What is hybrid-timber construction?

A vast number of buildings today are erected using hybrid construction. Hybrid-timber construction systems combine wood with different materials (e.g. steel, concrete and glass) and techniques to deliver a wide range of structural solutions. While it is possible to construct a building entirely of wood, most wood buildings rely on some use of other materials. Nails, screws, bolts and plates for connections are a standard complement to wood construction. Hybrid-timber construction goes further, making other materials—such as steel and concrete—an integral part of a building’s structural assemblies. This mixing of materials in building systems means design teams can exploit the strength of each—optimizing structural and building performance. Projects might use one specific hybrid assembly while others might take advantage of multiple configurations.

Central City, Surrey
Photo credit: Nic Lehoux

Architecturally expressive low-carbon building solutions

Advancements in hybrid-timber technologies are giving rise to taller, larger, and long-spanning wood structures from office high-rises and residential towers to industrial warehouses and sports stadiums.

These expressive structures are often an architectural focal point, serving both a practical and aesthetic function. As a lighter assembly, hybrid-timber systems save on foundation costs and can improve seismic performance during an earthquake. And by increasing the amount of wood, these systems lessen a building’s overall environmental impact and offer a lower carbon solution.

Examples of hybrid-timber construction include post-tensioned timber systems, wood-concrete composite systems and mass-timber combined with light-frame wood construction.

Askew’s Uptown Supermarket, Salmon Arm
Photo credit: Derek Lepper Photography

Mass timber combined with light-frame construction

Mass timber combined with light-frame construction is a nearly all-wood hybrid building system. It offers unique opportunities not possible with light-frame construction alone, such as a cantilevered design element.

Prefabricated mass timber light-frame systems offer several advantages: fewer crew members needed on site, a smaller carbon footprint, a high building-volume-to-surface-area ratio for generous interiors, lighter weight and lower foundation costs, natural insulation that offers thermal advantages, and the ability to flex during an earthquake. When mass timber is left exposed, these projects have the bonus of aesthetic warmth and biophilic benefits.

Legacy on Park Avenue, Langley
Photo credit: courtesy Keystone Architecture

Panel what you preach

Okanagan College’s Jim Pattison Centre of Excellence walks the talk with its sustainable design

This learning hub dedicated to teaching the latest in sustainable construction and design leads by example with its less carbon-intensive timber-concrete composite panels forming the walls and roof of this 1,100 m2 gymnasium.

Okanagan College Jim Pattison Centre Of Excellence, Penticton
Photo credit: courtesy CEI Architecture

 

Timber-concrete composite systems

Timber-concrete composite technology, chiefly used for reinforced flooring but can also form wall panels, is essentially a prefabricated concrete slab connected to a timber panel or beam. The materials work together to optimize structural performance. The concrete resists compression while the wood, with its capacity to flex, offers tensile strength. Either solid mass timber panels (e.g. NLT, CLT) or engineered wood beams spaced at centres (e.g. Glulam, LVL) can be used. The concrete slab can be poured on-site or precast in a shop environment. On-site pours reduce the weight of the timber panels and, without additional topping, creates a structural diaphragm—a flat horizontal platform that strengthens the structure and transfers lateral loads to the vertical columns of the building.

Okanagan College Jim Pattison Centre Of Excellence, Penticton
Photo credit: courtesy CEI Architecture

Improved structural and acoustic performance is a primary benefit of timber composite systems. Electrical and mechanical systems can be integrated into the structural panels as part of the prefabrication process. Another advantage of timber-concrete composite technology is that it requires less concrete than conventional construction methods, shifting load to the timber. Reducing the use of carbon-intensive concrete and increasing the use of low-carbon timber means a smaller environmental footprint.

Brock Commons Tallwood House, UBC
Photo credit: KK Law

 

Concrete thinking

FPInnovation’s Design Guide for Timber-Concrete Composite Floors in Canada

Topping timber floors with concrete offers benefits from enhanced load-carrying capacity and stiffness to better acoustic performance. Learn more in this 100-page guide by FP Innovations, complete with illustrations, formulas and project examples.

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