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.
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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.
This is the fifth column of “Practice Values,” a bi-monthly series by architect and technologist Phil Bernstein. The column focuses on the evolving role of the architect at the intersection of design and construction, including subjects such as alternative delivery systems and value generation. Bernstein was formerly vice president at Autodesk and now teaches at the Yale School of Architecture. The topic this week in my practice class is “Scope of Services,” where we examine the architect’s relationship to the client’s work, to wit: What, exactly, does she have to do to deliver the project? The idea of “Basic Services” is central to explaining traditional practice, in that it’s the way we routinize our efforts through standard stages of effort (schematic design, design development, and so forth), structure decision-making, and, almost as important, create a basis for protecting our limited fees and invoicing the client. The idea of basic services or even “phases of design” has been under pressure for some time, mostly under the delaminating influence of technology. Long gone are the hand-drawn, single-line diagrams that once comprised the end product of schematics, just as transferring design intent to a builder may include BIM data or digital geometry in addition to traditional two-dimensional construction documents. The fluidity of digital data, and the purported insight that accompanies it, has blurred and expanded the system boundaries of services themselves. Nowhere is this more apparent than in the latest thinking about the use of mass timber as a fundamental building material for cities, work pioneered by my faculty colleague Alan Organschi of Gray Organschi Architecture. Alan argues persuasively that there is an opportunity to rethink the systems of carbon, energy, material production, design, and construction by the thoughtful and systematic use of engineered lumber—a renewable resource—in urban construction, where the forest is not just another source of raw material but also a place to store carbon. His thinking is not unlike Kiel Moe’s at Harvard, who posits that buildings aren’t independent objects that merely coexist with the systems that produce and sustain them, but rather are integral parts of those systems. Architects should ignore the resulting system boundaries created by constructs like, for example, the idea that our work be something called “Basic Services.” Both Organschi and Moe believe that architects must change the scale of their influence beyond the materialization of form by understanding, incorporating, and (dare I say it) controlling the flows of capital, energy, materials, and production. We need to replace our understanding of the supply chain with an overt ability to create and optimize it. This idea is immediately appealing, harkening back to the original assertions of modernism and its putative benefits for production and society, but equally daunting and intractable. This is precisely why Organschi’s claims about mass timber are so important: They represent a clear “through-line” from the means of making to the creation of form that is at the heart of the architect’s design proposition. Architects have always been part of a systems-design problem, and today’s digital tools that allow the representation, analysis, and optimization of systems fit perfectly into these new responsibilities. The digitization of design has blurred the traditional boundaries of our “systems of service,” but there are new opportunities emerging as design is informed by new technologies like systems engineering, big data analysis, and optimization, machine learning, and integrated network design. These tools will wend their way into innovative practices like Organschi’s, necessary to increase the architect’s understanding of and span of control over the supply chain. Organschi’s work thus challenges the entire idea of “Basic Services” as it currently drives practice—calling into question the roles of technology, research, professional certification, even the compensation to the architect for taking on such responsibilities. A “net zero” building means nothing if the systems that delivered it generates huge amounts of unaccounted carbon. We’ll need to reconsider and remediate all the systems boundaries of design—our internal protocols and processes and our relationship to the supply chain—to have true influence on the implications of our buildings. The efforts around mass timber described in this issue are some of the best thinking on this front so far.
AN Midwest Editor Matthew Messner spoke with Daniel Safarik, editor for the Council on Tall Buildings and Urban Habitat (CTBUH), about its “Tall Timber: A Global Audit.” The audit documented proposed, under-construction, and built tall buildings that use mass timber as their primary structural materials. The Architect’s Newspaper: What Prompted the CTBUH to conduct an audit of timber projects around the world? Daniel Safarik: We track all kinds of tall building construction routinely for the Skyscraper Center database and for our Global News feed on our website. The first well-publicized tall timber building was Stadthaus in London, which was completed in 2009. We noticed what seemed like a spike in announcements of timber tall buildings being proposed and constructed about four years ago , and everything that has happened since has reaffirmed this impression. When we saw the buy-in from the U.S. government represented by the U.S. Tall Wood Building Competition, in October 2014, that confirmed the impression that this really had momentum behind it, so we committed to tracking the two resultant projects through to completion. Unfortunately, the New York project was canceled due to market feasibility concerns, but the Portland project is now under construction. So the momentum began to build from that point, and we formed a Tall Timber working group in late 2014. The group started working on a design manual in mid-2015, and that effort has now gotten a turbo boost with the audit and the upcoming workshop at our 2017 conference, which is bringing together a lot of the key participants. Were there any interesting surprises once the information was gathered? The most striking thing was the diversity of construction methods that are being used to create these buildings, which are specific to local jurisdiction and the nature of the timber supply in each region. Of course, herein lies the difficulty of generalizing about what’s going on in tall timber worldwide, as well as coming to a consensus about classification and best practices—that is our challenge. What are some of the interesting discussions happening around mass timber? It’s encouraging to see the range of proposals, from both a stylistic and construction standpoint. The primary discussions revolve around fire safety and code, sustainability, and the feasibility of modifying fabrication techniques from mass production of stick-built single-family and platform-framed low-rise buildings to something that is workable for high-rise. What do you think the next steps are, or barriers to overcome, for mass timber to become a common building method? The foremost obstacle is local fire codes. Most fire codes prohibit wood structures from rising above five or six stories. Many codes stipulate that a building of this height must also have a concrete base, particularly if there are commercial uses on the ground floor, such as restaurants, or if there is vehicle parking, to give one to three hours of fire protection that would allow safe exiting before structural collapse. This is predicated on the assumption that wood high-rises would use platform construction, with dimensional lumber such as two by fours, beams, and joists, similar to those currently permitted. The key to mass timber’s viability as a structural material for tall buildings lies in its name. Massive wood walls and structural beams and columns comprised of engineered panels have demonstrated fire performance equal to concrete and, in some cases, superior to steel. Wood unquestionably burns, so there would be smoke issues, as with any fire, which would require proper sprinklering, pressurization, and other tactics used in tall buildings today. But mass timber has to burn through many layers before it is structurally compromised—basically it “chars” long before it collapses. As more jurisdictions come to appreciate the aesthetic, economic, and environmental advantages of tall timber, fire codes are expected to change. The second-biggest obstacle is a lack of standardization of construction materials, methods, and definitions. There are many forms of mass timber, and a wide degree of variance in approach when it comes to supporting tall timber structures. Thus, there is a range of techniques, from assemblages of highly similar panels for both floors and walls, to complex column/beam/outrigger combinations, such as are found in high-rises of steel and concrete. There are numerous proprietary systems, and the connections between elements also vary widely—often it is the location and orientation of the steel connectors between wood elements that can make all the difference in how long a structure can withstand fire or seismic action, and thus determine its feasibility under local code. Are there any proposals, speculative or real, that you are particularly excited about? I like the one we published in the CTBUH Journal for Chicago: the River Beech Tower. It would be great to see that go up in our home city.
As the race heats up to demonstrate that timber is a viable alternative to concrete for mid and high-rise buildings, Portland, Oregon, has been leading the way in realizing mass timber projects. The latest to claim the country’s tallest timber building crown is Carbon12, an 85-foot tall mixed-use building in Portland, designed by PATH Architecture. Built with a mix of glulam beams and cross-laminated timber (CLT) surrounding a central steel core, the eight-story building was designed to have a minimal environmental impact and promote Oregon’s local timber industry. As downtown Portland addresses a growing demand for housing, timber projects constructed with prefabricated CLT panels cut off-site, like Carbon12, hold a speed advantage over traditional steel and concrete techniques. Carbon12 features a mix of 14 residential units, each with their own recessed balcony, as well as retail on the ground floor and a mechanized underground parking system. While the exterior is clad in vertically striated metal paneling that recalls timber grain, PATH chose to accentuate the natural materials of the interior spaces by leaving the wood columns, beams, and undersides of the CLT slabs exposed for a warmer feel. PATH’s focus on sustainability as a requirement in part drove their decision to use timber for Carbon12. Because locally grown timber can sequester more carbon dioxide than is used to grow and transport the wood, it often has a smaller carbon footprint in production than steel or concrete. Carbon12 will also feature solar panels on the roof. Although Carbon12 is currently the tallest timber building in the U.S., it won’t be for long. The 148-foot tall, 12-story Framework building, also in Portland, is shooting to take the title once it finishes in winter of 2018. Designed by LEVER Architecture and the Framework Project, Framework will feature a wood core as opposed to steel. Still, as timber buildings continue to push higher and higher, they may be paving the way for the eventual acceptance of timber as a mainstream urban construction material. Carbon12 is now fully complete and units are available on the market.
2017 Best of Design Award for New Materials: Indiana Hardwood Cross-Laminated Timber Project Designer: IKD Location: Columbus, Indiana The Indiana hardwood cross-laminated timber (HCLT) project is the first commercial pressing of HCLT and the first use of HCLT in a built project in the United States. IKD aspires to create a new timber product by upcycling low-value hardwood sawn logs that are extracted from Indiana forests. Indiana’s largest cash crop is hardwood, but over 55 percent of each log processed is of low value. The firm set out to demonstrate how low-value hardwood can be used to create high-value HCLT, which can then be used as the primary structure for buildings. This process has the potential to initiate a cascade of effects: positive job growth in rural forestry and manufacturing, hardwood lumber market expansion, forest land value increase, and improved forest management practices. HCLT offers numerous benefits over softwood, including superior mechanical properties, material volume savings, and increased fire resistance. “The use of hardwood in mass timber is appealing on many levels. Its added strength and durability over softwoods makes it ideal for exterior applications.” —Nathaniel Stanton, principal, Craft Engineer Studio (juror) CLT Fabricator: Smartlam Timber Engineers: Bensonwood General Contractor: Taylor Brothers Construction Hardwood Material Supplier: Koetter Woodworking Grant Funding: United State Forest Service Wood Innovation Grant
With mass timber projects on the rise around the United State, Skidmore, Owings & Merrill (SOM) and Oregon State University (OSU) have partnered to produce two new reports on how timber buildings can overcome their technical limitations by integrating steel and concrete. The new composite systems being proposed would allow timber construction to rise higher than before, with longer floor spans. The OSU Testing Report, released earlier this month, looked into the possibility of combining cross-laminated timber (CLT) floor systems with a concrete topper, to improve the strength of the flooring as well as lengthen its span. To accurately represent real-world conditions, the SOM team first drew up plans for a “typical” 11-story residential building and indicated where the wood columns would normally be. With the floor span determined, the CLT flooring was stress tested for load, bending, cracking and shearing, before and after the application of a concrete slab. A 2.25-inch thick concrete layer was applied over a 6.75-inch thick CLT floor for the experiment. After testing smaller, individual sections, an eight-foot-by-36-foot full-sized mockup was created and subjected to load testing, only failing after engineers applied eight times the normal service load, or around 82,000 pounds of pressure. One complicating factor is that CLT can be charred for a higher fire rating at the expense of its strength, and any real-world application of CLT would need to be thicker than in testing conditions. Still, the results are a promising first step to increasing floor spans in timber buildings as well as improving their acoustic properties. The second report was produced in conjunction with the American Institute of Steel Construction (AISC) and examined how steel framing can best be integrated with timber floor systems. Because steel framing can span much greater distances than timber with smaller columns, and because CLT is lighter than concrete, a building that uses both should get the best of both worlds. In SOM’s modeling, this combination model was equally as strong as a steel and concrete building while offering window bays of the same size as a typical residential building. Ideally, high-rise timber construction of the future would combine both of these techniques, as the concrete slab topper adds extra seismic protection. With timber construction offering the potential for more sustainable, durable and quickly assembled towers, hybrid research could be a stepping stone towards bringing mass timber construction into the mainstream. All of SOM’s timber research reports can be found here.