Sustainability and high design meet in Leddy Maytum Stacy Architects' affordable housing complex.Designing a sustainable building on a budget is tricky enough. But for the Merritt Crossing senior housing complex in Oakland, California, non-profit developer Satellite Affordable Housing Associates upped the ante, asking Leddy Maytum Stacy Architects to follow not one but two green-building ratings systems. "They wanted to push the envelope of what they typically do and decided to pursue not only the LEED rating, but also the GreenPoint system," said principal Richard Stacy. "So we actually did both, which is kind of crazy." Wrapped in a colorful cement-composite rain screen system punctuated by high performance windows, Merritt Crossing achieved LEED for Homes Mid-Rise Pilot Program Platinum and earned 206 points on the Build-It-Green GreenPoint scale. The building was also the first Energy Star Rated multi-family residence in California, and was awarded 104 points by Bay-Friendly Landscaping. Merritt Crossing’s 70 apartments serve low-income seniors with incomes between 30 and 50 percent of the area median. More than half of the units are reserved for residents at risk of homelessness or living with HIV/AIDS. Stacy explains that in the context of affordable housing, sustainability means two things. The first is quality of life for the residents, "the sorts of things that have a direct benefit to the people living there," such as natural daylighting and indoor air quality. The second is energy efficiency. "Both non-profits and [their] residents have limited financial capabilities," said Stacy. "The one time they have funding for that kind of thing is when they’re building a building. So we focused a lot on the building envelope in terms of energy efficiency. At the same time, we wanted to have ample daylight and controlled ventilation.” Finding themselves with unused contingency funds during construction Leddy Maytum Stacy Architects upgraded the exterior skin to a rain screen system of SWISSPEARL cement composite. "We worked pretty closely with the SWISSPEARL company," said Stacy, who noted that Merritt Crossing may be the first building in the United States to use the system. Though the panels are installed like lap siding they offer "the benefits of a rain screen in terms of cooling and waterproofing issues," he explained. To accommodate the thicker skin, window manufacturer Torrance Aluminum designed custom trim pieces, which "had the added benefit of giving us the appearance of deeply recessed windows," said Stacy. Insulation was a special concern for the architects, both because Merritt Crossing was built using metal frame construction, and to minimize air infiltration in keeping with the green ratings systems. The building’s exterior walls are wrapped in 1-inch-thick high performance polyiso insulation from Dow Corning with a Grace Perm-A-Barrier VPS vapor permeable membrane. "As a result we ended up with a very, very tight building from an air insulation standpoint, which means you have to pay more attention to air ventilation," said Stacy. To compensate, Leddy Maytum Stacy Architects’ mechanical engineers designed a special air filtration system for the building’s roof, complete with built-in HEPA filters. The building’s southwest facade faces a freeway, presenting potential noise and privacy issues in addition to exposure to the western sun. "We did a highly layered facade on that [side] where the actual exterior wall is back three to four feet from another screen wall," said Stacy. The outer wall "is a combination of typical wall assembly as well as GreenScreen panels that form a webbing of open areas and solid areas that help with sunshading as well as acoustical [dampening] and privacy." Greenery in balcony planters will eventually grow up and over the screens. On the ground floor, the garage is also enclosed in GreenScreen trellising, to enhance pedestrians’ view without sacrificing ventilation. Leddy Maytum Stacy Architects’ Merritt Crossing proves that affordable housing does not have to look institutional. The facade’s vibrant colors—green on the northeast elevation, red on the southwest—and playful punched texture pay homage to the neighborhood’s patchwork of architectural styles and building uses. The first major building in the planned redevelopment of the area around the Lake Merritt BART regional transit station, Merritt Crossing sets the bar high for future developments.
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A high-performance facade weaves a diverse program into a single volume.The School of Law at the University of Baltimore was founded nearly nine decades ago, but for most of that time its classrooms, offices, library, and clinics were scattered among several downtown buildings. That changed last year, with the opening of the John and Frances Angelos Law Center. Designed by Behnisch Architekten with Ayers Saint Gross, the Angelos Law Center unites a diverse program within a single 12-story structure. Its checkerboard envelope, which won Best Facade in AN’s 2014 Best of Design Awards, weaves the building’s three principal components—a classroom and office wing, the library, and a central atrium—into a single volume. In addition, the facade positions the university on the cutting edge of sustainable design. Its integrated approach to energy efficiency has helped the Angelos Law Center win several green-building prizes, and set it on track to achieve LEED platinum status. Behnisch Architekten took a tripartite approach to the design of the facade. The architects wrapped the portion of the building dedicated to offices and classrooms with an aluminum plate and punched window system. “This is the kind of facade that works very well with the kinds of spaces behind it, because those tend to be a bit more regulated and modular in the way they are allocated,” said partner Matt Noblett. For the library, the uppermost of the building’s two L-shaped volumes, the designers chose a frit glass with a pattern they call a basket weave. “The library, from a program perspective, is kind of a big soup,” said Noblett. There are group study spaces, offices, and, of course, the stacks. “[W]e wanted to find a way in the facade to do [something] more neutral, less specific,” he explained. “The basket weave is less specific in how the articulation of the facade related to the program behind it.” The third segment of the facade, transparent glass enclosing the building’s atrium, draws the two other volumes together. The architects developed a unique sustainability strategy for each section of the building. For the office block, National Enclosure Company fabricated a unitized curtain system comprising the window surface, exterior blinds, and a glass rain screen. The Hunter Douglas Nysan blinds move up and down according to an automated program that operates the top one-third and bottom two-thirds of the windows separately. “It’s remarkable to look at the specific data, to see how much more of the year you’re able to maintain comfort without excessive amounts of air conditioning when you have an exterior sunshading system,” said Noblett, whose firm worked with Transsolar on the building’s climate engineering. Outside the blinds is a low-iron laminated glass rain screen mounted on aluminum brackets. While the architects initially designed the rain screen to protect the blinds, it also solved an architectural problem. “It had a tendency to reunify all of the facade into one building,” he explained. “The more you perforate, the less you read as one volume. By essentially shrink-wrapping [the offices and classrooms], you start to read it again as a [single] volume.” The library at the Angelos Law Center is faced with frit glass from Viracon. “We did a lot of study with the manufacturer” to determine the gradient pattern, said Noblett. “What we wanted it to read was as purely white as possible. We wanted the ceramic as close to the surface as possible.” The goal was to reduce solar gain to the bare minimum. “If you were designing the building and didn’t care how it looked, you would just build a solid wall,” said Noblett. “The idea to add frit to make the wall essentially solid, [but] from the interior of the library it still feels like it’s open.” Outside the atrium, Behnisch Architekten installed a fixed brise soleil by National Enclosure Company on the south and west sides. The north side they left uncovered. All of the Angelos Law Center’s windows are operable, which, while not unheard of, is still unusual in a non-residential setting. “It’s hard to argue with a building where you can get comfortable by opening windows versus sealing up and running the air,” said Noblett. Noblett describes designing a high-performance facade as “this game you’re constantly playing between how much light comes in and how much solar gain [results].” By that analogy, the Angelos Law Center is a check mark in Behnisch Architekten’s win column.
Red-rock mountains and the saguaro cactus inspired the Health Sciences Education Building's rippling copper facade.Downtown Phoenix, observed CO Architects’ Arnold Swanborn, looks a lot like downtown Minneapolis. That feels wrong, given the two cities’ contrasting environments. So when it came to designing the Health Sciences Education Building (HSEB) at Phoenix Biomedical Campus (which won honorable mention for facades in AN’s Best of Design Awards), CO Architects went back to nature—to the Sonoran Desert in particular. “We’re building in a desert. We really, in the outset, wanted to understand what it’s like to build in a desert environment, to really go back and investigate the people who first moved there, or even some of the [American] Indians who lived [there],” said Swanborn. “The skin is really a response to some of the lessons we learned from going out to the desert, being out there and seeing how plants and animals adapted to that environment.” HSEB’s undulating envelope, comprising 5,972 copper panels and more than 10,000 copper parts, echoes two of the defining features of the Arizona desert. First is the omnipresent saguaro cactus, which evolved a folded skin as a self-shading structure. Second is the layered soil of the nearby mountains. “[T]he [building’s] skin folds in a way that’s similar to the saguaro cactus,” explained Swanborn. “How we emulate the mountains beyond is by creating a shadow pattern by folding and articulating the metal panels.” Copper was a natural choice for the exterior cladding. HSEB went up during the recession, said Swanborn, “when everyone was very sensitive to making sure everything was local.” Copper is one of Arizona’s “five C’s”: copper, cattle, cotton, citrus, and climate. In addition, copper is highly conductive, meaning it responds quickly to the region’s aggressive swings in temperature. “Because it’s a rain screen technology we innovated into a sunscreen, there’s a space between the copper skin and building envelope,” said Swanborn. “There’s a 2 ½- or 3-inch air cavity that essentially acts as a chimney. The air gets superheated, and it essentially creates a vertical convection effect, which wicks heat away from the building.” On a 100-degree day, the copper skin keeps the interior a (relatively) cool 70. Finally, copper ages well. “Over time it patinas beautifully,” said Swanborn. “It’s easy to take care of; it kind of takes care of itself.” Phoenix’s climate informed every aspect of the exterior design, starting with the massing. CO Architects worked with Transsolar to determine a shape that would maximize shading. The building is arranged around a narrow courtyard running from east to west, which the architects modeled on the Sonoran desert’s slot canyons. The courtyard is topped with a polytetrafluroethylene (PTFE) shading structure, which “allows daylight to filter through—sort of like a big lightbulb,” said Swanborn. “It filters, diffuses, and bounces off the interior’s light-colored walls.” The courtyard walls are faced in Trendstone ground face masonry units by Trenwyth, a light block rain screen used as a veneer. The courtyard helps bring light to HSEB’s east and west faces, which CO Architects left windowless in order to reduce thermal gain. On the south side of the building, they installed cantilevered copper sunshades over the windows. Vertical copper fins on the north elevation shade occupants from the rising and setting sun. Like the building’s copper cladding, the sunshades and fins were fabricated by Kovach. To open the ground floor on the west end of the building to the adjacent campus green, CO Architects took a cue from early desert dwellers. “When the [American Indians] first settled, they built underneath these carved rock formations, which again becomes self-shading,” Swanborn. The ground floor is glazed, but set back under the building to reduce direct exposure to the sun. Swanborn relished the challenge the joint University of Arizona/Northern Arizona University project provided. “To me the story’s really about the idea of creating a new urban vernacular for the desert,” he said. “The more restricted things become, [the more] architects have to become inventive. The skin of the building is really a pointer to that: it’s inventive, it’s innovative. I think it’s very fitting for that area.”