Posts tagged with "Cross-Laminated Timber (CLT)":
Climate-change denial appears to be on the verge of becoming official U.S. policy. But all hope for reducing our carbon footprint is not lost. Case in point is the pending Timber Innovation Act, one of the rare eco-friendly pieces of legislation that enjoys bipartisan support. The bill (H.R. 1380, S. 538) seeks to establish a market for so-called mass timber buildings more than 85 feet tall that are built from panelized wood construction products such as cross-laminated timber (CLT) and glued-laminated timber (glulam).
“Building with wood benefits both rural economies and the environment,” U.S. Senator Debbie Stabenow (D-Michigan) said when she announced the legislation in early March. “This bill will help expand markets for wood products coming out of forests in Michigan and all across the country. At the same time, using wood for construction reduces pollution and incentivizes private landowners to keep their land forested, rather than selling it to developers.”
Architects who study the new wood construction materials say mass timber has economic, ecological, seismic, and aesthetic advantages over steel and concrete. “Photosynthesis, the process of growing a tree, absorbs C02,” explained New Haven architect Alan Organschi, adding, “Until it burns or decomposes, that carbon will stay in the wood like a bank investment.”
The concrete and steel industries are adamantly opposed to the Timber Innovation Act. More than 160 stakeholders from the construction, labor, and building materials sectors jointly signed a letter to the U.S. Senate opposing a version of the bill introduced last year. The letter questioned the fire and structural safety of mass timber and stated the bill would create an “imbalance in the marketplace by allowing the federal government to choose winners and losers.”
However, the bill’s supporters say the new wood technology promises to significantly reduce carbon loads in the building industry, which is currently responsible for close to half of the U.S.’s greenhouse gas emissions. A typical mid-rise concrete and steel building, because it relies on pollution-generating resource-extraction industries, is responsible for emitting 3,210 tons of CO2 in its construction and lifetime, according to Timber City, an initiative undertaken by Organschi’s firm, Gray Organschi Architecture, that is supported by the Hines Research Fund for Advanced Sustainability at Yale University. In contrast, because trees are a renewable resource that sequesters CO2, a typical mass timber mid-rise building built from wood harvested from sustainably managed forest is responsible for capturing 4,720 tons of CO2.
Innovations in mass timber technology also resolve fireproofing and seismic issues that, until recently, were a major disincentive to using wood in large urban buildings, according to Yugon Kim, founding partner of the architecture firm IKD, who curated the exhibit Timber City at the National Building Museum in Washington last fall. “U.S. cities in the 1800s used to be made of wood, but then because of urban fires that started to change,” he said. “Now, because of products like CLT, we will be able to use wood in the centers of our cities the way we did in the past.”
Tall wood building construction is most advanced in Europe, especially in Austria, which boasts the world’s largest mass timber industry. An example of a commercially viable mass timber development that garnered worldwide attention is the nine-story Murray Grove designed by Waugh Thistleton Architects, which was built in London in 2009. It consists of wood load-bearing walls, wood elevator cores, and wood floor slabs. In addition to paying off for the environment, Murray Grove took only 49 weeks to build, whereas an equivalent-size concrete structure would typically have taken 72 weeks to build.
The mass timber industry is still in its infancy in the U.S. There are only several wood companies that make mass timber products, and local building codes generally disallow tall wood structures. The Timber Innovation Act seeks to change that situation by funding competitive research on mass timber technology at institutions of higher learning and by making funds available for a tall wood building competition and a wood innovation program for retrofitting sawmills in areas where there is high unemployment.
The pending legislation expands upon a federal program that established an earlier U.S. Tall Wood Building Prize Competition, which in 2015 awarded $3 million to support the construction of two such structures. One was Framework, a 12-story mixed-use building in Portland, Oregon, designed by LEVER Architecture, which is due to break ground this summer. The other was 475 West 18th Street, designed by SHoP Architects, an upscale residential building project near the High Line that was shelved in early March, reportedly in response to a market downturn for high-end properties.
Getting government sponsored research funding was critical to defraying added expenses associated with the extensive testing and research necessary to secure local building department approvals for building wood structures more than six stories, according to Thomas Robinson, founding principal of LEVER Architecture. “Whenever you are doing something for the first time it is more complicated,” he said, noting that a critical aspect of his project was demonstrating that exposed CLT and glulam can achieve a two-hour fire-resistant rating.
Given the increasing environmental concerns over the widespread use of steel and concrete, mass timber promises to be a more palatable alternative. “What the Timber Innovation Act does is make this an even playing field,” Organschi said. “We have these vast forest reserves which are not being utilized.… By using mass configurations of timber, we will get more carbon sequestration.”
From my own teaching experience there’s nothing more potent than being able to talk with students about the space around you—in this case, the building’s collaborative configuration, innovative structure, considered material and detailing choices, environmentally-driven site, and synergistic landscape concepts that define the project.The building is organized around an interior atrium lit during the day by several skylights. This daylighting strategy reduces energy consumption and provides the school with a bright central space for exhibitions, design critiques, lectures, informal gatherings, and other events. The studios and classrooms are arranged around the atrium, visually connected to the commons through window apertures that allow visitors to glimpse the work being done by the students and faculty. The design of the building’s commons also emphasizes the unification of the university’s departments of Architecture, Landscape Architecture and Regional Planning, and the Building and Construction Technology program into one singular facility. In addition to its extensive use of wood products, the architects chose to clad the building with copper-finished aluminum panels that protect the highly-efficient envelope. Though the building fills much of the site, the landscape design by Stephen Stimpson Associates strategically uses native plants and local paving materials to connect the building to the larger campus. In the end, the building cost $52 million to construct, a price tag that was partially funded by Massachusetts State Legislature, and adds 87,500-square-feet of additional interior space to the university. Suffolk was the construction manager.
The Architectural League’s Emerging Voices award and lecture series spotlight individuals and firms with distinct design “voices” that have the potential to influence the discipline of architecture, landscape architecture, and urban design. The jury, composed of Sunil Bald, Mario Gooden, Lisa Gray, Paul Lewis, Jing Liu, Thomas Phifer, Bradley Samuels, Billie Tsien, and Ian Volner, selected architects and designers who have significant bodies of realized work that creatively address larger issues in the built environment.
The Architect’s Newspaper featured the Emerging Voices firms in our February issue; stay tuned as we upload those articles to our website over the coming weeks. The firm featured below (Portland, Oregon–based LEVER Architecture) will deliver its lecture on March 16, 2017, at The Architecture League in New York City. Click here to learn more!
Architect Thomas Robinson kick-started his career with Joseph Esherick, the architect best known for designing the Hedgerow Houses at Sea Ranch, California, followed by stints leading institutional and cultural projects at Herzog & de Meuron in Switzerland and Allied Works in Oregon. In 2009, Robinson, a graduate of UC Berkeley and later Harvard (studying under Peter Zumthor), decided to branch out on his own, launching LEVER Architecture from his Portland basement.
Over the past eight years, his firm has grown to 18 employees. A winner of the USDA’s U.S. Tall Wood Building Prize, LEVER Architecture has found a niche working with cross-laminated timber (CLT). “Timber is often hidden away,” Robinson said. “We want [timber] to be part of a greater architectural experience.” While mass timber construction isn’t new—according to Robinson it has been around since the 1930s—there is a rediscovering and understanding of the technology coupled with modern advances in fire safety, seismic engineering, and acoustics that has made it more feasible.
LEVER Architecture is currently working on a 90,000-square-foot, 12-story CLT high-rise in Portland. The project, Framework, incorporates a wood-core structure. When completed in 2018, it is expected to be the first mass-timber high-rise in the United States. The design relies on a post-tension CLT rocking wall, which, as Robinson explained, is a resilient low-damage design that takes advantage of the lightness and strength of wood. “Wood moves and can re-center itself,” he said.
Other recent LEVER projects also feature mass timber: There is Albina Yard, the first office building in the U.S. built with domestically manufactured CLT (LEVER Architecture recently moved its offices to this four-story, 16,000-square-foot building), and L’Angolo Estate, a winery tasting room in Newberg, Oregon.
At the core, Robinson explained that LEVER’s design projects are about the transformative power of materials. “It’s almost akin to product design at the level of a building.”
With funding from the National Science Foundation and a $1.8 million grant through the U.S. Tall WoodBuilding Prize, LEVER is implementing a performance-based design process throughout its projects. The grants help pay for additional research costs to demonstrate that CLT high-rise buildings are equivalent to traditional steel construction.
LEVER advocates mass timber as a more sustainable way of building while encouraging economic growth in the Pacific Northwest. “We look to the farm-to-table model, where people are connected more directly to the producer,” Robinson said. Translated from the culinary scene to the architecture world, the “forest-to-frame” approach is about building stronger relationships between architects, contractors, and the people growing the timber.
“We focus on simple materials and how to put them together to form transformative experiences,” Robinson said. “We’re interested in an economy of means. It’s rare being both at the cutting edge and having a seat at the table.”