Large hybrid mass timber projects rarely succeed because of one discipline alone. They succeed when architecture, structural engineering, and construction execution align early and stay aligned throughout design and delivery.

This session "Scaling Affordable Rental Housing with Tall Mass Timber" organized by Canadian Wood Council offered a practical look at one such project from three perspectives: the architectural practice responsible for the building design, the structural engineering team responsible for the hybrid system, and the construction manager leading project delivery. Together, their observations provide a clear picture of what actually determines whether a tall timber building performs technically, financially, and operationally.

1. Project Context Introduced by the Design Architect

A hybrid mass timber tower with a complex civic program

The architectural team described Phase Two of a broader site development consisting of an 18-storey hybrid mass timber building. The tower rises above a three-storey concrete podium, which itself sits on three levels of underground parking.

The residential portion of the building includes 179 affordable housing units, organized on cross-laminated timber floor plates of approximately 8,400 square feet.

However, the project is not a typical residential tower. The design architect explained that the podium incorporates a number of community functions, including:

• a childcare facility,

• municipal office space for the City of North Vancouver,

• disaster recovery support facilities,

• and food bank services.

Each of these users introduced different operational requirements, accessibility standards, and infrastructure needs. The design team therefore had to reconcile multiple stakeholder requirements within a single building envelope.

Energy performance targets shaped the architecture from the beginning

The architects explained that the building was required to meet an aggressive energy target that effectively limited the overall window-to-wall ratio to roughly thirty percent across the entire tower and podium.

For tall buildings this constraint is significant. Tower architecture often relies on extensive glazing, but the design team noted that achieving the required energy performance demanded a much tighter façade strategy.

Several envelope decisions followed directly from that requirement:

• high-performance prefabricated façade assemblies,

• thermally efficient punched window configurations,

• thermally isolated envelope penetrations,

• and a prefabricated balcony system designed to reduce thermal bridging.

The architectural team emphasized that establishing these parameters early allowed the tower massing and façade design to evolve in a coordinated way rather than forcing major redesign later.

Accessibility requirements added another layer of coordination

Beyond energy performance, the architects described a complex set of accessibility obligations tied to both provincial building code requirements and municipal expectations.

The project includes:

• barrier-free common areas,

• a minimum proportion of British Columbia Building Code accessible units,

• adaptable unit requirements specific to the City of North Vancouver,

• and accessibility goals associated with the podium’s civic functions.

The architectural team characterized the challenge not as individual accessibility details but as coordinating overlapping standards across different building programs and stakeholders.

2. Permitting Strategy Discussed by the Architects

Early alignment with the authority having jurisdiction

Permitting timelines in the Vancouver region can be lengthy, but the design team reported that this project progressed from design inception to building permit in roughly twelve months, which they considered unusually fast.

Several factors contributed to that timeline.

First, the overall site had already been rezoned, which meant this phase avoided the entitlement process and focused only on development permit and building permit approvals.

Second, the architects stressed the importance of early discussions with the city’s building department regarding tall timber construction, potential alternate-solution pathways, and material procurement timelines.

By raising these issues early, the team avoided later surprises during the review process.

Using digital models to accelerate municipal review

Instead of relying solely on traditional drawing packages, the design firm presented the building to municipal staff using an interactive three-dimensional model.

City reviewers were able to navigate the model directly, slice sections through the building, and review structural and code conditions visually rather than interpreting hundreds of pages of two-dimensional drawings.

According to the architectural team, this approach helped reviewers understand the design faster and allowed technical discussions to focus immediately on the areas that mattered most.

3. Structural System Decisions Explained by the Engineering Team

Tall mass timber rarely means “all timber”

The structural engineers began by clarifying an important misconception: most tall timber buildings in seismic regions are hybrid structures.

In this case, the structural scheme combines:

• a reinforced concrete core for seismic resistance,

• cross-laminated timber floor panels,

• steel columns supporting the timber structure,

• and a concrete podium supporting the tower above.

The engineering team explained that each material was used where it performs best structurally and economically.

Comparing two common timber framing systems

During early design studies, the engineering consultants examined two primary structural options.

One approach, known as post-and-panel construction, uses closely spaced timber columns with cross-laminated timber panels spanning directly between them. This configuration creates a flat ceiling surface that simplifies mechanical and electrical distribution.

The alternative approach, post-beam-and-panel construction, introduces beams between columns. While this allows for wider structural grids, it creates a deeper floor assembly and adds complexity for service routing.

After evaluating fabrication constraints and structural performance, the engineering team recommended the post-and-panel configuration as the most efficient option for this particular project.

Structural efficiency influenced the building layout

The engineers emphasized that efficient timber buildings require architectural layouts that align with structural panel dimensions.

Manufacturing limits on panel width and transport constraints tend to produce optimal grid spacing around ten to fifteen feet. The tower design therefore followed a relatively consistent structural module that allowed timber panels to be fabricated efficiently.

Rather than treating structure as an afterthought, the project team allowed the structural system to influence elements such as:

• balcony placement,

• façade rhythm,

• and interior unit planning.

The engineering consultants argued that this alignment between architecture and structure is essential if tall timber construction is to compete economically with conventional concrete buildings.

Balcony integration posed both structural and envelope challenges

Balconies can be particularly complicated in timber buildings because of structural loading and thermal bridging concerns.

The engineering team described how recessed balconies helped simplify the system. Instead of cantilevering large balcony slabs from the building perimeter, the recessed configuration allowed balcony loads to span between structural walls.

This reduced the need for heavy edge beams and simplified the connection between the balcony structure and the façade.

Engineering considerations around panel performance

The structural consultants also discussed rolling shear, a potential failure mechanism within cross-laminated timber panels. Although detailed procedures for this phenomenon are still evolving in Canadian design standards, the engineering team noted that widely accepted analytical methods and research studies are already available.

When presented with supporting documentation and calculations, authorities having jurisdiction generally accept these analyses as part of an alternate-solution approval process.

Life-cycle analysis of the hybrid structure

To better understand the environmental implications of the design, the engineering team conducted a life-cycle assessment comparing the hybrid timber tower with a conventional concrete alternative.

Their analysis suggested that the hybrid system could reduce embodied carbon by roughly fifteen percent, even after accounting for additional steel hardware used in diaphragm connections and structural fasteners.

The engineers also observed that the lighter timber superstructure reduced loads on the transfer slab, columns, and foundations, creating additional material savings elsewhere in the building.

4. Construction Strategy Shared by the Builder

Urban site logistics favour prefabrication

The construction manager responsible for delivering the project described a typical challenge of building in the Vancouver region: extremely tight sites with limited staging space.

Prefabrication offered clear advantages in this environment. Components such as timber panels, façade elements, and balcony assemblies could arrive partially completed and be lifted directly into position, reducing on-site labour congestion.

However, the builder emphasized that prefabrication only works well when manufacturing speed and installation speed are carefully balanced.

If components arrive faster than the site team can install them, projects must rely on off-site storage areas, which introduces additional logistical risks.

Crane planning must begin during design

Another lesson from the construction team involved crane logistics.

Urban construction sites rarely allow cranes to be positioned wherever convenient. Because large prefabricated components must be lifted into place, crane reach, capacity, and location must be considered early during design.

Ignoring this constraint can result in inefficient lifting sequences or oversized components that cannot be safely installed.

Coordinating concrete and timber construction sequences

The builder also highlighted the importance of sequencing.

By completing the concrete core and podium first, the team could begin installing mass timber floors immediately afterward while maintaining efficient crane utilization.

In some cases, secondary lifting equipment can also be introduced to reduce competition for crane time and keep multiple installation activities moving simultaneously.

Moisture management is critical for mass timber

The construction manager devoted significant attention to moisture control.

Timber panels are typically protected during shipping and storage, but once the protective wrapping is removed for installation, the material becomes vulnerable to weather exposure.

The builder stressed that the best strategy is preventing moisture exposure rather than trying to dry panels later. Once water penetrates thick timber panels, drying them can take a very long time and may compromise performance.

Rapid enclosure of the building envelope therefore becomes a critical milestone.

Procurement strategies strongly influence schedule outcomes

Perhaps the most important insight from the construction side involved procurement timing.

Traditional design-bid-build delivery models often bring specialized suppliers into the project too late. When manufacturers are engaged only after design is complete, the team frequently must revise details to suit fabrication constraints.

This redesign period can eliminate the schedule advantages that prefabrication is supposed to deliver.

The builder recommended earlier engagement of key suppliers and trades, allowing the design team to coordinate systems once rather than redesign them later.

Digital coordination is valuable but not fully integrated contractually

Finally, the construction manager noted that while building information modelling has become an essential coordination tool, many project contracts still treat two-dimensional drawings as the governing documents.

This disconnect can create uncertainty about who owns the digital model and how it should be used during construction.

As prefabrication becomes more common, the industry will likely need to update contractual frameworks so that digital models can play a more formal role in project documentation.

5. What the Architect, Engineers, and Builder Agreed On

Despite approaching the project from different professional perspectives, all three groups converged on several key principles.

Early decisions determine success.
Energy targets, structural grids, façade strategies, and procurement approaches must be defined early enough to shape the design rather than constrain it later.

Tall timber buildings are integrated systems.
Concrete cores, timber floor panels, steel columns, façade assemblies, and balconies must be designed as one coordinated structural and architectural system.

Prefabrication only creates speed when the delivery model supports it.
Without early supplier involvement and coordinated procurement planning, prefabrication can actually slow projects down.

Moisture protection and rapid enclosure are essential.
Keeping mass timber dry is far easier than repairing water damage after installation.

Collaboration with authorities can accelerate approvals.
Providing clear digital models and discussing alternate solutions early helps regulators understand innovative construction systems more quickly.