Mainebiz

V O L . X X I I N O. X X V I I N ine stories, 27 days, four workers and a crane. at's what it took to erect the structure for the 29-unit Murray Grove apartment com- plex in London using prefabricated solid timber for its weight-bearing walls and fl ooring. ere are no steel beams and only the ground story is concrete. e 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 struc- tural 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. e 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 lam- inated (NLT) and glue-laminated (glulam) timber have been identifi ed 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 million this year, largely due to closures at fi ve paper mills and two biomass plants in recent years. e council devoted most of its Sept. 19 annual meeting to several presentations about emerging markets for engineered wood products. Anthony istleton, a founding partner of London- based Waugh istleton 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 eff ort to fi nd new uses for Maine's vast forest resources. "We love wood and we've been pushing engineered timber for the last 12 years," says istleton, who was in Maine in October as the keynote speaker at the Wood Innovators Conference in Hiram. " e architecture of the 20 th century was defi ned by concrete and steel. We believe we're at the dawn of the timber age and that the 21 st century will be defi ned 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 con- struct ever-higher tall buildings around the world," says Shaler. "CLT is an opportunity that needs to be looked at in Maine." Proof of concept istleton's well-honed pitch for CLT as a viable build- ing 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. e Murray Grove project proved that point, he says, and has enabled the fi rm in later CLT projects to tell clients, "You can build it cheaper and you can build it quicker" and deliver on that promise. Environmentally, istleton says the fi rm tells clients that wood is a renewable resource that stores carbon, unlike steel and concrete that he says are mas- sive 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. e Murray Grove apartments, he says, were sold out before the build- ing was ready for occupancy. Ricky McLain, a University of Maine graduate who is technical director of WoodWorks, a Washington, D.C.-based organization off ering free project support for wood construction architects and builders, says internationally the height of CLT and engineered tim- ber projects is trending upward. Recent projects include an 18-story building in Vancouver and a 24-story build- ing in Vienna, both scheduled for completion in 2017. " e 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 benefi ts to those described by istleton. "Mass timber is a completely prefabricated structural framing sys- tem," he says. "So all of the fl oor plan systems, all of the columns, come to the site cut to length. Everything is laid out ahead of time. ink of having one panel cover 400 square feet at a time: You can really start to see some of the construction speed and effi ciency benefi ts that mass timber provides." P H O T O / JA M E S M C C A R T H Y Plywood on steroids Maine's forest products industry eyes emerging market for cross-laminated timber B y J a m e s M c C a r t h y N OV E M B E R 2 8 , 2 0 1 6 22 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.

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