While Los Angeles-based CO Architects considers all aspects of design during material selection, it focuses on two main elements when it is evaluating building materials: context and performance. Alex Korter, AIA, RIBA, LEED AP BD+C, is a principal and leads the firm’s building façades group. He cautions that that selection matrix may sound limited, but, “I think those are two big elements that will drive selection of a material, including metal, on any of our buildings and any of our enclosures.”
CO Architects approaches metal building materials with a focus on context and performance
Context
“Creating and generating a sense of place of any of our buildings—of any of our envelopes—and tying it to the locale and providing solutions that are very specific to that particular place, that particular time, those particular surroundings, and that particular climate is extremely important,” says Korter.
A wonderful example of context are two buildings done in Phoenix: The Health Sciences Education Building and the Biomedical Sciences Partnership Building. Their forms evoke the nearby canyons, and the striated copper cladding speaks to the geological layering visible in the surrounding topography. But the selection of copper goes further.
“The use of copper has a deep history in Arizona,” says Korter. “It was heavily mined in the area. I don’t want to pretend that the architectural copper came straight out of the mine and onto the building. That’s not reality.” But the influence of copper mining created the context for the building cladding, which fit into the natural landscape.
Performance
The second aspect CO Architects considers is performance. How will that material deliver on the firm’s promise of quality, durability, design excellence and sustainability? “Whether it’s structural, thermal energy performance, daylighting, creating views or protecting the interior function of the building,” says Korter, “this is true to our approach to the use of metal or any other material, to be honest.”
The undulating roof of the Student Services Building, California State Polytechnic University, Pomona, Calif., evokes the nearby foothills, yet offers a superior performance by minimizing solar heat gain, maximizing views, creating a lot of shade and providing the maximum amount of daylight
Korter offers the Student Services Building, California State Polytechnic University, Pomona, Calif., as an example of both context and performance.
“Let’s call it an extreme case,” he says, “but it is an interesting project for us because the dominant geometry is horizontal. It’s about the roof. The vertical walls—which are traditionally the things you would relate to in a façade and a building envelope—are actually on that project quite secondary. They’re are highly glazed, they’re highly transparent. The dominant concept here is the roof. And the shape is driven by the context. The setting in the foothills, the mountains in the background, the topography of the campus. That’s what created that shape.”
There is a lightness to the building that expresses the natural lightness of the metal roof. That has a performance attribute besides placing the building in its setting. “It is shaped to minimize solar heat gain, maximize views, create a lot of shade and provide the maximum amount of daylight. We needed a material that was flexible, malleable and lightweight,” explains Korter.
LEGACY
There is an irony here in CO Architects’ turn toward metal facades and how they make a building feel more weightless. The firm was established by the team that designed the Salk Institute with renowned architect Louis Kahn. Kahn was known for an architectural style that was monumental and heavy. The Salk Institute itself relies substantially on concrete to express its forms and evoke a dominant sense of heaviness, which is a sensation nearly impossible to achieve with metal façades.
Thermal performance of the building envelope is an essential element to achieving CO Architects’ sustainability requirements. An important part of that is shading the building and the Loyola Marymount University Life Sciences Building takes full advantage of the shading opportunities presented by perforated metal screens.
While the metal façades may speak to the lightness of a building, there is still at CO Architects a vernacular architecture where the forms of the building hold to Kahn’s original intent. They are substantial, and Korter is correct in identifying the Cal Poly Pomona student services building as an extreme case. Its lightness expresses the full nature of metal building materials, and the transparency of the walls accentuates that lightness, which makes it different from many of the CO Architects’ projects. That said, there is an aesthetic of context in the building that holds true to the CO Architects’ design philosophy.
On the performance side, there is another reason to make those kinds of decisions. CO Architects is based in Los Angeles and seismic issues are a significant factor in the design and function of its projects. “A lot of our construction is happening in California,” says Fabian Kremkus, AIA, LEED GA, principal. “Building mass becomes a burden to the structure. To build a light skin is kind of paramount if you want to reduce the amount of structure to resist earthquake forces. It’s not just the live load that’s in the building, it’s also the way the actual weight of the building has an impact on how much lateral resistance the structural engineer has to design for. That trickles down to the size of the foundation systems, to steel members, to concrete members or to whatever you make your frame out of.”
Even the copper-clad buildings in Phoenix have a performance and sustainability attribute that goes beyond just energy consumption issues. “Most architectural copper is recycled,” says Korter, “and is actually in a second or even in its third life cycle before it makes it onto the building.” While the decision to clad a building in copper is often based on cost, when the price is right, the material becomes a highly desirable product for both its aesthetic qualities (who doesn’t love the way copper patinas?) and its recyclable content.
The copper cladding of the Health Sciences Education Building and the Biomedical Sciences Partnership Building as well as their cleaved forms suggest the striated canyons in the surrounding areas, while the copper itself gives reference to the history of copper mining in the region.
Palette
When you look at CO Architects’ projects, you see a similarity in the way the metal expresses its true nature. The firm’s buildings tend not to feature brightly coated metal panels, but rely on the natural colors of metal: copper, zinc, aluminum. “I don’t think as a design philosophy, we use solely muted earth tones in our architecture,” says Fabian. “It depends on where the building is and what it speaks to. We always try to give it a sense of place and we will pick the material and the coloration and the use of it.” There are fads in architecture, and often they are driven by palette selection. Vibrant, rich colors one decade. “Kandy-Kolored, Tangerine-Flake Streamline Baby” in another decade. But CO Architects is focused on timelessness and durability in its design. Performance is the second leg of its driving force, and both timelessness and durability are essential elements of performance.
“I think when you look at architecture,” says Kremkus, “it’s when you are able to capture the client’s wishes and give it a sense of place in a meaningful way, even though the aesthetics of the building may date it, a good piece of architecture will always have its merits. When it reacts in the right way to the people and where it is in the city or landscape, good pieces of architecture are timeless. That’s what we’re trying to achieve now.”
Korter speaks specifically to the idea of the durability of metal when talking about the CalPoly Pomona student services building. “We have to remember this as a state school,” he says. “They will own this building for 50, 70, a hundred years potentially, so long-term maintenance is a big, big deal. And we find metal products—metal walls—require less on the maintenance side. The finishes are very durable. Metals themselves are very durable if we don’t finish them. Sometimes, we like to use different metals that will start to patina and protect themselves over time. Like copper, but even aluminum. We’re very interested in that. But that also makes them very long lasting and durable.”
Because of their long-lasting nature, the high embodied content of metals can be offset over time, making them a very strong alternative for sustainable building products. “The embodied content is very high in metals,” says Korter, “and we take that into consideration very carefully. At the same time, the longevity of metal products offsets a lot of the embodied energy problems. It’s a little bit of putting in energy at the beginning, but also having a little really long life span. It’s that constant balance.”
Malleability
The aesthetics of the use of metal at CO Architects goes beyond expressing its natural colors or selecting palettes that fit into the context of the locality. In fact, metal can work against those decisions a bit. “Metal can have sometimes a little bit of a sort of a sterile aspect to it,” says Korter. “The use of metal of a certain color could be used anywhere, could be in any city in any place. So, then we start to look at manipulating that metal. And that’s another thing we like about the material is just the ability to manipulate it. The ability to manipulate it from a geometric perspective to fold it, to bend it to color it to apply textures to it to perforate it. That’s sort of that extra granularity that we then apply.”
CO Architects relies on the use of rainscreens so the metals are expressed as the finished product and cover up a cavity that allows it to place insulation outside the water resistive barrier. It gives the building a better thermally performing barrier. “That’s where the lightness of metal comes in because we’re standing metal off the face of the building. The heavier the material is, the more structure you need to support it. Light metals allow us to make cavity walls that are a little deeper and allow us to put that insulation in there, which creates much better thermal performance.”