Friday, March 31, 2017

Ten steps to reducing embodied carbon

By taking these steps upfront, architects can make a big impact during the building stage of a project

By Larry Strain, FAIA, March 29, 2017 

Ten steps to reducing embodied carbon
The early stages of construction for a net zero, low-carbon, LEED Platinum school project,
designed by Siegel & Strain Architects.

The need for sustainability in the design, construction, and operation of buildings is a reality. According to the Energy Information Administration, about 40 percent of the energy consumed in the United States in 2015 went directly or indirectly to operating buildings.

When you add embodied carbon—the energy and emissions from materials and construction—that number is almost 50 percent. As architects, we have the ability and responsibility to provide solutions that minimize the climate impact of the structures we design. And while practices to reduce operating impacts are widespread, less well understood are the carbon impacts during the building stage of a project.

My own “a-ha” moment on this front was when my firm calculated all the embodied carbon emitted from building the Portola Valley Town Center. It’s a very efficient project and has performed better than expected, but when we ran all the numbers we found that construction still emitted 1,000 tons of carbon—roughly the same as 10 years of operating emissions.

The good news is there are several steps architects can take to make significant upfront impacts in the design and construction process.

Reuse buildings instead of constructing new ones. Renovation and reuse projects typically save between 50 and 75 percent of the embodied carbon emissions compared to constructing a new building. This is especially true if the foundations and structure are preserved, since most embodied carbon resides there. With many projects, the first question should be, "Is there an existing building we can use instead?" This is an admittedly hard sell for architects—after all, many of us got into the business for the excitement and challenge of designing something new from the ground up. But channeling that energy and creativity toward making poor-performing buildings into something beautiful, sustainable and energy efficient has its own rewards, and yields substantial positive benefits.

Specify low-carbon concrete mixes. Even though emissions per ton are not relatively high, its weight and prevalence usually make concrete the biggest source of embodied carbon in virtually any project. The solution? Work with your structural engineers to design lower carbon concrete mixes by using fly ash, slag, calcined clays, or even lower-strength concrete where feasible. Though access to these materials varies across the country, with an increasing number of options there is almost always something that can reduce the carbon footprint of your concrete mix.

Limit carbon-intensive materials. For products with high carbon footprints like aluminum, plastics, and foam insulation, thoughtful use is essential. For instance, while aluminum may complement the aesthetics of your project, it is still important to use it judiciously because of its significant carbon footprint.

Choose lower carbon alternatives. Think about the possibilities. If you can utilize a wood structure instead of steel and concrete, or wood siding instead of vinyl, you can reduce the embodied carbon in a project. In most cases, it’s probably not possible to avoid carbon intensive products altogether—metals, plastics, aluminum—but you can review Environmental Product Declarations and look for lower carbon alternatives.

Choose carbon sequestering materials. Using agricultural products that sequester carbon can make a big impact on the embodied carbon in a project. Wood may first come to mind, but you can also consider options like straw or hemp insulation, which—unlike wood—are annually renewable.

Reuse materials. Whenever possible, look to salvage materials like brick, metals, broken concrete, or wood. Salvaged materials typically have a much lower embodied carbon footprint than newly manufactured materials, since the carbon to manufacture them has already been spent. With reclaimed wood in particular, you not only save the energy that would have been spent in cutting the tree down, transporting it to the mill, and processing it, but the tree you never cut down is still doing the work of sequestering carbon.

Use high-recycled content materials. This is especially important with metals. Virgin steel, for example, can have an embodied carbon footprint that is five times greater than high-recycled content steel.

Maximize structural efficiency. Because most of the embodied carbon is in the structure, look for ways to achieve maximum structural efficiency. Using optimum value engineering wood framing methods, efficient structural sections, and slabs are all effective methods to maximize efficiency and minimize material use.

Use fewer finish materials. One way to do this is to use structural materials as finish. Using polished concrete slabs as finished flooring saves the embodied carbon from carpet or vinyl flooring. Unfinished ceilings are another potential source of embodied carbon savings.

Minimize waste. Particularly in wood-framed residential projects, designing in modules can minimize waste. Think in common sizes for common materials like 4x8 plywood, 12-foot gypsum boards, 2-foot increments for wood framing, and pre-cut structural members.

Larry Strain, FAIA, is a principal at Siegel & Strain Architects.

Monday, March 27, 2017

Architects take a stand on the Border Wall


Border Wall Divides Professionals

When President Trump announced his plans to build a border wall, “it felt a little like divine intervention for me,” says Brian Johnson, the principal of Collaborative Design Architects, a small firm in Billings, Montana. Johnson had already been sketching ideas for a border wall that resembled a series of hydroelectric dams, with curved concrete surfaces to foil climbers and a roadway on top for border-patrol vehicles. After Trump’s announcement, Johnson began refining the idea in anticipation of an RFP. He says, “I knew I had developed something capable of being more than just a wall.”

But where Johnson saw opportunity, many other architects felt outrage. “A border wall is just the wrong thing to do,” says Larry Strain of Siegel & Strain Architects in Emeryville, California. “It doesn’t make us safer, it doesn’t protect our jobs, and it is divisive rather than inclusive.” In early March, he and the members of his firm signed a pledge not to participate in the project, although, he says, they’d be happy to design a seat or a gate with the word bienvenidos.

The pledge was written by an advocacy group called the Architecture Lobby, which asked architects to walk off the job on Friday, March 10, to protest the RFP. Among the firms that complied was makeArchitecture of Chicago. According to its director, William Huchting, the six members of the firm stepped outside to discuss their problems with the wall, including its cost and the possible effect on immigrant communities, such as Chicago’s Little Village. “Hardworking immigrants have transformed 26th Street into the most vibrant shopping district outside of Michigan Avenue,” said Huchting. “We fear that this and other thriving neighborhoods will suffer if the wall is built.”

(Read the article here)

Friday, March 10, 2017


#NotOurWall–Siegel & Strain Architects participated in a Day of Action called for by The Architecture Lobby to protest the Trump Administration's call to construct a border wall. This grassroots action coincided with the closure of the first round of Requests for Proposals (RFPs) for the Department of Homeland Security's Southern Border Wall.

For more information about The Architecture Lobby, click here.

Read more about The Architecture Lobby in Metropolis Magazine.

Friday, March 3, 2017

Embodied Carbon Benchmark Study

What is the typical magnitude and range of embodied carbon of buildings?

The Embodied Carbon Benchmark Study is the first stage of the LCA for Low Carbon Construction project funded by The Charles Pankow Foundation, Skanska USA and Oregon Department of Environmental Quality. Life Cycle Assessment (LCA) is the method used to quantify the carbon emissions that occur when extracting materials and making building products, otherwise known as “embodied carbon.” Although there is growing recognition of the need to track and reduce embodied carbon emissions, building industry professionals need better data and guidance on how implement low carbon methods in practice. 

This project compiled the largest known database of building embodied carbon and created an interactive database. This stage of the project established consensus on the order of magnitude of typical building embodied carbon, identified sources of uncertainty and outlined strategies to overcome this uncertainty. The report summarizes the key findings of this research and provides the foundation for stage two of this project, the development of an LCA Practice Guide due by the end of 2017.

You can download the Final Report and Database as well as interact with the data visualization.

Research Team
K. Simonen (PI), B. Rodriguez, S. Barrera, M. Huang, E. McDade & L. Strain

This research was funded by the Charles Pankow Foundation, Skanska USA and the Oregon Department of Environmental Quality. The success of this project would not have been possible without the donation of the original LCA database from Arup as well as additional databases provided by: The International Living Future Institute, Kieran Timberlake, the MIT Concrete Sustainability Hub, MIT DeQo/Thornton Tomasetti, Skidmore, Owings & Merrill (SOM) and the WRAP database in addition to individual LCA studies provided by firms and organizations.