According to a 2020 report published in Nature, up to 20 percent of the global carbon budget could be consumed by construction over the next 30 years. The Environmental Law Institute’s tenth GreenTech webinar on Green Construction: The Future of Building, moderated by Lawson Fite, co-chair of Marten Law’s natural resources practice, explored how potential and novel applications of existing technology—especially in wood products—can reduce commercial and residential buildings’ carbon footprint along the entire supply chain.
Panelist Marta Bouchard, sustainability lead for multinational software company Autodesk, described the need for a transformation in the architecture, engineering, and construction (AEC) fields. To address the opportunity for reducing industry emissions in the built environment, Autodesk creates software to automate how things are designed in the digital world and made in the physical world, including skyscrapers, bridges, smart cars, blockbuster films, and other products.
The AEC industry faces challenges associated with energy and carbon, climate adaptation and management, material use, and waste reduction. The construction industry’s approximately 11 percent of total global carbon emissions, including from the manufacture of construction materials such as steel, cement, and glass, compares with the 2 percent emissions by the entire aviation industry. The annual operation of buildings using electricity, oil, and gas makes up another 28 percent of annual global emissions.
As energy codes become more stringent, and building improvements cut energy consumption, the operational carbon footprint will shrink, but energy use is not the whole environmental footprint, Bouchard said. Traditionally, construction has employed a linear process in which buildings are designed, built, operated, and torn down at the end of their lives. But now lifecycle thinking, assessing the whole life of buildings from cradle to grave, must be applied. She emphasized “cradle-to-gate” embodied carbon, the upfront carbon generated by the materials extracted, processed, and manufactured up until a building is constructed. The “embodied carbon” is locked in place once a building is erected. Because applying sustainability as an afterthought is difficult, costly, and inefficient, it should be applied early in the planning and design process to drive sustainable outcomes.
Bouchard described several tools Autodesk has developed that bolster AEC sustainability and noted several major projects that have used the tools. The Building Information Modeling (BIM) is a holistic process of creating and managing information for a built asset. The tool integrates structured, multi-disciplinary data from all the AEC professions to give a three-dimensional digital representation of an asset across its lifecycle, from planning, to construction, to operation. Globally, 22 nations have adopted BIM policies and governments are enacting energy efficiency and green building mandates. The European Union is evaluating a whole life emissions policy, and the United States government is launching a buy clean task force across federal projects, along with other developments.
Panelist Dawn Garcia, marketing communications manager for Roseburg Forest Products, provided the granular perspective of one company that is using innovative technology, chemistry, and science to develop engineered wood that supports the AEC communities’ green building and sustainability initiatives. A privately held, vertically integrated company, Roseburg owns timberland, grows trees, and makes wood products with a focus on optimizing the full use of its materials. For example, when a log is cut into lumber, the branches and narrow top of the tree that are unusable for construction products are not wasted. Wood chips are used for paper, packaging, corrugated material, and as fuel in an energy plant. Sawdust, shavings, and wood debris are combined with chemistry to make durable composite products from 100 percent recycled wood. Engineered wood, Garcia explained, basically uses thin strips of veneer peeled from a log. The veneers are stacked up, glued together with resins, and pressed and heated to make long billets that can be cut into smaller products meeting different functional and structural needs, such as headers over windows, beams, columns, and studs. Among the other uses of materials in varied applications, beautiful hardwood veneer is added to cabinetry, wall paneling, and other products. The engineered wood process is an efficient way to use raw materials without needing to use the whole tree.
Garcia summarized three decades of trends in green building. In the 2000s, a focus on making buildings more energy efficient inspired innovation in lighting, insulation, HVAC, and other technologies. But buildings became airtight, raising concerns about indoor air pollution, so in the 2010s the focus shifted to transparency about the safety of building products and measuring air quality. Now in the 2020s, the focus is much more on the embodied carbon in buildings and how choices about materials affect a building overall.
Panelist Kyle Freres, vice president of operations, Freres Lumber Co., Inc., noted that in making its primary product of veneer, the rebranded family-owned Freres Engineered Wood achieves close to a 70-75 percent recovery factor from a log, compared with the typical 50 percent factor for lumber. The company peels veneer from logs, but also uses chips, sawdust, bark, even the carbon-rich biochar byproducts from its co-generation operations that can sequester carbon in soil for thousands of years. The thin veneer pieces that are reconstructed into larger pieces of wood are engineered to perform predictably in the built environment, a critical requirement for an architect or engineer aiming to design a safe building efficiently without too much or too little material. Because products are premanufactured, they generally cut waste and reduce labor on a job site, making a building simpler to construct, with fewer connections, and with improved fire performance.
Freres explained that engineered wood provides flexibility in building the panels both efficiently and for particular structural purposes. Another benefit of veneer is that the knots in the wood are not cut out of the product, whereas in a board the defect might be cut out and the board finger-jointed back together. Unlike heavy timber beams that need a larger tree to cut a 24-inch column, engineered wood can create enormous products using very small trees. Freres looks for second-generation logs typically cut down for thinning operations as wildfire control. Also, unlike timber, engineered wood typically has no defects such as a knot that could be a structural problem for timber beams. Engineered wood beams do not split, twist, or warp, and engineered products have a safety factor built into their certification, which is more stringent than for glued laminated timber.
“Technology makes all this possible,” Freres said, noting that 3D BIM design is “absolutely necessary” because predesigning is required for these engineered products.
Learn more about the GreenTech Webinar Series at https://www.greentechconference.org/webinar-series. For more on addressing climate impacts from our built environment, check out Bill Caplan’s Thwart Climate Change Now: Reducing Embodied Carbon Brick by Brick (ELI Press 2021).