Mass timber is arguably the most exciting and innovative building material in the history of modern industrial construction and it’s a technology that is still in its infancy.
Mass timber (short for “massive timber”) is a broad term for structures built using engineered wood products, like glue-laminated beams (glulam), nail-laminated timber (NLT), and cross-laminated timber (CLT). Mass Timber Framing (MTF) is an alternative structural framing system that can be used in place of a CIP Concrete, Structural Steel, or conventional wood framing system.
Why does wood have the construction industry buzzing? In addition to its design flexibility and environmental sustainability, the strength and stability of the engineered wood products used in MTF are expanding its use in commercial construction and changing public perception of the possibilities of wood.
Since 2013 in the continental United States alone, there are more than 700 construction projects for commercial, institutional, multi-use buildings that have either already been completed or are in the design phase, including high profile projects like the T3 office building in Minneapolis, Carbon 12 – a cross-laminated timber (CLT) luxury condominium complex in Portland, OR, and our project, Ascent residential tower in Milwaukee. Upon completion, Ascent will be the tallest wood frame structure in North America.
How is Mass Timber Different from Traditional Wood Construction?
First, when we talk about “traditional wood construction”, it’s important to make the distinction between heavy timber and light-frame construction.
Heavy timber construction is one of the oldest types of framing in the United States. Think about all the large, brick former warehouses that have recently been converted into upscale lofts and condominiums. Those rustic industrial beams renters love so much? That’s the “heavy timber” in heavy timber construction.
This type of construction involves a framework of heavy-sewn or laminated timbers. As you can tell from how many of those industrial-age brick warehouses remain, this type of construction is meant to stand the test of time. Both sound and largely fire-resistant, heavy timber construction is still included in the U.S. building code today.
Light-frame construction uses dimensional lumber or engineered wood to create its framework. Placed at specified intervals, it can evenly and efficiently distribute the load of the structure. Fast to build and economical, this type of construction is what you’d see in most residential and commercial builds.
The biggest drawback with these traditional types of wood construction is that neither heavy timber nor light-frame construction are structurally sufficient to build higher than 85 feet (or less than 6 stories).
Why the limit? Three things:
- Wood is combustible.
- People need to have enough time to get to safety in the event of a fire.
- More floors a building has, the more time is needed to evacuate.
While the size of beams, insulation and design can give occupants that much-needed time to evacuate, eventually, traditional wood structures will succumb and collapse. That’s not to say steel and concrete structures won’t do the same when exposed to prolonged fire and heat – it’s just that traditional wood structures will do so much sooner.
Isn’t mass timber also made of wood? Yes. Yes it is. But due to the way it’s engineered and treated (in particular CLT), it can maintain its structural integrity in the event of fire comparable to steel and concrete.
Why Mass Timber Construction?
Mass timber products such as cross-laminated timber (CLT) are becoming increasingly attractive to owners and developers for their aesthetic quality, structural performance, and opportunity for innovation. But the reasons for mass timber’s rising star don’t stop there.
- Sustainability:Mass timber offers a renewable and sustainable alternative to its more fossil-fuel intensive industry counterparts. Buildings constructed from wood become what researchers refer to as a “carbon sink”, in that they perform in much the same way that trees do in terms of their carbon engagement. Trees “inhale” CO2 as they grow and, chemically speaking, they lock that carbon away. The wood in a mass timber framed structure keeps that carbon sealed within itself until the wood degrades or the building is destroyed. According to a recent study published in the Journal of Sustainable Forestry, the substitution of steel and concrete with mass timber products in large-scale construction projects can reduce global CO2 emissions by as much as 31%.
- Market Uniqueness: By being left exposed, the wood beams, columns, and panels used in mass timber frame buildings provides a differentiating finish palette for a uniquely attractive aesthetic. Additionally, numerous studies focusing on wood’s biophilic benefits have found direct correlations between the use of exposed wood in commercial, residential, and medical-use structures and improved physical and psychological health and well-being among occupants who live and work in those buildings.
- Speed to Market and Cost Reduction: Mass timber framing systems can go up faster than other traditional material systems, with MTF projects able to be constructed approximately 25% faster than similar projects that use concrete and/or steel. Moreover, mass timber projects have seen as much as a 90% reduction in construction traffic – that is, in the number and frequency of industrial vehicles delivering materials – as well as up to 75% fewer workers, making for a much quieter and more efficient work site. All of this increased efficiency inevitably leads to a substantial overall project cost reduction and healthier bottom line for owners and developers.
How Catalyst Construction is Leading the Way
Catalyst Construction’s market-leading knowledge of and experience with mass timber has involved in-depth, comprehensive research of every national and international supplier in the mass timber market from Japan to North America in a knowledge procurement process that has made us the leader in MTF construction proficiency, competence, and know-how.
The team at Catalyst has properly and accurately vetted and priced various mass timber systems for a number of construction projects including the Timberlofts, Milwaukee’s very first mass timber building that opened in Spring of 2020, and The Ascent, a 25-story apartment tower that when finished will be the tallest timber building in North America.
In June of 2018, Catalyst Construction was selected by New Land Enterprises to provide preconstruction and construction services on The Ascent project and led the product selection process. Catalyst’s preconstruction team worked with Thornton Tomasetti and Korb Architecture to research, vet, and select the suppliers and erectors of Ascent’s mass timber frame. Upon its completion in 2021, the complex will include 265 apartments and a “wellness floor” that will feature a pool with fully operable windows, a sauna, steam room, and an entertainment center. The top floor will feature a resident amenity level with two outdoor decks, fire pits, grilling stations, a clubhouse, kitchen, and a co-working space.
Mass Timber Framing is a new and rapidly growing technology that offers unprecedented structural solutions and overall construction benefits that could potentially make steel and concrete construction systems obsolete. As an emerging technology, it is one with which people both inside and outside the industry do not have much familiarity.
While most construction firms in southeastern Wisconsin are just now getting to know this innovative new framing system, Catalyst Construction has been staying ahead of the curve by expanding its knowledge of the technology and methodology involved with mass timber. This knowledge, along with a network of product suppliers and the firm’s leadership on a growing list of mass timber projects, gives Catalyst an authoritative voice in the world of MTF systems, which means we can provide sound, trustworthy guidance at the critical initial design and selection phase of your construction project.