When considering the biological properties of wood and mass timber, the mind first goes to the sensory properties of wood: its smell, texture, and unique grain, each as singular as a fingerprint. These properties also have consequences for the fabrication and supply chain of mass timber, necessitating digital fabrication, an equally digitized supply chain, and vertically integrated economies of scale.
Wood is the rare material that can be a carbon sink but is also endlessly millable and flexible in its structural tolerances. Mass timber—aggregated wood assemblies that combine multiple pieces of wood to radically increase their strength—is well-suited to prefabricated building and modular construction.
This is good news because, in its raw form, mass timber—and, in particular, cross-laminated timber (CLT)—is “not a commodity product,” says Ricky McLain of WoodWorks. “Depending on which manufacturer you’re working with, you could get any variety of wood species, which come with any variety of aesthetic and structural properties.” Digital fabrication is a way to standardize these disparate elements and express the material’s inherent flexibility.
“At its core, mass timber is by necessity an industrialized component,” McLain says. “We’re not making any of those larger components at the jobsite; those are all being prefabricated off-site. So understanding the supply chain is key. How is timber getting to the jobsite, and who’s putting it together on the job?”
Because of the relative newness of mass timber in North America and the lack of common standards, designers have to get intimately involved in the ways mass-timber manufacturers work.
“You’re not designing in a silo,” McLain says. “During design, you understand their capabilities and design your structure in a way that’s most efficient for their capabilities. There may be one manufacturer that produces a certain species that you just love the look of. Maybe another reason you’re using mass timber is because you need to fit a given column grid, so one particular manufacturer may work the best in that grid. So it’s working within that and choosing by advantages to help you select a manufacturer.”
As designers develop the ability to work concurrently with mass-timber manufacturers and integrate into the supply chain, their goal should become “to produce documents that can be directly translated into digitally actionable fabrication,” says Andy Ruff, a senior associate at Gray Organschi Architecture, resident at Autodesk Technology Centers, and research coordinator of the Timber City Research Initiative.
With mass timber, these elements can include structure, facade, insulation, and interior finish. “You can look at one material—one supplier—and create the majority of your building,” Ruff says. This material versatility increases the potential for vertical integration. Beyond potential ownership of the data created all along the proprietary chain, vertical integration offers the standard array of value-added efficiencies, as mass timber already generates an average schedule savings of 10%–25%.
For this reason, Ryan Smith, director of Washington State University’s School of Design and Construction, is seeing material suppliers moving into fabrication and manufacturing while general contractors are moving up and down the supply chain.
For manufacturers, the question becomes, “We are already manufacturing materials; why don’t we fabricate them, and why don’t we build with them?” Smith says. “Designers are working for developers, contractors, or the prefabrication company. By controlling design and even site assembly, the mass-timber fabricator has more control of the entire process of delivery. So I generally see a consolidation of companies that will happen, especially with COVID-19.”
“What’s going on right now in our space—not just in timber but in industrialized construction—you’re seeing a pressure in the industry,” says Amy Marks, head of Industrialized Construction Strategy and Evangelism at Autodesk.
“You’ve got big serial owners asking for things,” Marks continues. “You’ve got governments asking for things and requiring restarts with digitization and BIM and sustainability, especially around carbon. We’ve got ‘supersubs,’ subs that are taking over other trades. You’ve got big manufacturers that are taking advantage of some of these things. So when you add this kind of pressure on an ecosystem and you’ve got COVID-19 happening, the lines start to blur. So you start getting companies that have traditionally been very siloed in our ecosystem, where we’ve had to jump over chasms for information. A lot of these companies are turning into fab-integrated companies.”
Smith says that the average size of a US construction company is just eight employees, and the type of research and development needed to make mass-timber building technology widely viable doesn’t scale down to such a small operation. “There’s no ability to invest in R&D,” he says. “There’s no ability to gather data and really analyze and improve. When you start consolidating and aligning in vertical integration, you have the capital wherewithal to actually improve your processes on a daily basis.”
Mass timber allows incorporation of a wider array of material quality into supply chains. Because it’s milled into smaller articulated pieces, mass timber can make use of lower-quality wood, like pine trees killed by the beetle scourge that’s decimated forests across many millions of acres, which are currently fueling the relentless wildfires in the Western United States. That’s timber that would otherwise be a waste product or put to a far less valuable use than fodder for high-tech, carbon-positive construction.
Mass timber’s modularity and milling flexibility make it easy to disassemble and reuse. “We have the ability to not only initially machine wood but also re-machine and re-mill those timbers,” Ruff says. “It’s very difficult to reprocess concrete at the end of its life. Maybe if you want to make aggregate, but certainly it’s not maintaining that original component value. But we can simply back out screws and reuse panels wholesale.”
There are still intense gaps and challenges to the proliferation of mass timber in North America. Suppliers, manufacturers, and designers all need to draw more data from their workflows. The first mass-timber factory east of the Rockies opened just two years ago; for the industry to succeed, the reach and breadth of the supply chain must expand. Setting up new factories is capital intensive, and manufacturers will need more support from the private sector and tech industry.
“An even bigger constraint is the lack of building-industry professionals with experience successfully operating prefab factories that are able to integrate evolving industrial processes and technologies into their operations,” says Greg Howes, business development director at Cut My Timber, a mass-timber off-site fabricator and supplier.
Wood construction in North America is often associated with the typical timber-framed, pitched-roof suburban house. But these houses’ omnipresence doesn’t make up for their tendency toward low-quality, imprecise construction. “A big challenge ahead is to change the narrative around wood construction: that it can be a high-quality material, that it can meet a number of performance parameters,” says Smith, who is a founding partner of Mod X, a modular design and construction consultancy.
Smith says wood construction is a part of the design DNA of North America in ways that make it exceptional. In the United States and Canada, “90% of our built environment is wood,” he says. “That’s not the case around the world. Wood might make up 10% of the market in South America and in Asia.”
But in North America, wood is deeply tied into our sense of place and identity. “Our sense of smell, the sound of it, the touch of it—it’s biophilic,” Smith continues. “We have a history in this, and we have a supply chain in North America for this material. To make its way from lamstock all the way into value-added products and engineered-wood products—that’s an advantage. We actually understand the material at a level that many other countries don’t.”
This article was drawn from the Autodesk Technology Centers’ “Outsights: Design & Construction for Mass Timber” panel hosted by Sophia Zelov, Autodesk Technology Centers’ industry engagement manager for AEC, and moderated by Amy Marks, Autodesk head of industrialized construction strategy and evangelism.