LEVER Architecture is currently renovating the Oregon headquarters of The Nature Conservancy in East Portland. The Oregon Conservancy Center (OCC), as the building will be known, is on track to becoming one of the first structures in the country to utilize U.S.-manufactured cross-laminated timber (CLT) made from Forest Stewardship Council (FSC)–certified wood. Located at the corner of SE Belmont Street and SE 14th Avenue, the three-story structure will be revamped with an open-office space for the majority of its staff. LEVER will elevate the existing facade with a weathered steel rain-screen and high-performance glazing while building a one-story addition featuring mass timber. The newly built structure will house event space and a conference center, topped with a roof garden and an outdoor deck. The architects specified sustainably-sourced Oregon Juniper, CLT, and cedar from Oregon, Washington, and California in an effort to complement the Conservancy's commitment to energy efficiency and environmental stewardship. An array of photovoltaic panels will hover over the building and cover one-quarter of its energy use while a new variable refrigerant flow (VRF) system will assist in heat recovery. “We’re excited to be part of a project that embodies The Nature Conservancy’s commitment to protecting and restoring critical ecosystems,” said LEVER’s principal Thomas F. Robinson in a statement. “The design connects people and nature by integrating materials and landscapes that are specific to The Nature Conservancy’s priority projects around the state.” LEVER is working alongside Portland real estate developer Project^ to get the building off the ground. Project^’s vast portfolio includes the award-winning Framework, the first wood high-rise permitted in the country. Construction on the OCC started in March and is expected to be done in early 2019. The building is set to receive LEED V4 Gold certification.
Posts tagged with "Mass Timber":
The Center Party, a Swedish political party, has commissioned Anders Berensson Architects to design a speculative plan for a mass timber development in Stockholm. The design for the scheme was recently released without a timeline for execution. The development is a collection of towers and sky bridges built on top of the existing waterfront neighborhood of Masthamnen. The plan would leave the buildings below relatively untouched but would cap them with a public park and walkway level over which the new towers would rise. The designers embraced wood as a building material because it "releases the least carbon dioxide." Renderings show interiors and exteriors clad with wood finishes, and the architects describe the buildings using mass timber technologies like cross-laminated timber (CLT). The imaginative scheme is meant to provide additional housing close to the center of Stockholm, where the housing market is tight and space is expensive. There are no apparent plans to enact the proposal. The Center Party has worked with Berensson before on speculative designs for the city, many of which have included timber high-rises. The party has relatively little power to realize these ideas as they are the opposition party in the city's government, which is controlled by the Social Democrats. Timber has received a lot of attention in Sweden as a structural material for high-rises, although it's not clear what the country has been able to realize so far. Globally, mass timber is starting to make inroads as a standard building technique, but it faces a long road to widespread adoption in the U.S.
Thanks to a recent addendum to Oregon’s building code, the state is the first in the country to allow timber buildings to rise higher than six stories without special consideration. Portland has become something of a hotbed for timber innovation as of late. Carbon12, PATH Architecture’s eight-story glulam and cross-laminated timber (CLT) tower with a steel core, recently became the country’s tallest timber building and was set to be surpassed by LEVER Architecture’s 12-story Framework. Alas, that project was put on hold due to mounting financial difficulties last month, but it seems the precedent that the project achieved in securing a building permit from the State of Oregon and City of Portland will live on. The timber allowance comes courtesy of Oregon’s statewide alternate method (SAM), a state-specific program that allows for alternate building techniques to be used after an advisory council has approved the “technical and scientific facts of the proposed alternate method.” The allowance comes after the International Code Council (ICC)–the nonprofit group that Oregon models its building codes after–established the ICC Ad Hoc Committee on Tall Wood Buildings in 2015 to explore the benefits and challenges of using timber in tall buildings. A Committee Action Hearing was held in April of this year, where the Ad Hoc Committee, made up of code experts, stakeholders, and industry members presented their findings. All 14 of the committee’s suggestions were adopted, introducing standards and best practices for fireproofing, the load-bearing potential of CLT and heavy timber, water resistance, sealing, seismic ratings, and more. Three new building classifications were introduced as a result: Type IV A, timber buildings permitted up to 18 stories and 270 feet tall, Type IV B, timber buildings with a maximum height of 12 stories and 180 feet, and Type IV C, which is permitted to rise nine stories and 85 feet tall at maximum. The shortest of the timber typologies is allowed to use exposed structural timber as an interior finish, whereas the tallest, type A, must enclose all exposed surfaces and include a three-hour fire-resistance rating for the structural elements. “We congratulate the State of Oregon on becoming the first state to provide building code recognition for construction of tall, mass timber buildings,” said American Wood Council President & CEO Robert Glowinski in a statement. “Mass timber is a new category of wood products that will revolutionize how America builds and we’ve seen interest in it continue to grow over the last several years. This action by the Codes Division Administrator helps code officials in Oregon by making provisions consistent throughout the state. In adopting this new method, Oregon has also recognized the significant environmental benefits that accrue from greater wood product use.”
Last November, the U.S. Department of Commerce under President Trump announced an average of 21 percent import duties on Canadian timber products entering the U.S. The announcement was greeted with mixed reactions within the construction industry; builders claimed that the tariffs would increase the cost of construction, and American suppliers argued that the domestic timber industry would benefit, expand, and keep wood prices low. Single-family home construction in the U.S. relies heavily on Canadian softwood for roofing and framing. In 2017, Canadian lumber yards supplied 28 percent of the U.S. softwood lumber market, and home builders have been the first to raise concerns about the new duties, which were in effect by January. The National Association of Home Builders (NAHB) claims that the imposed tariffs have added approximately $9,000 to the cost of single-family homes and up to $3,000 on multi-family homes. The NAHB doesn’t believe U.S. domestic production is capable of meeting the current market demand and that the tariffs only hurt native manufactures by forcing them to increase their lumber prices. The NAHB is calling for the Trump administration to resume talks with Canada to secure a more mutually beneficial long-term agreement. David Logan, director of tax and trade policy analysis at the NAHB, says that historically, the U.S. lumber field has never been able to support rapid housing growth. “Buyers are still buying from the distributors they’ve always sourced from despite the tariffs,” he said. “Domestic lumber production has increased marginally in the last year, but it’s not kept up with the housing demand in terms of percentages, so it’s hard to say that we’re meeting the challenge. This has always been the case. We can’t meet that need...not even close.” Logan also argued that larger lumber companies in the U.S. are profiting unfairly from the deal, citing the Seattle-based Weyerhaeuser, which owns 12.4 million acres of forest in the U.S. alone and manages 14 million acres in Canada, as well as West Fraser, a Vancouver-based company that operates 48 mills across both countries. The NAHB claims that these companies are able to reap the benefits of both markets under the current trade agreement and likely won’t be affected if things change again. “We say over and over again that we need predictable and stable supply. That means using Canadian lumber,” Logan said. “Diversification of operations in the biggest mills on both sides of the border has really hampered any progress towards talking further about this issue because they’re able to increase production and do well. Prices have been so high there’s not really room for anyone but the big players to have a seat at the table, whether they’re Canadian or American.” The U.S. Lumber Coalition (USLC) rejects these claims. “Since the duties were implemented," the USLC wrote in a statement last week, "U.S. lumber shipments have increased by about 1.4 billion board feet, roughly filling the gap left by the decrease of Canadian imports. U.S. companies continue to invest in expanding their production capabilities to mill lumber from American trees by American workers to build American homes.” Pleasant River Lumber, a small milling company based in Maine, isn’t experiencing the negative side effects that the NAHB claims is coming out of the current tariffs on timber. In fact, the company is on track to complete a $20 million expansion at two of its four sawmills in the next 18 months. As part of the USLC, Pleasant River Lumber sources 95 percent of its lumber within the state of Maine and takes a bit from New Hampshire and Canada as well. Owner Jason Brochu is pleased with the country’s newfound focus on local production and plans to take advantage of it. “Increased demand due to forest fires and hurricanes in other states, spiked prices from the duties, heightened transportation costs, and a strong housing market all factor in to establish a level playing field for lumber production in the U.S. right now,” said Brochu. “We can’t compete against the government or any larger mills without things being equal.” Pleasant River Lumber is capitalizing on the growing lumber market by adding 50 percent more capacity to its production facilities and hiring 40 new employees as quickly as possible. They plan to boost production of their dimensional lumber from 200 million to 300 million board feet annually with the upgraded equipment. More importantly, they’re investing in their framing mills to address the increased demand within the housing market. “We believe we’re pretty typical of most mills in the country at this time,” Brochu said. “Most mills in Maine specifically are adding shifts or putting more money into mills to increase volume. We’re confident that the duties protect our rights as producers in the U.S. and we feel like the laws are working the way they should.” Brochu also emphasized how “relatively insignificant” framing lumber is in housing construction. USLC said the same thing stating that lumber makes up only 2 percent of the cost of a new home—which in 2018 stands at $368,500. Framing lumber isn’t the only wood material that’s used to construct new homes. Plywood, which has zero duties imposed on it, flooring, and other timber products are also increasing in price. New York-based specialty wood-product manufacturer Hudson Company said the niche wood market has been affected as well. Two of its most popular reclaimed-wood products, both of which feature Canadian imported lumber, have both been impacted dramatically, says owner Jamie Hammel. Sales of silver pine siding are down by 60 percent, while hand-hewn beams are down 40 percent. “The reason our business is not down by 60 percent,” he said, “is because we sell other things. But we've had to limit the amount of volume we import because of the tariffs and we’ve had to diversify our product line to adjust and will continue to do. We’ve had to source more products locally which I guess was the administration’s goal.” The timber tariffs against Canada were among the first official duties placed on another country by the U.S. government since Trump took office. In the ten years since the Softwood Lumber Agreement (SLA) was established in 2006, the U.S. Commerce Department has allowed Canadian companies to sell lumber to the U.S. market at subsidized prices, lifting previously countervailing and anti-dumping duties as long as prices stayed above a certain figure. The SLA expired in 2015 and since then both countries have been unable to negotiate a new deal. On behalf of the NAHB, Logan said that his organization doesn't foresee a new Canada-U.S. deal happening in the near future. “We don’t think the dialogue will reopen any time soon as long as the North American Free Trade Agreement negotiations are ongoing. If history repeats itself...the last time this happened it took around 5 years to settle,” he said referring to the original SLA. “Hopefully I’m wrong and this is done very quickly. Until then, prices will maybe get a bit higher, but volatility will certainly increase.”
Unicorn design/build company Katerra is continuing its impressive expansion from start-up to $3 billion tech-and-construction giant with the recent acquisition of Vancouver’s Michael Green Architecture (MGA). The Canadian architecture studio is known for pushing the boundaries of timber construction (including some of the largest mass timber buildings in the U.S.), and Katerra reportedly wants to use their expertise to bring down construction costs as well as better understand the material. The key to Katerra’s success lies in its vertically integrated business model; the company moves its projects through a single pipeline and handles everything from design, to engineering, to construction, using prefabricated modules to standardize the process. With $1.3 billion in projects under various stages of development–many of which are already framed with mass timber–the company is constantly searching for ways to optimize its production. Before acquiring MGA, Katerra was already hard at work building out their 250,000-square-foot cross-laminated timber (CLT) panel factory in Spokane, Washington. MGA had been an early adopter in the mass timber construction game, and the firm, jointly based in Portland, Oregon, as well as British Columbia, has continued to push timber towers taller. Joining Katerra, was for the 25-person studio, a natural progression according to founder Michael Green. It also happens to align the weight and financing of a major Silicon Valley player behind the studio. “Two values convinced me to join with Katerra,” Green told Vancouver magazine, “addressing our impact on the climate and making good architecture affordable. This acquisition gives us the opportunity to address both of those issues at scale.” Through the use of mass customization (using a kit of parts to design distinct buildings instead of a “one size fits all” modular approach) and mass timber, Katerra is hoping to lower its construction costs by up to 30 percent. While land prices are typically the largest slice of the development cost pie, Katerra is bringing down both its material as well as labor costs. But the choice was about more than that, according to Katerra's head of architecture, Craig Curtis. In order for the company to continue expanding, it would need to bring aboard more design talent, and MGA has had experience with timber buildings of all scales. On MGA's side, Katerra won't be fully consuming their practice, and the firm will still handle a stable of its own projects independently.
With a mix of recently-enacted and forthcoming legislation, Washington State is beginning to embrace mass timber construction. Washington State Governor Jay Inslee recently signed legislation for State Bill 5450, a new law that directs the state’s building code council to “adopt rules for the use of mass timber products for residential and commercial building construction.” The law will allow state and local jurisdictions to begin to work mass timber construction into local building and zoning codes, a first step toward the wider adoption of the construction technology. The law includes the requirement that rules adopted for the use of mass timber products by the state building code council “must consider applicable national and international standards,” a nod to the forthcoming changes to the International Building Code (IBC) that would institute new guidelines for mass timber structures rising as high as 18 stories. The proposed changes are currently under consideration by IBC’s Ad Hoc Committee on Tall Wood Buildings, which was established in 2016. The committee will begin collecting public comments on the proposed changes in April of this year. In a more aggressive move, the Washington State Legislature is also working toward enacting State Bill 5379 (SB 5379), a measure that would require all public buildings in the state rising 12 stories or less be built using Cross-Laminated Timber (CLT). The move is a natural one for Washington, which has a thriving timber industry and has some catching up to do in terms of mass timber adoption when compared to neighboring Oregon. According to the Washington State Department of Commerce, the timber industry brings in over $28 billion in sales annually across the state and employs over 105,000 workers garnering over $5 billion in wages. The potential law would make the state the first in the country requiring mass timber construction. Currently, SB 5379 is only in committee at the moment and a timeline for passage and enactment has not been released.
If California’s gubernatorial candidates are to fulfill their ambituous goal of adding up to 3.5 million new housing units across the state over the next eight years, new efforts will need to be undertaken to streamline and reform the state’s sagging construction industry—Could this effort create an opening for mass timber construction to take hold in the Golden State? It might, and here are a few reasons why. For one, there’s a growing push for new urban housing in California that could soon make the mid-rise apartment the state’s quintessential dwelling type. There’s strong reason to believe that if proposed regulatory changes go as planned, cities in the state could see a flowering of the kinds of four- to eight-story multi-family structures mass timber excels at delivering. With construction times running 15 to 20 percent faster than conventional building, there’s a potential mass timber technologies could help bring new units online very quickly, especially if minimum dwelling standards are set and municipalities streamline permitting and approval. Secondly, mass timber is becoming more widely-accepted as a building approach, reflecting a growing awareness of its inherent structural and fire-safety benefits. The nascent industry is cheering recent changes to the 2021 version of the International Building Code that will allow mass timber construction for structures up to 18-stories high. The shift could bring down the cost of building dense housing in the medium-sized city centers—downtown Long Beach, Glendale, San Diego, San Jose, and Oakland, for example—where lots of growth could happen but has so far been lacking. At these heights, it’s possible mass timber buildings could be more affordable to build than conventional structures while still delivering the height and structural resilience formerly only possible through concrete and steel frame construction. With San Francisco and L.A. building out larger transit systems and the state’s high-speed trail line on the way, it will be important to add high density nodes throughout the state to meet climate and housing goals. Cory Scrivner, a mass timber specialist with Structurlam, explained via email that with the coming changes to IBC and looming reforms to local zoning, “The market for mass timber will be growing significantly over the next few years.” With disruptive and new tariffs on foreign-grown softwood and imported steel and aluminum, its possible there could be further financial incentives to build structures made from regionally-grown timber, as well. Katerra, a Menlo Park, California-based construction technology and services start-up, is busy constructing a 250,000-square-foot factory in Spokane, Washington where it will produce mass timber products including cross laminated timber (CLT) panels. The company, which seeks to bring many aspects of the construction process—design, engineering, materials, manufacturing, and assembly—under one name while also modernizing the construction trades, is well-poised to play a role in California’s housing recovery. The company—which already has a functioning factory in Arizona—is growing, having just received a boost of $865 million in investment capital as it seeks to build out its network of regional manufacturing facilities Furthermore, because mass timber manufacturing is typically performed indoors with fewer workers and in advance of job site installation, mass timber construction also potentially holds the promise of side-stepping the state’s vexing shortage of skilled construction workers, one of the many unsolved structural repercussions of the Great Recession. According to Craig Curtis, president of Katerra’s architecture unit, the company’s factory-focused business model means that fewer—and differently-trained—workers are required on site. Instead of hammering nail to wood on a desolate job site, Katerra’s equipment operators and workers produce interior and exterior wall panels, roof truss assemblies, floor systems and countertops, among other building components in a factory. On-site, a crane and a well-trained team of workers assemble each new building in a fraction of the time compared to normative building practices. Curtis said over telephone, “[Addressing California’s housing crisis] is exactly the type of problem we are trying to solve—everyone deserves to live in a well-designed home delivered at an affordable price point.” And lastly, because each mass timber assembly is made to order, the so-called “mass-customization” potential of mass timber construction could also be a boon for the urban character of cities and residents alike, potentially resulting in a rich variety of building approaches and unit types. Might this variable approach even do away with the dreaded “stucco box?” Only time will tell. California’s housing shortage is a watershed event several generations in the making that will require proportional measures if it is to be adequately addressed. Given current understanding of what the mass timber industry is capable of producing, a rising wave of zoning reform, and growing funding sources for affordable housing construction, it might be time for municipalities and developers alike to take a look at this new building technology.
Half a million square feet of mass timber office space is coming to downtown Newark, New Jersey, thanks to international firm Michael Green Architecture (MGA) and New York–based developer Lotus Equity Group. Lotus has described the project as the largest timber office building in the United States, and the tower will anchor Riverfront Square, a massive 11.8-acre, mixed-use development in Newark’s Central Business District. The building itself will forgo the typical steel and concrete core, instead using cross-laminated timber (CLT) beams and panels, and rise from a concrete foundation. Most of the project’s space seems horizontally aligned, as the building is composed of three stepped volumes that top out with the 11-story tower. This makes sense, as mass timber high-rises are still a touchy regulatory topic; the Wall Street Journal notes that the tallest timber building previously approved in New Jersey was only six stories tall. While the core, slabs, and wall panels will all be made from wood, the facade of the building will likely be clad in brick, metal paneling, or more wood. The structural elements will remain exposed throughout the interior and create a warm, welcoming environment inside. Outdoors, employees will be able to make use of several roof decks and related amenities. “Good buildings are good neighbors and we envision a sustainable, efficient and architecturally-stunning future for Newark,” said Michael Green, founder and principal of Michael Green Architecture, in a press release sent to The Architect's Newspaper (AN). MGA is no stranger to timber construction, as 95 percent of the studio’s projects are in wood. Part of their commitment is driven by environmental concerns, as concrete and steel production accounts for 10 percent of greenhouse gas emissions worldwide. Conversely, timber buildings sequester carbon dioxide in the wood and can reduce a project’s environmental footprint. The development of Riverfront Square is being led a number of high-profile architecture firms, including TEN Arquitectos, Practice for Architecture and Urbanism, Minno & Wasko Architects and Planners, and MGA. Once completed, Riverfront Square should bring up to 2,000 residential apartments, 2 million square feet of Class A office space, 100,000 square feet of retail, 185,000 square feet of hotel space, 31 maker spaces, and a 30,000-square-foot arts and cultural area to downtown Newark. The drive to attract tech talent to Newark is likely motivated in part by Amazon’s search for a city to build their second headquarters in; Newark made the 20-city shortlist released last month, after promising $7 billion in tax incentives to the tech giant.
The Architectural League of New York’s Emerging Voices award and lecture series highlights individuals and firms with distinct design “voices”, singling out those with the potential to go on to even greater heights. 2018 saw two rounds of judging; first by a panel of past Emerging Voices winners, and a second to pick the winners. The first-round jury included Virginia San Fratello, Sebastian Schmaling, Wonne Ickx, Lola Sheppard, Marcelo Spina, Carlos Jimenez, and Marlon Blackwell, as well as members of the second-round jury, Sunil Bald, Lisa Gray, Stella Betts, Jing Liu, Paul Makovsky, Tom Phifer, Chris Reed, and Billie Tsien. AN profiled all of the emerging voices firms in our February print issue. Modus Studio founder Chris Baribeau will deliver his lecture on March 1st, 2018, at the SVA Theatre in Manhattan. Modus Studio might have started in 2008 as a two-man operation in cofounder Chris Baribeau’s back office, but the firm’s expansion to 24 people and a full fabrication shop shouldn’t have come as a surprise. The office’s intensive focus on the surrounding Arkansas environment and their hands-on approach have drawn attention both inside and outside of the state. “A thinking–making philosophy really evolved out of our passions, from working through college, working on construction, working on fabrication,” explained Baribeau. “It set the tone for the rest of our professional work.” Modus is a frequent collaborator with the University of Arkansas and has designed for the school a pair of mass timber residence halls, an athletic area master plan, and, most recently, a sculpture studio— although the firm has realized nearly every type of project. Its single-family homes typically draw on the surrounding geographies and ecosystems to influence the final forms, as is the case with Van Huset on the Bluff, a stark cabin overlooking Beaver Lake, in northwest Arkansas. Educational work has a special place in the studio’s canon. Green Forest Middle School, Modus’s first project, was also the first school that either Baribeau or cofounder Josh Siebert had ever worked on. Having to leap into a new building typology meant engaging heavily with the community at every step of the school’s design and construction, an approach that has carried over to all of their projects afterward. Timber and sustainability are prominent through-lines in many of Modus’s built works, no matter the intended use. Working with timber allows the studio to harvest wood directly from the trees on-site, or if they’re not able to do so, connect with Arkansas’s timber industry. Even Modus’s Fayetteville office, a reclaimed warehouse clad in timber that was charred in the fabrication shop, is winning notice, as it was Arkansas’s only LEED Platinum– certified building in 2017. “We’re very connected to the natural world,” said Baribeau. “And being in the Ozarks, the language of the rugged mountains and valleys and rivers connects us to the outdoor world. We’re straddling this dynamic place that’s somewhere between the manmade and the natural world. Our buildings are about fitting into the landscape and drawing inspiration from the context around the site.” Modus views its location outside of the “major design cities” as a boon. Arkansas is in the process of rebuilding and infilling its urban centers, providing the studio an opportunity to experiment while allowing them to build their brand through projects that serve the community. While Modus has begun working on projects as far north as Illinois, Baribeau is most proud of the K–12 schools that the studio has designed for low-income, rural areas. “We’ve found, particularly in this region of Arkansas, how rural communities are really underserved in terms of good design. The hub of that community, their tax money, the local football team, all focuses around the public school. For us, the ongoing tilling of the soil is to raise the bar for rural communities."
The University of Idaho (UI) in Moscow, Idaho, has partnered with the state’s timber industry, and Portland-based Opsis Architecture, to construct their newest multi-use basketball arena out of mass timber. The Idaho Central Credit Union (ICCU) recently purchased the naming rights for the arena for $10 million, meaning the arena is now well on its way to breaking ground, with $34 million of the needed $45 million accounted for. With a 4,200-seat basketball court, practice court, offices, locker rooms, conference spaces for both the men and women’s basketball programs, and volleyball courts, university officials have expressed hope that the arena would jumpstart athletic fundraising, as well as architectural and engineering interest in the school. In addition to the sports facilities, the 70,000-square-foot space will double as convention space and also be used to alleviate overcrowding in other buildings on campus. Designed to showcase the massive curvilinear roof that drapes itself over the building, Opsis has chosen to leave the structural timber elements exposed throughout the project. V-shaped timber columns are on prominent display above the entrance, while the underside of the roof features a curving lattice of wooden beams that’s visible from everywhere in the building. Light wood finishes have been used in the few interior areas where the structural elements are hidden, and the building’s exterior will be clad in metal paneling. If completed, the ICCU Arena will be the largest mass timber arena in the country, and the ICCU would retain naming rights for the next 35 years. Opsis is shooting for a LEED Silver certification or higher. The national firm Hastings + Chivetta has signed on as the interior architect / Sports planner, and KPFF are the consulting structural engineers. Assuming fundraising continues at the same pace, UI officials expect construction to complete in 2020, and possibly as soon as 2019. The accelerated timetable makes sense considering the advantages in construction speed that mass timber provides, especially as the materials would be locally sourced.
If the steady stream of newly announced mass wood projects is any indication, mass timber building technologies are poised to take the American construction and design industries by storm over the next few years. As products like cross-laminated timber (CLT), nail-laminated timber (NLT), glue-laminated timber (glulam), and dowel-laminated timber (DLT) begin to make their way into widespread use, designers, engineers, and builders alike are searching for the best—and sometimes, most extreme—applications for mass timber technologies. But rather than reinvent the wheel, American designers can look to experienced mass timber designers in Europe and Canada for key lessons as they begin to test the limits of these materials in the United States. European and Canadian architects and researchers have long been at the forefront of mass timber design, starting with early experiments in the 1970s. By the 1990s, researchers like Julius K. Natterer at the Federal Institute of Technology in Lausanne, Switzerland, were developing initial CLT prototypes. Natterer’s work has been buttressed by that of many others, including research performed at the Norwegian Institute of Wood Technology under Thomas Orskaug and experiments conducted at the Technical University of Munich under Stefan Winter. One key lesson European timber projects teach is that when it comes to structural systems, weight matters. On average, mass timber assemblies weigh between one-third and one-fifth as much as concrete structures, despite equivalent structural capacities. As a result, mass timber buildings are much lighter than concrete ones, a positive for building in tricky urban situations, for example—where underground rail yards, subway tunnels, and municipal utilities place limits on how heavy and tall buildings can be. London-based Waugh Thistleton Architects (WTA), for example, recently completed work on Dalston Lane, a 121-unit CLT midrise complex located above a tunnel serving the Eurostar train line in the city’s Hackney neighborhood. For the project, the architects worked with timber-engineering specialists Ramboll to develop a stepped tower cluster rising between five and ten stories tall. CLT panels are used for the external, party, and core walls of the building, as well as the stairs and the building’s floors. The variegated massing is due directly to the architect’s use of CLT construction, which resulted in a lighter building that allowed the designers to build taller without more extensive foundations. The resulting building, with its staggered massing, better maximizes daylight infiltration into apartment units. The added height allowed the architects to add 50 more units to the project than originally permitted, a testament to just how light CLT can be. Andrew Waugh of WTA said, “Timber buildings are just simpler, cheaper, and nicer [than concrete ones]. High-density urban housing should be built using mass timber.” Lighter mass timber buildings also perform better in seismic zones. Since the lighter buildings carry less inertia, the potential for catastrophic swaying goes down. The strategy was applied this year with the Brock Commons tower, an 18-story, 400-bed college dormitory designed by Vancouver-based Acton Ostry Architects for the University of British Columbia Point Grey campus. The tower is made up of a hybrid structural system that includes CLT floor slabs, glulam columns, steel connectors, and dual concrete cores. The concrete cores anchor the light mass wood structure in place, helping to counteract seismic and wind-generated forces. The 173-foot-tall structure is currently considered the tallest mass timber building in the world, and the construction is particularly multifaceted, utilizing a specifically fabricated set of interdependent building materials and finishes to meet structural and fire-safety regulations. The Brock Commons tower’s hybrid structural system brings to light another valuable lesson: that above certain heights—ten to twelve stories—the lightness of mass timber construction becomes a liability with regard to wind loads. The lack of physical mass at the highest parts of a prototypical timber tower results in increased deflection from wind loads. Ola Jonsson, partner architect at Swedish architecture firm C.F. Møller, recommended architects “go back to thinking about construction when designing mass timber structures,” as a way of rethinking approaches to dealing with difficult-to-manage structural conditions. He added, “It’s so early [in the adoption of mass timber technologies] that few really know how to do it well.” The architect said that with certain tall timber tower projects the office is working on, designers had to develop new massing strategies to limit wind loads. Jonsson continued, “Many engineers lack experience in mass timber, so architects have to become central figures in construction and design during this early phase of adoption.” The firm is currently developing over ten mass timber projects, an emerging body of work that came out of earlier mass timber competition entries developed by C.F. Møller that took the world by storm. C.F. Møller recently entered into a partnership with HSB Stockholm—Sweden’s largest housing association—to design a series of new mass timber housing towers, including the 34-story Västerbroplan tower designed with concrete cores and wraparound terraces. The tower’s columns and beams will consist of a blend of CLT and solid timber. The building’s terraces will come with integrated exterior curtains and will be fully enclosed by a steel superstructure containing glass panels. The tip of the building is designed to dematerialize as it steps back along two facades, creating a series of exposed terraces and planted areas. Like Brock Commons, Västerbroplan tower features a hybrid structural system that is “resource-effective,” according to Jonsson, meaning both lightweight and rigid. The firm is also at work on a 20-story bundled housing tower called Hagastaden for HSB Stockholm, this one designed as part of a new quarter of the city that will contain mixed uses and generous pedestrian areas. The tower features varied floor heights designed to accommodate divergent uses like student flats, penthouse apartments, and typical family-occupied units. Aside from the firm’s multiple mass timber projects, C.F. Møller is working as part of an interdisciplinary research team that is developing new strategies around mass timber towers rising 20 stories or more. The group—backed by SP Technical Research Institute of Sweden, Växjö Municipality, and Linnaeus University, among others—will investigate mass timber construction from a fire-safety, life cycle, and construction technology perspective. Regarding the research project, Jonsson explained, "Massive wood constructions give urban planners, architects, and designers great possibilities to develop innovative and sustainable architecture,” adding, "but a broader knowledge and more practical experience in the industry is needed." Another paradigm-shifting impact mass timber construction has had on European building methods relates directly to the construction process. Because mass timber elements are factory-produced to order, the relationship between engineer, builder, and architect is extremely integrated. Cory Scrivner, mass timber specialist with Canadian mass timber manufacturer Structurlam, said, “For us, it’s all about the 3-D model. [Digital modeling and coordination] are all done before we go into production in the factory: Everything has already been approved by the architect, engineer, and our team.” Scrivner explained further that the intense coordination was necessary, as “we are designing a building made from components that are accurate within one to two millimeters of the digital model.” The designers behind Brock Commons utilized Structurlam as the mass timber manufacturer for the project. The advanced level of project coordination and off-site fabrication meant that project was finished roughly four months ahead of schedule, with a time-lapse video on a project website showing construction crews erecting upward of two floors per day. The first story for the project was built from cast-in-place concrete, while the remaining 17 stories are built in mass wood. The structural system utilizes glulam columns, steel connectors, and a two-way spanning CLT flat-slab. The design creates a floor beam–free structure that could be erected start-to-finish in nine and a half weeks. The rapid-fire construction time line, however, comes at the expense of longer planning and design phases prior to any work boots hitting the job site, as the teams must become absolutely synced prior to fabrication. Waugh of WTA explained that often with timber buildings, the firm asks its clients to “give us more time now [in the planning stages of construction] and we’ll save you even more time on the back end.” Waugh added, “The better programmed the construction process, the faster and more accurately the buildings come out.” Waugh said that after erecting several mass timber structures, the firm had “gotten so much better at it” than when they first started. One area of improvement has been material usage, which decreased with each project as the structural capabilities of mass timber have been further explored, tested, and certified. The Dalston Station project mentioned earlier, for example, utilized about two-thirds as much timber as the firm’s first mass timber project erected a decade ago. Part of the reason for the improvements, Waugh and Jonsson agreed, results from designers’ greater awareness of and comfort with the construction process. “To design well in mass timber, you need an architect who wants to understand that the nature of [the architect] is one of a ‘master builder’ as well as one of a ‘master designer,’” Waugh explained. Since mass timber construction methodologies are based on kit-of-parts assembly systems of mass-produced panel types and structural elements, there has been increased interest among European and Canadian firms in building high-density mass timber housing. These experiments have positive implications for the many American cities burdened with housing shortages and long project-approval times. Waugh explained that WTA’s focus rests on expanding the abundance of available housing through mass timber construction. He said, “We design everything in our office now as if it was a mass timber project. Concrete projects are becoming more and more rare.” Several projects in the works, like Shigeru Ban’s recently proposed 19-story Terrace House in Vancouver, Michael Green Architecture’s 35-story Baobab building in Paris, and PLP Architecture’s 80-story addition to the Barbican housing estate in London, point toward a wider adoption of tall and supertall mass timber housing towers. With faster construction times and fabrication that can occur in tandem with permitting, mass timber has the potential to help cities add housing rapidly, safely, and efficiently. Waugh added, “Humanity is becoming more urban, so the principal job of an architect in the 21st century is to develop high-density urban housing. In an era of climate change, it behooves you [as a designer] to reduce the amount of carbon emitted. Again, for us, mass timber is a way to do that.”
Michael Green Architecture (MGA) is a leader in the design of mass timber structures. The firm, jointly based in Portland, Oregon, and British Columbia, Canada, has been a pioneer in mass timber construction since the early days of glulam. Now, as mass timber technologies proliferate and gain wider acceptance, MGA is poised to make the next great leap in mass timber construction: full-fledged mass timber automation and prefabrication. “All of our projects are made from wood,” Michael Green explained over telephone, before adding that 95 percent of the firm’s work is specifically built using mass timber. The approach is due mostly to preference, as Green is a trained millworker who began his career decades ago working for renowned architect César Pelli designing “big buildings in steel and concrete around the world.” Those whirlwind experiences left the architect starved for ways to reengage with natural materials and craft, so after returning to his native Canada, Green opened his own wood-focused office. Throughout the early mass timber era, the architect was among the first to consider its widespread use and architectural potential. Today, the office focuses on utilizing mass timber elements in a variety of building types—for example, when tight urban conditions call for compact and efficient structures. The firm also works with institutional clients seeking long-term facilities and “100-year” buildings, which mass timber can easily provide. Green sees working in mass timber as “an opportunity to insert a lot of passion” into building projects that work as explorations in industrial design and are planned with a keen understanding of how they will be put together. This industrialized construction process suits Green, who explained that construction remains the last “major industry left on Earth that is still craft-oriented,” meaning that every building is built essentially as a one-off, custom prototype with none of the cost-saving benefits of industrialized factory production. That’s where mass timber comes in—building components are produced to order in controlled factory settings, where weather, temperature, and other variables are tightly relegated. The firm is currently working with technology start-up Katerra, which is looking to utilize the potentials of mass timber to automate and integrate the construction process nationwide. Wood Innovation and Design Centre MGA recently completed work on the Wood Innovation and Design Centre in Prince George, British Columbia. At the time of its completion, the nearly 97-foot-tall, six-story structure was the tallest all-timber structure in the world. The lower three floors of the project contain facilities for students pursuing wood-focused engineering degrees while the upper floors house governmental and wood industry–related office spaces. The building is clad in an elaborate system of louvered wood shutters that are optimized by exposure to mitigate solar glare. Aside from the structure’s mechanical penthouse, there is no concrete used in the building. Instead, the “dry” structure integrates CLT floor panels, glulam columns and beams, and mass timber walls into a complex design that conceals electrical and plumbing services within its relatively thin floor panels. North Vancouver City Hall The renovation and expansion of a municipal City Hall structure in North Vancouver, British Columbia, is one of the firm’s earliest mass timber projects. The 36,000-square-foot renovation bridges a repurposed 1970s-era structure and an existing library building with a new double-height mass timber and glass atrium. The 220-foot-long space is topped with CLT roof joists propped up on large CLT columns. Where the atrium meets the existing offices, clerestory windows provide views between public and business areas. The exterior of the long and narrow addition is clad in charred wood—a material that also wraps the exterior surfaces of other building elements—creating a new and dramatic exterior courtyard. Empire State of Wood As part of MGA’s early mass wood experiments, the firm worked with Finnish wood and paper group Metsä Wood on their speculative wood initiative. For the project, the firm was tasked with redesigning an iconic steel structure using mass timber elements. Naturally, MGA chose to envision the Empire State building as a mass timber tower, replacing steel girders and beams with glulam structures joined by metal plates. With slight modifications to the existing tower’s structural design, MGA was able to pull off a mass timber replica that matched the Empire State Building’s height inch for inch. Réinventer Paris/Baobab Tower The firm’s Réinventer Paris project proposes a large-scale, 35-story mass timber tower complex that would span over Paris’s Peripherique highway belt. The innovative and speculative proposal attempts to explore a new model for high-density housing that encompasses a variety of functional uses—market-rate and social housing, a student-oriented hotel, and a bus depot—dispersed throughout a series of high- and midrise timber structures. The timber towers feature CLT columns that frame indoor-outdoor verandas, with lower buildings clad in wood louver assemblies.