How 'plywood on steroids' reduces construction time and payroll costs
Photo / James McCarthy
Anthony Thistleton, a founding partner of Waugh Thistleton Architects in London, touts CLT timber as a renewable resource that can be engineered for many architectural uses. He's designed a 10-story, 121-unit building, now under construction in East London, that uses engineered timber. He was keynote speaker at an October industry conference in Hiram.
Photo / James McCarthy
Russell Edgar, wood composites manager at UMaine’s Advanced Structures and Composites Center.
Nine stories, 27 days, four workers and a crane. That's what it took to erect the structure for the 29-unit Murray Grove apartment complex in London using prefabricated solid timber for its weight-bearing walls and flooring. There are no steel beams and only the ground story is concrete. The entire building was completed in 49 weeks, a time savings of 23 weeks compared to traditional steel beam and concrete construction.
At the time of its completion in 2009, Murray Grove was the tallest building in the world using solid slabs of cross-laminated timber for its structural framework. Similar to plywood, but built on a much larger scale, the CLT layers used in the project are made from solid 1-inch thick boards and cross-laminated into large slabs up to 30-feet long. The pre-fabricated panels included pre-cut openings for doors, windows, stairs and ducts, which greatly reduced construction times and related payroll costs.
Sometimes referred to as “plywood on steroids,” CLT and related engineered wood products such as nail laminated (NLT) and glue-laminated (glulam) timber have been identified by the Maine Forest Products Council as among the forest products with growing potential to boost the state's forest products industry, which saw its overall economic impact fall from $9.8 billion in 2014 to $8.5 billion this year, largely due to closures at five paper mills and two biomass plants in recent years.
The council devoted most of its Sept. 19 annual meeting to several presentations about emerging markets for engineered wood products.
Anthony Thistleton, a founding partner of London-based Waugh Thistleton Architects, designed Murray Grove and is now working on a 10-story, 121-unit CLT development in East London. He is a leading example of an architect using “mass timber” — a key element in the multi-pronged effort to find new uses for Maine's vast forest resources.
“We love wood and we've been pushing engineered timber for the last 12 years,” says Thistleton, who was in Maine in October as the keynote speaker at the Wood Innovators Conference in Hiram. “The architecture of the 20th century was defined by concrete and steel. We believe we're at the dawn of the timber age and that the 21st century will be defined by buildings made from the renewable resource of wood.”
Another proponent, Stephen Shaler, director of the University of Maine's School of Forest Resources, has brought together stakeholders to identify emerging markets for CLT and other engineered wood products.
“Cross-laminated timber is being used to construct ever-higher tall buildings around the world,” says Shaler. “CLT is an opportunity that needs to be looked at in Maine.”
Proof of concept
Thistleton's well-honed pitch for CLT as a viable building material tackles the cost question head-on. As a pre-engineered material, he says, CLT panels facilitate modular construction that can shave months off the production schedule. The Murray Grove project proved that point, he says, and has enabled the firm in later CLT projects to tell clients, “You can build it cheaper and you can build it quicker” and deliver on that promise.
Environmentally, Thistleton says the firm tells clients that wood is a renewable resource that stores carbon, unlike steel and concrete that he says are massive emitters of carbon dioxide and among the leading contributors to the world's greenhouse gas emissions.
“Not only is wood a beautiful natural material to work with, it transforms our relationship to the world,” he says, adding that their buildings' lower carbon footprint and natural ambience have proven to be strong selling points. The Murray Grove apartments, he says, were sold out before the building was ready for occupancy.
Ricky McLain, a University of Maine graduate who is technical director of WoodWorks, a Washington, D.C.-based organization offering free project support for wood construction architects and builders, says internationally the height of CLT and engineered timber projects is trending upward. Recent projects include an 18-story building in Vancouver and a 24-story building in Vienna, both scheduled for completion in 2017.
“The trending market for mass timber in the U.S. is that we're starting to see a push for taller wood buildings as well,” he said at the Maine Forest Products Council's annual meeting on Sept. 19.
McLain says that developers of CLT projects in the United States have seen similar onsite construction benefits to those described by Thistleton. “Mass timber is a completely prefabricated structural framing system,” he says. “So all of the floor plan systems, all of the columns, come to the site cut to length. Everything is laid out ahead of time. Think of having one panel cover 400 square feet at a time: You can really start to see some of the construction speed and efficiency benefits that mass timber provides.”
Only two CLT manufacturing plants in U.S.
The CLT used in Waugh Thistleton's projects is manufactured in Austria. There are only four CLT manufacturers in North America and only two in the United States — in Oregon and Montana.
Casey Malmquist, president and founder of SmartLam, Columbia Falls, Mont., came to Maine to speak at the Maine Forest Products Council's annual meeting, but also to check out possibilities for his company. “We look forward to the opportunity to take a look at the industry here and a potential location for a plant,” he says. “We actually are in the process of expanding and are doing some site-selection tours, so this fits nicely into that.”
Malmquist says in just three years the company has outgrown its 40,000-square-foot Montana facility, which produces up to 12 million to 15 million board feet per year of CLT products. It is evaluating options for a 120,000-square-foot expansion that would be capable of manufacturing 48 million board feet per year.
The yearly economic impact of making 48 million board feet? At the council's annual meeting Malmquist offered these metrics: Direct jobs, 264. Indirect jobs, 264. Worker wages, $21.6 million. Value of benefits, $2.16 million. Tax revenue, $6.27 million. The stored carbon and avoided greenhouse gas emissions resulting from 48 million board feet of CLT, he adds, equates to removing 20,620 cars from the road per year.
“Small logs, in our world, equate to big opportunities,” he says.
Why not Maine?
The obvious question for Maine, then, is why not locate a CLT manufacturing plant here — especially since more than half of the state's 17 million acres of forest are certified as sustainably managed, which can create opportunities for CLT buildings to receive Leadership in Energy and Environmental Design (LEED) credits.
UMaine's Shaler, who leads a CLT testing project funded by a $300,000 grant from the U.S. Department of Agriculture, says Maine has several strengths that could spur investors to locate a CLT manufacturing plant in the state.
Among them, numerous sawmills with established reputations for providing high-quality 2X timber that is used to make CLT columns, beams, walls and floors. The recent inclusion of Norway spruce by the American Lumber Standards Committee in the Spruce-Pine-Fir South grouping of wood species for home construction and industrial applications is another plus, he says, since it adds tonnage that could reduce costs for Maine-made CLT competing against regions where Norway spruce isn't as available. Add in proximity to East Coast markets and UMaine's world-class testing capabilities at its Advanced Structures and Composite Center, which already is being used by SmartLam and other CLT manufacturers to test their products.
Finally, Shaler adds, another advantage Maine offers is that most of its 17-plus million acres of forest is privately owned. “That increases certainty of supply,” he says.
“There is certainly a market that's growing for CLT [and other engineered wood products],” Shaler concludes, adding that if Maine can tap into that market it has the potential of becoming a major exporter of mass timber products.
“It will happen,” he says of general acceptance of CLT as a building material. “The question is when.”
Limited supply channel
If Maine succeeds in landing a mass timber manufacturer, it would reduce one of the impediments identified by Matt Tonello, a Portland-based project executive for Consigli Construction, an $800 million per year construction firm based in Milford, Mass. Consigli's clients include hospitals, colleges and general commercial enterprises.
The emerging track record for CLT being easier and faster to work with on modest-scale high-rise projects, as well as its environmental, puts it on his radar, noting it ranks favorably in six of nine criteria he applies to building materials.
“I would say I could make a pretty good argument CLT is equal to or better than steel or concrete in any one of these ways,” he says.
The downside?
“I can't buy CLT — anywhere in the Northeast, at least,” Tonello says. “I can't buy glulam easily, either. There are maybe one or two manufacturers up in New York.”
By comparison, Tonello says he can buy structural steel from 10 to 15 fabricators in the Northeast market and has numerous options for buying concrete as well.
There is, he says, a reluctance by design teams to be “early adopters.” There are also slightly higher material costs. While the latter can be mitigated by savings on construction time and labor, Tonello says cost is always an issue.
“It's very hard to convince a client to spend a single dollar more on their structure,” he says.
LEED construction offers a pathway to break into the marketplace, since it creates environmental incentives for a project using locally sourced materials manufactured within 500 miles of the construction site. Using Boston as the center, he says, that 500-mile circle extends over all but the northernmost tip of Maine but would include the Louisiana-Pacific plant in New Limerick. With New York City at the center, the circle only extends up into southern Maine.
“We can be competitive with the right design team, the right client and the right building type,” Tonello says. “It's a limited slice of the construction market right now.”
Bottom line? Tonello says Consigli remains interested in using CLT materials.
“We could pre-fabricate it, push it into some taller markets and with some labor savings and with some more flexible layouts and space planning I think it would be a huge market,” he says. “And I would love, personally, to see it as a product we could source here in Maine.”
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