such as poplar and aspen, are already harvested across North America, but their use is often limited to select applications such as pulp, pallets, or lower-grade lumber. Developing these species into a structural product creates economic incentive for diverse, multi-species forest management while expanding the value of existing harvests and supporting ecological resilience.

WHAT COMES NEXT

The current research program runs through early 2027, and additional large scale testing phases will follow, with the long-term goal of achieving codification of hybrid species glulam under Canadian standards. In parallel, Fast + Epp intends to build upon the current test program to encompass American species, American manufacturers, and US code pathways.

“We want to continue the story of timber innovation in Canada, building on our long history of engineered wood products. Hybrid species glulam can be made with our species, our manufacturers, and our design community. The forest resources are here. The engineering case is strong. Now we’re building up the research to empower the engineering community and the laminators to define the final form of hybrid species glulam.”

— Robert Jackson, Partner, Fast + Epp

Although not yet commercially available, hybrid species glulam research is advancing rapidly and the path to code-compliance is clear, offering architects and designers a material worth watching.

Fast + Epp Structural Engineers is a Vancouver-based structural engineering firm with offices across North America and over three decades of experience in mass timber design and innovation. The hybrid species glulam research program is funded by Natural Resources Canada’s Investments in Forest Industry Transformation (IFIT) program, with additional support from BC Forestry Innovation Investment, Ontario MNRF, Alberta Innovates, NSERC, and industry partners.