Mass Timber vs Concrete at 12 Storeys: Cost, Carbon and Time

A 2026 feasibility study for a proposed residential building in Dartmouth, Nova Scotia, offers a useful mass-timber-versus-concrete comparison because it reports cost, programme and structural carbon together. Its answer is not that one material wins every category. In the study, the mass-timber option had lower modelled A1–A3 structural emissions and a shorter construction programme, while the concrete option had the lower estimated project cost.

The figures are specific to two developed schemes for one proposed building. They should be read as feasibility-study outputs, not measured performance from a completed project and not a universal rule for 12-storey construction.

What the study compared

The proposal contains 199 residential units over 12 storeys, with an amenity penthouse. The mass-timber scheme is hybrid rather than all-wood: it uses 11 timber-framed levels over a concrete podium, with concrete cores and below-grade construction. The comparison is an optimised reinforced-concrete alternative prepared for the same project brief.

This distinction is important. The study did not replace each cubic metre of concrete with a predetermined quantity of timber. It developed two structural approaches, each with its own material inventory, sequencing and cost implications.

The report was prepared to test feasibility and inform a project decision. The building remained a proposal when the study was released.

The reported cost difference

Including site work, the report estimated:

• mass-timber option: $65.96 million;

• reinforced-concrete option: $61.15 million.

The reported premium for the mass-timber option was 8.39%. These are study estimates in the report’s stated dollar basis and at its pricing date. They are not supplier quotations for another site.

The result also shows why “cost parity” should not be inferred from a carbon result. Labour availability, procurement timing, local supply, temporary works, fire strategy, façade interfaces and financing assumptions can influence the comparison. A project in another market would need current quantities and prices.

The reported programme difference

For the superstructure, the study estimated six months for mass timber and ten months for reinforced concrete. That is a four-month, or 40%, reduction in the modelled superstructure period.

At whole-project level, the difference was smaller: 24 months for the mass-timber scheme and 26 months for concrete. The reported overall advantage was therefore two months, or 7.7%.

Both numbers can be correct because the superstructure is only one part of the total programme. An article should not turn the four-month structural difference into a claim that the entire project finishes four months earlier.

Programme estimates are particularly dependent on project logistics and the assumptions used by the study team. They show the opportunity identified for this proposal, not a guaranteed construction duration.

The A1–A3 structural carbon result

The report’s carbon comparison covers the structure and product stages A1–A3. It reports:

• mass-timber structure: 2,524,355 kgCO₂e, or 138 kgCO₂e/m²;

• reinforced-concrete structure: 3,750,393 kgCO₂e, or 205 kgCO₂e/m²;

• difference: 1,226,038 kgCO₂e, reported as 39%.

This is the strongest finding to connect with an early embodied-carbon calculator, but its boundary must remain attached to the number. It is not a 39% reduction for every building component, the construction site, operational energy or the full life cycle.

The study separately reports 2,629 tonnes of CO₂e as biogenic carbon stored in the timber. It then presents a larger “total potential benefit” when avoided emissions and storage are considered together. For clear decision-making, the product-stage emissions and stored-carbon indicator should remain separate. Storage depends on accounting conventions, sourcing and future scenarios; it is not the same thing as avoiding a fossil emission today.

What the result does and does not show

The study supports four limited conclusions:

• A hybrid mass-timber scheme was technically developed for this 12-storey brief.

• Its modelled A1–A3 structural emissions were lower than those of the study’s concrete alternative.

• Its estimated superstructure and overall programmes were shorter.

• Its estimated project cost was higher.

It does not establish a standard carbon reduction, cost premium or schedule saving for tall timber. It also does not isolate material choice from all other design changes.

A separate peer-reviewed US Forest Service study of functionally equivalent 12-storey timber and reinforced-concrete buildings illustrates the boundary problem. Its reported advantage changed substantially when the assessment moved from life-cycle stages A–C to a scenario including module D. That is why the Dartmouth result must remain labelled A1–A3.

Recreate the right part with your own quantities

The FrameVerk Embodied Carbon Calculator can support the product-stage portion of a similar early comparison. Enter the actual timber, concrete and steel quantities for a baseline and an alternative, then apply documented A1–A3 factors with matching units.

The useful action is: “Run the same A1–A3 comparison with your quantities.”

The calculator will not reproduce the Dartmouth study from its headline figures alone. It does not model structural design, validate equivalent performance, estimate cost or programme, calculate A4 transport, account for construction-stage energy, or complete a whole-life assessment. The project inventories and assumptions still have to be developed and reviewed.

Questions to ask before transferring the finding

Before applying the study to another project, ask:

• Is the building use, height, grid and structural function comparable?

• Does the proposed timber option still require a concrete podium, cores or other hybrid elements?

• Are the carbon factors regional and current?

• Does the comparison cover structure only or the whole building?

• Are biogenic storage and avoided emissions reported separately?

• Are cost and schedule assumptions current for the project location?

The Dartmouth study is valuable because it exposes trade-offs rather than hiding them. Used carefully, it can frame a better feasibility discussion. Used as a universal 39% promise, it would say more than the evidence supports.

Sources

• Canadian Wood Council, “Tall Wood Feasibility Study: Mass Timber and Concrete,” April 2026, primary report: https://cwc.ca/wp-content/uploads/2026/04/Apr2726_CWC_TallWoodFeasibilityStudy.pdf

• Atlantic WoodWorks, study overview and project context, accessed 30 July 2026: https://atlanticwoodworks.ca/tall-wood-feasibility-study/

• Daily Commercial News / ConstructConnect, independent project coverage, May 2026: https://canada.constructconnect.com/dcn/news/projects/2026/05/atlantic-canadas-first-tall-mass-timber-tower-dartmouth-study-compares-mass-timber-vs-concrete

• US Forest Service Research and Development, “Comparative Life Cycle Assessment of Cross Laminated Timber Building and Concrete Building,” 2020: https://research.fs.usda.gov/treesearch/60576