The savings didn’t come from the wood. They came from what the wood let the team stop building.
Mortenson has published a cost breakdown on Kaiser Borsari Hall, a four-storey, $55 million academic building at Western Washington University in Bellingham that broke ground in 2023 and opened in early 2025. The contractor puts the mass timber savings at about $2 million against a steel-framed alternative, and the single biggest line in that total is a basement that never got dug. A mass timber structure is lighter, the foundation loads drop, and the below-grade level that was carrying the foundation economics stopped being necessary.
What else moved
The rest of the number is ordinary value engineering that the structural change made available: less concrete volume overall, a switch to a variable refrigerant flow HVAC system, and a re-routed sewer connection. Mortenson also reports a schedule reduction of roughly 25%, with timber installation itself running about two months ahead of the steel sequence it replaced. Prefabrication and the near-absence of welded connections cut both site labor and delivery counts.
Perkins&Will was architect. Kalesnikoff, in British Columbia, fabricated the timber and trucked it roughly 600 miles. Tiger Construction, out of Washington, did the installation; McKinstry handled mechanical.
Read the two claims separately
The $2 million and the 25% are Mortenson’s own back-calculation against a building that was never built. There is no independent audit of the counterfactual, and there can’t be. Take them as a contractor’s account of its own project, which is what they are.
The certification is a different class of evidence. Kaiser Borsari Hall earned Zero Carbon and Zero Energy certification from the International Living Future Institute following a 12-month performance audit, meaning the building was measured in operation rather than modelled at design stage. Very little of what gets published about low-carbon buildings clears that bar.
The geography caveat
Paige Nowoj, a Mortenson project manager, put the limit on the finding plainly: “Building with wood in Arizona is very different from building with wood in the Pacific Northwest.” A 600-mile supply chain, a regional erector crew that has done this before, and a code environment that is comfortable with tall timber are all Pacific Northwest conditions. Move the same building to a market with none of those and the foundation savings survive while the schedule savings probably don’t.
The supplier is also Canadian, which puts this project’s economics inside an active lumber trade question that didn’t apply when it was bid in 2023.
For owners pricing a mid-rise institutional building, the useful takeaway isn’t the $2 million. It’s the mechanism: ask early whether a lighter structure removes a foundation scope, because that is where the money was, and it only shows up if the question gets asked before the geotechnical report becomes a design assumption.
Source: Construction Dive, 2026-09-23.