Monday, December 18, 2017

Part III: Time Value of Carbon

when you save matters
what you build matters

what you don't build matters more
by Larry Strain, FAIA

(continued from Part II)
Given the amount of embodied emissions from new construction and the amount of operating emissions from existing buildings, a combined strategy of reusing and upgrading existing buildings, building fewer new buildings and reducing embodied carbon emissions from construction is the most effective way to reduce emissions quickly. When the renovations include deep energy upgrades—even making existing buildings net zero energy and emissions, we address two sources of GHG missions at the same time. We reduce embodied emissions compared to new construction, and we reduce operating emissions from existing buildings by making them more efficient.

Reducing operating emissions is not technically difficult; we already know how to do it.

  • Improve system efficiency—lighting, HVAC systems, equipment, controls, etc.
  • Improve the building envelope—insulation, windows, shading, air sealing, daylighting.
  • Power them with renewable energy.

We recently co-authored a study with the Integral Group of a two-story office building renovation and upgrade for DPR Construction. This remodeled office building is currently generating more energy that it consumes, making it a net positive building.

The interior remodel upgraded equipment and lighting, added skylights and photovoltaics (PVs), with only minimal upgrades to the envelope (roof insulation). The remodel generated about 1/3 of the embodied emissions that building a new building would have, and because it is producing more power than it uses it is paying off that embodied carbon debt.

The building wasn’t even a particularly ideal candidate for a net-zero retrofit. It is partly shaded by taller buildings, and the single glazed aluminum storefront windows couldn’t be replaced because they were historic. The most compelling part of this story is that even without ideal conditions, it still made sense to retrofit; the project came in on budget and on time.

The priorities for deep energy upgrades for existing buildings have changed over the last decade. In the past, you started by upgrading the building envelope—adding insulation and high performance windows, and maybe upgrading the lighting. With the use of blower-door tests and highly efficient and relatively inexpensive heat pump technology, air sealing and equipment upgrades are now also among the first upgrades we might undertake.

Efficiency strategies may vary depending on whether the building is residential or commercial. Commercial buildings generally have higher internal loads, which means that for commercial buildings, lighting and equipment upgrades may have a larger impact on reducing energy and emissions than envelope upgrades. Residential buildings tend to be dominated by external heating and cooling loads, and envelope upgrades may have a bigger impact, although appliances and equipment upgrades are also important.

Another thing that has changed is our understanding of the urgency of addressing climate change. As previously stated, we need to drastically reduce total carbon emissions—operating and embodied—over the next 10-30 years, and to do that we need to evaluate energy efficiency strategies based on the initial embodied carbon investment to achieve the strategy against the future operating savings generated from the efficiency upgrade. How much carbon did we spend to reduce operating emissions, and how long will it take the savings from increased efficiency and clean energy production to off-set that initial investment? When you do this analysis it may change your approach to efficiency upgrades. Blowing in insulation, re-commissioning or even replacing inefficient HVAC and lighting systems are likely to have a good return on carbon invested; re-skinning a building with a high-performance aluminum / glass curtain wall or wrapping the building in foam insulation may not be a good investment from a carbon standpoint. It may even make sense to add PVs before achieving that last few % of efficiency. The point is, we need carbon reduction strategies that have a positive payback within a 30-year time frame and ideally within 10 years.

Because reusing the foundation, structure and envelope saves a lot of embodied carbon compared to building new, some buildings are more important to reuse than others. Large, heavy commercial buildings offer a greater potential for reducing embodied emissions, because replacing this type of building will have a higher carbon footprint than replacing small residential structures. The good news is we have a lot of these buildings. There are almost six million commercial buildings in the U.S. and the majority of them are one- to three-story, flat-roofed buildings.


What are the best candidates for energy upgrades? We start with the buildings that use a lot of energy compared to similar buildings with similar uses. Poor performing buildings have a higher potential to save energy and reduce carbon emissions than more efficient buildings. These buildings usually have:
  • Poor thermal envelopes, little or no insulation, single glazed windows, unshaded windows, leaky, drafty buildings.
  • Old, inefficient HVAC and lighting systems and controls, and equipment and appliances.


Bringing existing buildings up to ASHRAE 90.1 2013— efficient but not necessarily to super-efficient—passive-house standards, would allow most of them to be converted to net zero energy. We have an abundance of one- to two-story strip malls, warehouses, schools and office buildings with large expanses of flat roofs, not to mention millions of single family homes. These are all prime candidates for efficiency and net zero upgrades.  The best candidates for zero net energy upgrades are: 
  • Buildings with unshaded flat roofs or south (in the northern hemisphere) and west facing sloped roofs.
  • One- to three-story story buildings: 76% of commercial square footage and 96% of residential square footage are one- to three-stories.
  • The majority of existing buildings in most climate zones—offices, retail, schools, warehouses, apartments and single family homes—could be converted to net zero energy.
  • Buildings with adjacent unshaded land. Parking lots with PV canopies produce power and have the added benefit of shading the cars and pavement and reducing the heat island effect around the building.
  • There are a number of building types and configurations that can’t be made NZE using only the roof and walls of the building—buildings over four stories, high-energy use buildings such as restaurants, hospitals and data centers. These will require off-site district or community based solutions.
  • To also achieve net-zero emissions, we also need to eliminate the use of on-site fossil fuel combustion and convert them to all electric.


  • Identifying the best buildings to retrofit and upgrade to zero.
  • There are limited incentives and regulations that require existing buildings be upgraded.
  • It can be expensive to make an existing building more efficient and power it with renewable, clean energy.
  • Addressing potential moisture and condensation issues when we upgrade existing buildings.
  • All upgrades require an investment of eCO2. We need simple ways to calculate the carbon invested and how long will it take the savings from increased efficiency to offset that investment.


  • We still will need new buildings. Buildings wear out, priorities change, populations shift and grow, but we need to make reusing and upgrading existing building a much higher priority.
  • Every building won’t get to net zero, but we can make all existing building more efficient. We need to identify and target the best candidates and focus on them first, high energy use buildings and low-rise commercial and residential buildings. We could be retrofitting a lot more buildings to very low energy or ZNE.
  • Reusing and upgrading existing buildings makes more sense in places that are mostly developed, such as the US and the EU. For countries that are still building a lot of new buildings like China and India, the focus will need to be more on reducing the embodied carbon in new construction (as well as making them ZNE).
  • Although this paper does not address transportation directly, locating buildings to minimize transportation impacts associated with building use is another a critical strategy for reducing emissions associated with buildings.  


Architecture 2030, 2030 Challenge for Products.

Carnegie Mellon, EIO LCA.

Carbon Leadership Forum, “Embodied Carbon Benchmark Study”

Cole, R. Kernan, P. “Life Cycle Energy Use in Office Buildings” Building and Environment Vol. 31, No.4, 1996.

Department of Energy, United States Energy and Information Administration, “Commercial Buildings Energy Consumption Survey” 2012.

Department of Energy, United States Energy and Information Administration, “Residential Energy Consumption Survey,” 2009.

Eley, C. “Design Professionals Guide to Zero Net Energy Buildings.”

Environmental Protection Agency, “U.S. Greenhouse Gas Inventory.”

Fernandez, N.P. “ The Influence of Construction materials on life-cycle energy use and carbon dioxide emissions of medium size commercial buildings” Thesis, School of Architecture, Victoria University of Wellington, NZ, 2008.

McGraw Hill Construction/Dodge, “U.S. Construction Outlook,” 2015.

Stein, R.G, “Architecture and Energy,” 1977.

Stein, R.G; Hannon, B.M.; Segal, B.Z.; Serber, D. “Energy Use for Building Construction,” 1977.

United States Census, “Characteristics of New Housing.”

United States Climate Action Report 2014 to the Intergovernmental Panel on Climate Change. No longer available on the State Department’s website, but still available as a PDF from:

For the complete report, please click here. 

Siegel & Strain Architects is thrilled to rebuild Berkeley Tuolumne Camp!

Berkeley Tuolumne Camp is a City of Berkeley family camp, located on a 30-acre site along the south fork of the Tuolumne River in the Stanislaus National Forest, just west of Yosemite National Park. The camp was destroyed by the 2013 Rim Fire.

The City of Berkeley hired a multi-disciplinary team lead by Siegel & Strain Architects to help rebuild camp facilities, including a new dining hall, recreation hall, camper and staff cabins, maintenance structures, pedestrian bridges, parking and loading areas, and infrastructure. The new camp buildings and landscape will evoke the rustic spirit of the old camp while using contemporary methods and meeting today’s codes. The S&S Design Team is honored to have been chosen to help reconstruct this beloved community camp.

Monday, December 11, 2017

Siegel & Strain Packs up and Moves in

On Friday, Oct. 27, after a long two days of packing, we said goodbye to our too small office at 1295 59th Street. Monday we started work in our new space, large enough to hold our expanding firm, two blocks north and right along Hollis-Doyle Park, at 6201 Doyle Street. Larry and Lauren had spent the weeks before designing our new space. They chose to replace the old carpet, beneath what would become our open bullpen of desks, with new light and dark grey carpet tiles and polished the exposed concrete that runs the length of the building to a reflective glow. A new fresh coat of crisp white paint went up on most walls, except for the accents walls in deep green. Lastly, the custom plywood desks went in, with us filing in eagerly to fill our chairs and get to work.

Check out some of our before and after photos below.

Wednesday, November 8, 2017

National Environmental Science Center


Another season of construction is speeding along at NatureBridge's new outdoor education campus, the National Environmental Science Center, located along Wawona Road in Yosemite National Park. The first five buildings are nearing completion and will allow NatureBridge to move its residential education program from aging facilities at Crane Flat to this cozy, resource-efficient and fully-accessible home base. With the first five buildings, the intent of the campus is now visible: sensitively sited and kid-scaled, each building is set along gentle, curving pathways, providing privacy and unique views. Cabins with front stoops and back decks will provide places to hang out and stargaze. The dining hall will provide an inspirational setting for meals and evening programs, while NatureBridge’s dedicated chefs provide healthy meals made from scratch in the new kitchen. Accessible paths will provide outdoor experiences for all, and jumping off points for hiking and snowshoeing. We expect programs to start in the Fall of 2018. At full build-out, NatureBridge will have capacity for 224 students and chaperones.

National Environmental Science Center cabins taking shape.

Thursday, September 7, 2017

LEAP Sandcastle Classic is coming to a beach near you on Saturday, November 11, 2017!

LEAP ARTS IN EDUCATION is a non-profit organization that brings arts education to Bay Area schools. Their residency programs place professional teaching artists in to elementary schools and middle schools to enhance classroom curriculum through creative projects.

The annual LEAP Sandcastle Classic contest is its largest fundraiser. Now in its 35th year, the competition brings together teams of students, architects, contractors and engineers. Each team designs a sand sculpture that is brought to life at this daylong event.

WHERE: Ocean Beach, San Francisco
WHEN: Saturday, October 14, 2017  NEW DATE! November 11, 2017

WHAT: Building a monumental sandcastle, of course!
The theme this year is CASTLES, CASTLES, CASTLES!

The students of Berkley Maynard Academy in Emeryville, California are shovel ready!


Siegel & Strain Architects pleased to be teamed with Clark Construction, McMillen Jacobs Associates, Holmes Structures, and Berkley Maynard Academy in Emeryville, California.

Click this link to donate to our team and to find out more. 

Thursday, August 24, 2017

Part II: Time Value of Carbon

when you save matters
what you build matters

what you don't build matters more
by Larry Strain, FAIA

(continued from Part I)
The U.S. is currently building about 6 billion sq. ft./year and demolishing about 1 billion sq. ft. —adding about 2% and replacing about 0.3% of our building stock. We build a lot more residential than commercial.

How much GHG emissions does this much construction release? There is currently no agency or organization that tracks embodied emissions nationally, but there are a couple of ways to estimate the embodied emissions from materials and construction. 

The big picture, top down approach uses an Economic Input/Output Life Cycle Assessment (EIO LCA). EIO LCA’s for construction assign emission factors per U.S. dollar of construction activity for different construction sectors of the economy—residential, commercial, manufacturing, and other categories of buildings. Carnegie Mellon has on-line EIO LCA models, that give emission factors for different sectors of the construction industry and McGraw Hill Construction/Dodge publishes annual construction data—square feet of construction and values of construction activity by building sector. Architecture 2030 puts annual U.S. eCO2 emissions from materials and construction at 5.9% of total U.S. emissions (based on updated EIO LCA numbers from Architecture and Energy, Richard Stein). 

Total U.S. emissions in 2013 were 6.3 billion tons
5.9% of 6.3 billion = 370 million metric tons or about 700 kg /m2 

Figure 3. Energy Use by End User Sector (Materials and Construction separated).
Note: although energy consumption and GHG emissions are roughly equivalent.

The bottom up approach calculates environmental inputs and outputs (including GHG emissions) from all the materials and construction activities that go into making a building by conducting a whole building life cycle assessment (LCA). You would need do this for all the different building types and then multiply that by the total number of buildings we build each year. Whole building LCA’s are becoming more common, but the number of buildings with whole building LCA’s is still very small. Whole building LCA’s use tools such as the Athena Impact Estimator that calculate environmental inputs and outputs from area take offs, or Tally—that gathers LCA data from Building Information Modeling (BIM), using Revit software.

The Carbon Leadership Forum (CLF) has taken the first step in collecting this data. They recently completed the Embodied Carbon Benchmark Project, gathering LCA data from over 1,000 building’s, and used the results to establish initial eCO2 ranges for different types of buildings. The eCO2 numbers from this study are lower than the numbers generated by EIO/LCA’s: 100 – 400kg/m2 (20–80lbs / ft2) for residential buildings and 290 - 500 kg/m2 (60–100lbs / ft2) for commercial buildings. This discrepancy may be explained by the fact that the whole building LCA’s do not capture all the embodied emissions associated with constructing a building. Building systems and equipment, some of the transport emissions, site work and infrastructure, construction equipment, and some interior materials—are typically not accounted for in many LCA’s. EIO/LCA’s on the other hand are based on whole sectors of the economy and may capture emissions beyond the boundaries of the building. 

For estimating annual embodied emissions at a national scale, EIO LCA’s give a big picture overview of emissions by sector, but they don’t tell us much about emissions associated with an individual building. For understanding emissions at the building level, whole building LCA’s provide a wealth of detailed emissions data for different materials and building types. This is especially useful if we want to target reductions by material or building type. As whole building LCA’s become more common, more of the data gaps will be filled in and the numbers will likely increase and get closer to the EIO/LCA numbers. 

REDUCING EMBODIED CARBON If we want to reduce embodied carbon it’s useful to know where it is. The chart on the right shows a breakdown for embodied carbon for a typical office building in North America. As the chart shows, most of the carbon emissions from construction come from the materials we build with. Construction equipment, transporting workers and materials to the job site and site work also contribute emissions—for remote sites transport can be significant and for large sites, site work emissions can be a larger percentage—but typically the majority is from materials. 

Figure 4. Where's the Carbon?
Source: Embodies Carbon Benchmark Project, and review
of multiple embodied energy and carbon studies.

It’s also useful to know the carbon footprint for different types of buildings and to understand how the materials and their carbon emissions are distributed (Figure 5). On a square foot basis, Larger heavier new buildings have a higher carbon footprint than smaller, lighter new buildings. Larger buildings weigh more per square foot because of what they are made of: beyond a certain size, buildings usually have steel or concrete structural systems, and steel and concrete have a larger carbon footprints than wood (although wood is now a viable alternative for large buildings). Small light buildings, at least in North America, have traditionally been framed in wood. It is worth noting that renovating even large, heavy buildings typically has a lower carbon footprint than building new small light buildings because you generally are not replacing the structural system which is where most of the embodied emissions are.  

Figure 5. Carbon Emissions by Building Type and Building Element
Source: Embodied Carbon Benchmark Project, Carbon Leadership Forum,
and review of multiple embodied energy and carbon studies.

Reducing embodied emissions by 20-30%, is feasible right now using readily available materials and current technologies. Reducing material quantities, particularly high volume, heavy materials such as concrete and steel, and high emission materials such as metals and plastics, is particularly effective. Ways to achieve this include designing more efficient structural systems, minimizing waste, more efficient construction processes, and minimizing energy and emission intensive materials such as aluminum and glass curtain walls. 

Using local, low embodied emission materials can reduce embodied carbon emissions even further. These materials are generally closer to their natural state—stone, clay, wood, straw—although when they aren’t close to the building site, transportation emissions can be a significant impact, which can reduce the efficacy of using these materials.

There are also materials that sequester atmospheric carbon—plant based materials, including wood and agricultural bi-products, lock up GHG’s that would otherwise be released when the material biodegrades or is burned, and there are emerging technologies for creating cementitious binders and aggregates from CO2e captured from power plants, steel plants and other industrial smokestacks. Materials that sequester carbon theoretically can be used to create carbon neutral or even carbon negative buildings. 

But there is another way to reduce embodied emissions and that is to reuse existing buildings and materials rather than build new buildings. Building renovations generate significantly lower emissions than new construction, typically 50–75% less than new buildings generate.  

Renovation projects have lower eCO2 than new construction because they generally reuse the structure and building envelope, which account for the majority of the eCO2 in a building. But even renovation projects generate embodied emissions, and we can reduce those if we pay attention. Renovation projects often remove and replace materials such as lay-in acoustic ceilings or worn out carpet. Instead of replacing them, we may be able to use the underlying structure as the new interior finish, reducing emissions, saving money, and transforming the space in the process. We can reuse the “waste” materials that are generated by renovation projects. New construction typically generates 3–5 lbs. of waste per square foot, but renovation projects can generate 20-30 times that much. When we reuse those “waste” materials instead of discarding them, we save carbon. We can use lower carbon materials to renovate building—insulating a metal warehouse with strawbales, using salvaged materials instead of new materials or even replacing synthetic carpet with natural fiber carpets.

We can also plan for future renovations, using building components that are easy to remove, clean, and refurbish. If people can change and renovate the buildings they already have more easily, they may be less likely to replace them.  

Compared to building a new building renovating an existing building clearly saves embodied carbon emissions. But to get the most out of reusing existing buildings we also need to lower their operating emissions. Operating emissions from existing buildings are a much larger source of emissions than the embodied and operating emissions from new buildings and the reason is scale: 

Figure 6. Annual Carbon EmissionsNew Construction: 6 billion square feet
Existing Buildings: 310 billion square feet

In the U.S., we are currently building about 6 billion square feet / year but we already occupy and operate about 310 billion sq. ft. Operating six billion square feet of new, efficient buildings generates about 40 million tons of GHG’s, less than 1% of total U.S. emissions. Building 6 billion square feet will generate about 350 million tons, just over 5% of our annual emissions, a significant
number. But it doesn’t begin to compare with the 2.3 billion tons of operating emissions from our existing buildings—more than a third of U.S. annual emissions. 

The majority of the buildings in use today will still be in use in 2030, so it is clear we need to reduce emissions from existing buildings.  
(to be continued)

Tuesday, May 30, 2017

Part I: Time Value of Carbon

when you save matters

what you build matters

what you don't build matters more

 by Larry Strain, FAIA


Climate change is time critical. If we continue with business as usual, global temperatures are predicted to rise 2°C above preindustrial times by 2030; this temperature change is widely accepted by the world scientific community as the point at which climate change becomes irreversible and catastrophic, often referred to as the global tipping point. We are about half way there, the climate has warmed by about 1° C. In 2013, the International Panel on Climate Change (IPCC) ran a number of emissions scenarios and only one kept us below 2°C: That scenario had emissions peaking by 2020 and fossil fuels phased out by 2055. When we evaluate emission reduction strategies, there are two things to keep in mind: the amount of reduction, and when it happens. Because emissions are cumulative and because we have a limited amount of time to reduce them, carbon reductions now have more value than carbon reductions in the future. The next couple of decades are critical. This paper focuses on emissions from the built environment and strategies to reduce them, particularly on embodied rather than operating emissions.

Figure 1. Emissions Scenarios
 The following terms are used in this paper:
Carbon, Emissions and Greenhouse Gas emissions are used interchangeably and all refer to Green House Gas emissions (GHG) which are made up of Carbon Dioxide (CO2) and other GHG’s, all of which are expressed as Carbon Dioxide equivalents (CO2e).
Embodied Carbon (eCO2): GHG emissions from materials and construction.
Operating Carbon (oCO2): GHG emissions from building operations — heating, cooling, lighting, plug loads.

The built environment as an end user of fossil fuels is responsible for more emissions than any other sector. These emissions include emissions from building operations, (including electricity generation) and embodied emissions from materials and construction.

While constructing and operating buildings is responsible for almost half of U.S. GHG emissions, it also offers significant opportunities for reducing those emissions. The current gold standard for reducing emissions from buildings is to build new, net zero energy (NZE) buildings — very efficient, buildings powered by renewable energy sources, where the energy generated is equal to the energy needed to operate them. Because we build a lot of buildings, this is a critical piece of getting to a carbon neutral built environment. But there are two problems with relying on this strategy alone — building all of those new buildings will generate a lot of emissions and most building emissions come from less efficient existing buildings.

Figure 2. Consumption by End User Sector
Note: although energy use and GHG emissions are not the same, on a national scale, percentages for energy consumption and GHG emissions from buildings are roughly equivalent.
We need strategies that can produce large savings quickly, and because some reduction strategies result in an initial increase in carbon emissions from materials and construction — we need strategies that can produce net reductions within the next critical 10-30 years. Ultimately, we will need a built environment that is carbon neutral.

Ideally, all new buildings should be net zero energy (and emissions), but once buildings have eliminated operating emissions, two other sources of emissions become more important in the short term:

  1. Embodied emissions from building materials, and construction processes.
  2. Operating emissions from the existing buildings we already have.

NEW BUILDINGS: The importance of embodied carbon emissions (eCO2)

When we started to really pay attention to energy efficiency after the first global energy crisis in the 1970s, we were focused on saving energy, not reducing GHG emissions, and embodied energy and their associated emissions were generally ignored. This was because over a building’s lifespan, typically 75–100 years, embodied emissions only accounted for 10%-20% of a building’s total emissions. But a couple of things have changed since then: GHG emissions have become more critical than energy; and as buildings have become more efficient and operating emissions have dropped, embodied emissions now make up a much larger percentage of total lifetime emissions. Embodied emissions are also important because of when they occur—they are the first emissions from a new building. When a building is constructed—before it starts operating and generating operating emissions—it is already responsible for tons of GHG emissions. And even though the majority of embodied emissions happen once—when the building is constructed—and operating emissions happen over time and are cumulative, the majority of GHG emissions for the first 15 – 20 years of a building’s life will be the embodied emissions from materials and construction. If we succeed in making new buildings net zero energy (NZE), then the only emissions will be the embodied emissions. In the long run, it’s still important that new buildings be NZE, but in the short term we need to focus on reducing embodied emissions.

This is not a simple thing to do. We know how to make NZE buildings, but it is much more difficult to reduce embodied emissions to zero. There are immediate steps we can take—reducing the quantity of the materials in our buildings and selecting materials with lower carbon footprints—but modern, industrial materials generate significant GHG emissions in their production. Ultimately the modern material economy will need to become a carbon neutral material economy. 

Monday, May 1, 2017

McClellan Ranch Preserve Environmental Education Center is Marvin Architects Challenge 2017 Best Commercial Winner

McClellan Ranch Preserve Environmental Education Center | Photo by David Wakely
McClellan Ranch Preserve Environmental Education Center. Photos: David Wakely

 The McClellan Ranch Preserve is located on a ranch dating back to the 1870s that has become a park hosting the City of Cupertino’s environmental education programs. Students gather at the new Environmental Education Center before heading out to the 18 acre park to observe, gather data, and perform experiments.

The new Education Center houses classrooms, exhibits, a library and offices designed to work in concert with the sites historic buildings to shape an outdoor activity for large groups. The building connects directly with the farm setting and careful attention was paid to the unique location and presence of birds living on the preserve. Marvin partnered with Siegel & Strain Architects to specify patterned bird-safe glass for the windows to prevent collision.


Siegel & Strain Architects was recognized as the winner of “Best Commercial” project in Marvin Architects Challenge 2017. The jury praised Siegel & Strain and the design team for the careful thought that went into designing the Education Center so that it fit seamlessly not only into its environment, but complemented the historic buildings already there. The design choices, evident in material selection, colors, and form skillfully connect the new Environmental Education Center to the site. “The expression of the wood rafter tails and patio cover construction is incorporated at the interior by the use of complementary wood windows and doors making this building a clear winner.”

Read the article here.

Tuesday, April 11, 2017

"Carbon Is Us"

The featured image is Siegel & Strain’s work for Bishop O’Dowd High School in Oakland, CA. The Center for Environmental Studies is a net zero energy project. Photo by David Wakely.


A response to William McDonough's new language of carbon.

By Guest Contributors Henry Siegel, FAIA and Larry Strain, FAIA
published in The Urbanist on April 4, 2017

“We’re made of star stuff.” –Carl Sagan

“We are stardust.” –Joni Mitchell

Carl and Joni got it right. So does William McDonough when he says that carbon is not the enemy (“Carbon is Not the Enemy,” in the journal Nature in November and referenced in Blaire Brownell’s “William McDonough Reconsiders Carbon and Its Misuse,” in Architect the same month). Carbon is, after all, a basic component of all life on this planet. His “new language of carbon”—distinguishing between fugitive, durable, and living carbon—challenges us to rethink what carbon is and how we might work with it differently. McDonough correctly points out that carbon negative is a positive and we should start calling it that. (Fugitive is an interesting word choice for unwanted carbon. The first definition of fugitive—“a person or thing that has escaped”—makes sense. The second definition—“fleeting and quick to disappear”—is, unfortunately, not the case for atmospheric “fugitive” carbon.)

He is also correct to call out carbon offsets. We need to plant trees and convert fugitive carbon to living and durable carbon, but not as a justification to continue making more fugitive carbon. Finally, he sets the bar at the top: “Just stop it. Don’t offset it. Carbon dioxide in the atmosphere is like lead in a river, right? You don’t put lead in rivers. You don’t start saying, ‘I’m going to reduce my lead in the river by 20 percent.’ You stop it.

New buildings, he says, should all aspire to bring forth “a delightfully diverse, safe, healthy and just world with clean air, water, soil and power.” Who wouldn’t want that? Architects have made progress, but we still fall short of this goal and thinking only about new buildings is part of the problem.

We cannot build our way out of the global warming crisis by relying only on new cutting-edge green buildings. Most of the emissions from the built environment come from operating existing buildings, so one important strategy is to upgrade and reuse existing buildings—and build fewer new buildings.
Reuse recycles the durable carbon that is tied up in building materials and reduces the need for constructing new buildings and manufacturing of new materials with their associated fugitive emissions. Efficiency upgrades, powered by renewables, reduce fugitive carbon emissions from operating our existing and inefficient buildings. 

Another important strategy is reducing embodied carbon—the carbon dioxide emitted during the manufacture, transport, and assembly of building materials. Carbon emissions have a time value; embodied carbon is front end loaded: It ends when the building is occupied (except for upkeep), while operating energy starts with occupancy and continues at a steady rate throughout the life of the building. As buildings use less and less energy to operate, carbon emissions embodied in building materials and construction become a larger part of the fugitive carbon equation. Over the next 20 years—the critical period for reducing the adverse effects of climate change—embodied carbon will be responsible for most new building emissions. 

The built environment is, as we all know by now, responsible for 40 to 50 percent of “fugitive” carbon emissions. What’s missing in McDonough’s redefinition is the sense of urgency required to really act on climate change, since we are on track to hit a global tipping point in the next 10 to 20 years. Given that timeline, we need to do everything we can. Actually, less bad is good.

We can’t wait for the economy to be reinvented. We don’t have a century to get to carbon positive. We need large reductions in carbon emissions now. By all means, let’s encourage and hasten transformational, paradigm-shifting change. But we also need incremental, obvious, “we already know how to do this,” change right now.

Read the article on The Urbanist website.

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.