Concrete builds most of Canada's mid-rise housing. It always has. You pour it, form it, cure it, repeat for twelve floors, and at the end of a long and loud two years, you have an apartment building. The method is slow, carbon-heavy, and expensive, but it's familiar, and familiar is a powerful force in construction.

So when a developer in Dartmouth, Nova Scotia, commissioned a rigorous side-by-side feasibility study comparing mass timber to concrete for a proposed 12-storey purpose-built rental, the industry paid attention. Not because the results were conclusive, but because they were close enough to make the conversation real.

The study, funded by WoodWorks Atlantic and produced with ASPECT Structural Engineers and Fathom Studio, compared optimized designs for both materials on the same site. Mass timber came in 8.39% more expensive than concrete. At first glance, that sounds like the story ends there. It doesn't.

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What 8.39% Actually Means

Cost comparisons in construction are almost never as clean as a single percentage. The 8.39% gap is the sticker price difference. What you do with that number depends on how you account for time, revenue, and capital.

The study found that mass timber could deliver the building up to four to six months ahead of a concrete schedule, according to Joe Nickerson, partner and vice-president at Sidewalk Real Estate Development. For a rental building, that's not a scheduling footnote. That's four to six months of rent you're collecting earlier. Combine that with a lighter structural system (mass timber buildings can be roughly one-fifth the weight of equivalent concrete structures), which means a shallower, cheaper foundation, and the cost gap starts to narrow considerably.

Nickerson says Sidewalk's "conservative calculations" put exposed-timber suites at only about a $50 per month premium over standard drywall units. When you add earlier occupancy, lighter foundation costs, and even a modest rent premium for the warmth of visible wood, the developer says mass timber reaches near cost parity with concrete. That's the math that matters to a developer running a pro forma.

This is not a theoretical exercise. The Dartmouth project is a real development Sidewalk is actively trying to get into the ground. It would be the first mass timber tower above six storeys in Atlantic Canada, a region where encapsulated mass timber construction at 12 storeys has been permitted under the 2020 National Building Code but has never been built at that height.

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The Honest Complications

None of this is simple. If it were, every developer in Canada would already be building with wood.

The most immediate friction point is insurance. Builder's risk premiums for the Dartmouth mass timber design came in between $475,000 and $750,000. The concrete version? $250,000 to $475,000. That's a meaningful gap at the project level, and it's not unique to this development. Across Canada, mass timber builder's risk insurance runs six to ten times higher than for equivalent concrete and steel buildings, according to the Climate Smart Buildings Alliance and Canadian Wood Council. The reason is structural: insurers don't have enough historical loss data on mass timber buildings to price the risk confidently, so they charge a premium for the uncertainty. A Mass Timber Insurance Action Plan launched in 2024 is working to close that data gap, but it's a slow process. The gap won't disappear before the Dartmouth decision gets made.

There's also the financing problem, which Nickerson articulated clearly. Mass timber's prefabricated nature means you're paying for panels and systems before they're on site, before any lender can see visible progress. Traditional construction financing releases funds as concrete formwork climbs above grade. Lenders are frequently hesitant to release large funds to offsite fabricators without onsite evidence of construction. It's a capital-flow mismatch that adds real pressure to early project stages.

Then there's the coordination problem. Mass timber erects quickly, but only the structural frame. The electrical, mechanical, and window wall systems still take the same time they always did. Nickerson asked it directly in the study: can the other trades catch up to a faster-erected structure? The answer, at least for now, is: sometimes. Building Information Modelling can help, and the study noted its potential to improve coordination across disciplines, but integrating BIM into a project team that isn't already fluent in it adds its own friction.

And there's one more wrinkle on this specific project. The Dartmouth site is currently zoned for 10 storeys, not 12. The mass timber design needs 12 to work. That zoning variance isn't guaranteed, and Nickerson was direct about its importance: a successful rezoning would, in his words, be enough to push them to mass timber. Federal grant funding, which could offset the higher early capital costs, is the other tipping point he identified.

Two things outside the developer's direct control are now effectively deciding what gets built.

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Why the Carbon Case Keeps Getting Stronger

Even setting aside the cost math, the environmental argument for mass timber continues to harden. RBC estimates that widespread adoption of mass timber in Canadian apartment and office construction could cut embodied emissions by at least nine megatonnes by 2030, nearly 10% of the building sector's total. A peer-reviewed Canadian life-cycle study found that mass timber reduces embodied carbon by 33 to 36% compared to reinforced concrete in three- to six-storey buildings, even before accounting for the carbon stored in the wood itself.

Concrete's production is energy-intensive and essentially impossible to decarbonize with current technology. Mass timber sequesters carbon through the lifespan of the building. It's not a close comparison on emissions, which is why Sidewalk explicitly named decarbonization as a driver behind this project, not just as a nice-to-have.

The post-and-beam structure Sidewalk has in mind would combine CLT floor panels with glulam beams, possibly with concrete cores and stairwells for lateral stability and a concrete foundation. That kind of hybrid is increasingly common in Canadian mass timber projects. It lets you use each material where it performs best, rather than forcing timber into structural roles where concrete simply works better.

One notable detail from the study: Sidewalk found a "clear pathway" to expose the timber in suites rather than encapsulating it entirely behind drywall. Under an alternative compliance approach, they can keep the warm, visible grain that tenants actually want to live with, without compromising fire safety requirements. That exposure is what justifies even a modest rent premium and it's what makes the financial case for timber work at all. If you drywall over everything, you've built a concrete building with a more expensive structure.

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What This Tells You About Where Canadian Construction Is Heading

BC has been doing mass timber at scale for years. The Brock Commons student residence at UBC opened in 2017 as one of the world's tallest hybrid mass timber buildings, 18 storeys, erected in 66 days. BC now permits mass timber up to 18 storeys after further code updates. Atlantic Canada is genuinely behind.

But that gap is closing, and the Dartmouth study is part of how it closes. Real feasibility data, attached to a real site, with a real developer willing to publish the numbers, is what shifts the industry. Developers elsewhere can now look at Sidewalk's work and run their own numbers with a concrete starting point instead of guessing.

The study also proves something more basic: mass timber isn't unaffordable at 12 storeys. It's not cheap. It's not yet as cheap as concrete at scale, especially in markets where mass timber suppliers are sparse, trades experience is limited, and insurers are still pricing uncertainty into every quote. But 8.39% is not a prohibitive gap. It's a negotiating position. And the trajectory, as more projects get built, more data accumulates, and more trades get experience, is toward cost parity.

Nickerson's comment about rolling the model out across tight Halifax infill sites says something important. He isn't building one wood building. If this project works, he's building a template.

Atlantic Canada hasn't had one yet. Dartmouth might be it.