Mass timber: reducing carbon in the built environment

The role of mass timber construction in supporting global decarbonization is in the spotlight across North America—especially as building-code limits have eased.

Offering proven efficiencies in both schedule and cost, while also drawing attention for its architectural warmth and aesthetic qualities, mass timber is increasingly part of the conversation as owners and developers pursue net-zero targets.

Despite recent volatility in the lumber market, we’ve seen a significant uptick in clients choosing mass timber—using engineered wood products as an energy-efficient alternative to steel and concrete—to meet their sustainability goals.

That’s because mass timber generates less waste, carries a lighter carbon footprint, and can be faster and more cost-effective than traditional construction approaches.

According to market research published by MarketsandMarkets™,, the global cross-laminated timber (CLT) market is projected to grow at 14.5% annually, rising from $1.1b in 2021 to $2.5b by 2027.

The 2021 Mass Timber Report, published by the Forest Business Network, projected an increase in mass timber projects from just below 100 projects in 2018 to nearly 25,000 in 2034.

This is a clear signal that many clients may now see greater opportunity in prioritizing net-zero ambitions over potential risks related to pricing and limited workforce experience.

Updated building code

In January 2021, proposals for tall wood buildings were approved in the 2021 International Building Code (IBC). This now allows mass timber buildings up to **270 feet (82.2 meters)**—roughly 18 stories—a major jump from the previous six-story cap. This updated policy has had a compounding effect on the number of mass timber buildings planned for construction.

For example, Milwaukee is home to the USA’s tallest mass timber building (image above). This 25-story, 493,000 SF mixed-use residential building was completed in 2021 and is expected to be one of many tall mass timber buildings across the country.

Lighter carbon footprint

Projected global construction growth between now and 2060—without considering embodied carbon—is anticipated to add the equivalent of an entire New York City footprint to the world every month for the next 40 years. Today, the built environment generates nearly 50% of annual global CO₂ emissions.

While building operations emissions (operational carbon) can be reduced over time through energy upgrades and the adoption of renewable energy, the carbon footprint of building materials (embodied carbon) is largely locked in once construction is complete.

As the industry works to reduce embodied carbon, mass timber has increasingly captured attention as a lower-carbon alternative to traditional steel and concrete.

Compared with concrete buildings, mass timber produces 30% fewer CO₂ emissions. That figure increases to 50% fewer emissions compared with steel buildings. If the industry wants to make meaningful progress, mass timber is a compelling solution in North America.

From electrifying existing buildings and transitioning to renewable power sources, to adopting less conventional construction materials and methods to reduce embodied carbon, there are a growing number of options available to those looking to decarbonize their built assets.

Construction efficiency

We recently completed a study comparing cost and schedule for a Seattle office building using mass timber versus steel and concrete. We concluded that steel cost 11% more than mass timber and extended the construction schedule by 7%.

A cost comparison with concrete was similar (within 1%), but concrete extended the schedule by 31% compared with mass timber. A similar study completed by Robert Jackson at Fast+Epp Structural Engineers found comparable results.

As with traditional building methods, mass timber’s benefits vary depending on design. For example, a mass timber building is typically more cost-effective for large, regularly shaped structures and where fabrication is repetitive.

As a result, it is more likely to be—and should be—recommended for projects such as office buildings or apartment buildings where floor layouts are consistent throughout.

Adidas campus expansion

The recently completed expansion at adidas’ North American headquarters achieved accelerated delivery when the project team developed a precast concrete and mass timber hybrid structure—reducing the schedule by three months.

The timber, locally sourced and manufactured in Oregon, sequesters carbon from the atmosphere and offers a smaller overall carbon footprint than other building materials. It was among the first of its kind in the USA.

While there are many benefits, mass timber construction does have limitations. For example, a standard 5-ply CLT floor structure can span only up to 17 feet, which can increase the number of columns required.

That said, while additional columns may mean more piles, overall foundation depth may be reduced compared with concrete and steel columns due to mass timber’s lighter weight.

A mass timber future

Mass timber is gaining traction across North America, supported by evolving building codes and a broader push for a more sustainable built environment.

While cost will remain a key driver for many projects, we are already seeing a shift in how the material can help meet net-zero targets. As a local resource—without the constraints and uncertainty that can come with global supply chains—mass timber in North America offers substantial benefits and should be a key consideration for upcoming building projects, supporting a more productive and sustainable future.