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Material witnesses

We profile five masters whose work testifies to the extraordinary ways in which stone, concrete, biology, wood, and glass can render fabulous results.


Rock climbing

by Cliff Gayley FAIA


Recalling our climb to the top of Zervreilahorn, the 9,500-foot peak overlooking the Vals quarry in the Swiss Alps, I appreciate what makes Jim Durham of Quarra Stone a unique force in the world. A stone supplier without a quarry and no particular stone to market, Durham combs the globe for new variations and sources. He is a consultant who can do as well as teach, a fabricator with a forte for computerized cutting and shaping. Exuberant and thoughtful, curious and proactive, he is focused on listening to and acting on the goals of architects who seek him out. “I think stone is different from other materials,” he says, “because it is more of a place; it is a holder of meaning and of history.”

Our path to Zervreilahorn began in 2002 with the defining moment in our firm’s design of two new residence halls for Swarthmore College. It happened when we saw-cut a piece of Wissahickon Schist, revealing a hidden vibrancy within the split-faced rubble stone that defines the college’s all-stone campus. The exposed grain of this metamorphic stone was both age-old and vividly contemporary, with lively waves and swirls, a graphic interplay of white on gray celebrating the natural variations and color range hidden within. Frankly, we loved it. Curious whether this new expression of campus stone could allow our contemporary design to engage with more historic structures, we asked Durham a burning question: Can we find a nonrubble metamorphic stone that captures this grain in taut, square-cut courses? It seemed like an impossible question, one that local quarries could not answer.

Durham embraced our query as an ongoing conversation, listening and probing, sampling known sources and seeking out new quarries, eventually finding an intriguing Swiss quartzite that looks remarkably like the saw-cut schist. Bringing into the conversation Truffer AG (a family-owned quarry in the remote town of Vals, Switzerland), Durham orchestrated a period of due diligence, including quarry visits with full-scale stone mock-ups that we used to test the mix of stone, its range, and its randomness. “I love these moments,” he said with a laugh, “working with people who are ridiculously demanding, with people who have ‘not good enough’ in their vocabularies.” Conversations about randomness would erupt: How much variation is necessary to capture the naturalness of stone? How much randomness is too much? How do you achieve randomness without creating pattern, while managing a color mix from boulder to slab to cut pieces on pallets? Nerdy stuff for sure.

Without a strong sense of teamwork, these strategic conversations would have worn out our stakeholders. This is where the mountain comes in. There is nothing like a nine-hour climb, with ropes and everything, to bring representatives from the college, the contractor, Quarra Stone, the quarry, and the architects toward a common purpose. Even the town joined in by loaning our group climbing helmets, jackets, and hiking boots. “It is all about building trust,” Durham says.

Jim Durham: Stone “is a holder of meaning and of history.” Photo: Courtesy Jim Durham/Quarra Stone Company. Background: Swarthmore College Unified Science Center. Photo: © Jeff Goldberg/Esto

Looking back, he considers the project a watershed, defining a new “architect-centered” focus for him, repositioning his business model around change and innovation—whether chasing randomness at quarries worldwide, deploying computer robotic shaping tools to achieve complex curvatures, exploring translucency in stone, or applying the lessons of biomimicry. On the peak of Zervreilahorn, I told Durham that considering all his technical expertise and access to resources, what I appreciated most was his ability to really listen. “There is,” he replied, “no better compliment.” ■

CLIFF GAYLEY FAIA is a principal at William Rawn Associates, Architects.


Pouring it on

by Mimi Love


“For me, figuring out how to build things is more interesting than designing them.” Listening to Shawn Keller talk about wonky topics such as “fabrication tolerance modeling” can be fascinating. He clearly loves what he does; you can see it in the way he lights up when discussing different fabrication approaches. “Problem solving is the fun part.” His father, Charles, started CW Keller in 1974 in the basement of his house. The younger Keller grew up in his father’s shop and was always surrounded by tools. His passion for problem solving must run in the family.

I met Keller in 2008 while working on the Boston Harbor Islands Pavilion on the Rose F. Kennedy Greenway, long before digital fabrication was trendy. Along with Turner Construction, our firm was excited by the challenge of building this unconventional concrete structure — the first permanent structure on the Greenway.

The pavilion comprises two poured-in-place concrete roofs with complex curves. The roofs are designed to shed water from an upper roof onto a lower roof, and end in a tightly pinched scupperlike form that flows into a sculpted stone catch basin, much like the spout of a pitcher. We were interested in making the concrete roof structure appear as thin and lightweight as possible. We were also set on the roof being a poured-in-place structure to achieve a monolithic reading, as opposed to precast concrete composed of multiple pieces. This presented several technical challenges. We needed a digital fabricator, and that’s where Keller came in.

CW Keller is a shop known for its early proficiency in linking Rhino modeling with computer numerical control (cnc) milling. His shop was also getting good at forming machined curved surfaces out of layers of plywood. Keller was psyched about taking our 3-d model and figuring out how to divide it into individual panels that could be assembled in the field to form the continuous complex curved surfaces of the two roofs.

Shawn Keller: “Problem solving is the fun part.” Photo: Courtesy Shawn Keller/CW Keller & Associates. Background: Boston Harbor Islands Pavilion. Photo: Chuck Choi Architectural Photography; courtesy Utile

The underside surface of the roof was what we cared most about — it had to be as smooth and seamless as possible. Keller recognized that the plywood had to be extra thin (¼ inch) to take the shape of the curvature; however, the tightly pinched scupper went beyond its bending tolerance. This is where Keller combined several vertically stacked plywood sheets and carved them to the shape described in the 3-d model. A series of wood ribs were then created to support the plywood sheets and take up the difference between the bottom of the curved surface and the top of formwork staging.

The design-fabrication collaboration allowed for a level of scrutiny and coordination that included defining the seam layout and identifying the location of screws to form a pattern. Although pouring the concrete in a single pour (yes, you have only one shot!) had its own challenges, I would argue that the formwork was the key factor in making it all come together.

Keller has further refined this fabrication tolerance modeling to much larger-scaled projects, including a concrete house designed by Steven Holl and the Sixth Street Viaduct for the City of Los Angeles designed by Michael Maltzan and hntb. What is most amazing about Keller is his ability to take a simple concept and think about the appropriate medium (plaster, concrete, wood) to determine the best way to fabricate it— and to have the confidence that anything can be realized. ■

MIMI LOVE is a principal at Utile.


Natural selection

by Carole C. Wedge FAIA


One of my first architectural impressions as a child was Buckminster Fuller’s dome in Montreal. Having always had a soft spot for it, I was drawn to a video of students conducting a laboratory experiment to see if silkworms could be used as biological printers to create the infill structure of a dome. That team is led by mit Media Lab’s Neri Oxman, whose research group focuses on material ecology, which considers computation, fabrication, and the material itself as inseparable dimensions of design.

Watching the team shepherd thousands of silkworms and seeing the poetic pattern created by the insects’ efforts sparked my interest in Oxman’s work. Where a typical design effort might start with context and budget, her methodology takes materials exploration to a new level: Products and buildings are biologically informed and digitally engineered by, with, and for nature.

When I met the Israeli-born Oxman in 2014, I was inspired by her evolution from architect to scientist; in 2016, I realized she was further pushing the boundaries of design when her keynote address at the aia National Convention sounded like an aspirational session for nasa Space Labs. Oxman is part guru, part rockstar, and part explorer; she makes the rethinking of materials and processes seem so natural, yet she has had to push through many obstacles and stay restlessly inquisitive in her research pursuits.

Oxman’s thinking is both organic and scientific. She looks at processes in nature to inspire new material considerations, describing her work as thinking about what parameters we need in a material first, then pushing the conversation to a “what if” place: What else could the material do, or what might it provide?

In a recent project, Oxman used chitin—a biological material found in the exoskeleton of crabs, butterflies, and the like—to answer these questions: What would design be like if objects were made of a single part? Would we return to a better state of creation?

She recalls her inspiration to work with chitin. It was 2012, and she was working on the Silk Pavillion, a project of her Mediated Matter group that explored the relationship between digital and biological fabrication using swarms of 6,500 silkworms. Meanwhile, Harvard bioengineer Don Ingber, director of the Wyss Institute, was working on creating a biodegradable plastic from shrimp shells and silk proteins for use in implantable medical devices. “Don handed me a speck of stunning amber-colored material and said, ‘This is shrilk!’ I was flooded with thoughts of tent structures designed to disintegrate by the first rain, returned to sea post-use.” Oxman’s team got to work, ordering shrimp shells from a local seafood supplier and grinding the skeletons into paste. With a custom-made 3-d robotic printer, they created a winglike multifunctional structure out of a single substance, chitosan, which is sourced from the ocean and returns to the ocean: “a true material ecology.”

Neri Oxman: Chitosan is “a true material ecology.” Photo: Noah Kalina, 2017; courtesy Neri Oxman. Background: Fibonacci’s Mashrabiya, 2009, cnc-milled acrylic, urethane rubber, and polyurethane casting resin composites, Museum of Science, Boston; in collaboration with W. Craig Carter. Photo: Courtesy Neri Oxman

Oxman tells me her process starts with science, using observation and testing to understand what natural processes are made of and how they react to their environment. These processes are building blocks that inspire an engineering phase to explore how to make new materials, which then leads to design and the broader cultural context of how these materials might be used.

Thinking about materials as a dynamic system—alive with their properties and at the same time responding to our needs — is the future Oxman and her lab imagine. If architects can evolve our way of selecting materials to a place of naturally aware design, perhaps we can arrive at more insightful solutions for our buildings. ■

CAROLE C. WEDGE FAIA is the president of Shepley Bulfinch.


Grain elevation

by Charles Klee AIA


As a fourth grader, Ron Anthony was asked a familiar question: “What would you like to be when you grow up?” Even at that young age, his answer was characteristically broad and thoughtful. He wanted to be a forest ranger, scientist, or detective. Years later, he found a way to be all three.

After earning a graduate degree in wood science, Anthony pursued a career assessing the performance of wood structures, understanding why wood fails, and ultimately advising architects. His education at Colorado State University was instrumental in setting this course. The program allowed him to study not only forestry but also wood science and technology. “I studied in a program where structural engineers and wood scientists took classes together,” he says. Where many wood scientists looked at careers in quality control within the lumber industry, Anthony wanted to interact with designers and engineers, focusing on the end use of wood products.

When design began on the Harvard Art Museums with Renzo Piano Building Workshop, it was clear that maintaining the context of the historic Fogg Art Museum and Le Corbusier’s adjacent Carpenter Center would be challenging. Selecting wood as a façade material was intended to be sympathetic to the concrete and brick buildings and the residential neighborhood across the street, but the choice raised several technical questions, and our team needed advice.

Ron Anthony: Alaskan yellow cedar was “the key to [the Fogg] façade’s longevity. Photo: Courtesy Ron Anthony. Background: Fogg Museum, Harvard Art Museums. Photo: Clif Stoltze; courtesy Stoltze Design

Recommended by our structural engineer, Robert Silman Associates, Anthony joined the team. He had recognized technical prowess, the intuitive mastery that comes from years of experience, and true passion. Early in his career, he worked with Jozsef Bodig and Frederick Wangaard, among the most respected names in wood science. “They helped me understand performance characteristics, such as shrinkage behavior, far beyond simple numbers in a reference table,” he says.

For the museum project, we needed a species of wood that offers long service life and minimal maintenance. Piano’s team was initially drawn to Siberian larch, but Anthony knew it was less readily available at that time and other species might be more reliably sourced. “Alaska yellow cedar seemed like just the right option,” he says, “because it had the decay resistance and low shrinkage of red cedar with some of the more desirable physical traits of a hardwood.” It was also available as Forest Stewardship Council–certified lumber. So Alaska yellow cedar it was.

Having selected the species, he flipped to the engineering side of his persona and studied how to configure a wood façade for an institutional building in the Northeast. Consistent with good façade design in this climate, he recommended we design the wood façade as a rain screen, but pushed it further. Recognizing the impact of humid summers and severe winter nor’easters, Anthony suggested we use larger timbers with gaps around each piece to provide four-sided ventilation.

He also developed a technical specification for the wood, identifying the optimal moisture levels, a tight vertical grain, and the maximum size and frequency of knots. These requirements were set with a very precise goal in mind. “We knew the key to this façade’s longevity was having wood that behaved naturally within well-defined limits,” he said.

In the five years since the wood was installed, the weathering stain we applied to simulate its aged appearance is wearing off as expected and is being replaced with a natural patina. It’s beautiful, but more important, the system is performing as expected, with very few warped, checked, or split members. To date, no replacement has been required. ■

CHARLES KLEE AIA is principal at Payette, which collaborated with Renzo Piano Building Workshop in designing the Harvard Art Museums.


Beacon of light

by Gary Hilderbrand FASLA


If you know about contemporary design and building, you might be thinking that James Carpenter is the architect or sculptor (which is it?) who works inventively with glass and sometimes with metal. He’s our glass guy, right? Well, not exactly. He’s really our light guy. He practices a kind of fusion with stuff we can barely describe, let alone hold in our hands. I’ve come to see him as an observer, artist, architect, mechanic, environmentalist, phenomenologist, and dreamer.

What I’ve learned from working with Carpenter is that his medium is even more ephemeral than mine. In the landscape, we work with tangible matter: water and earth and plants that are always moving and alive; along with space, which is immaterial and indeterminate. Carpenter’s world is yet more abstract and fugitive because he works with matter in service of energy: light, heat, gravity. Everything he makes is meant to reverberate and refract the sensory information of the life that surrounds us.

If you’re lucky enough to get close, you can barely turn away. A few years ago, Carpenter showed me a digital re-creation of Migration, his 1975 film installation. The piece begins with six projected rectangles that depict salmon moving swiftly through shallow rushing water. Simple enough— though, in fact, the film’s timing is slightly altered with a kind of time-lapse effect by repeating each frame three times. In about 30 seconds, another set of projections appears, showing clouds reflecting off the glimmering surface of the stream, superimposed over running fish. A third set follows, recording shimmers on the stream’s gravelly bottom. It’s an exploded dissection of an activated space in time.

Perhaps you have experienced these transitory qualities in one of his many works, but all this is amplified in a visit to James Carpenter Design Associates’ studio in Manhattan. It’s a Candyland full of materials you’ve never even seen — pickled stainless steel, abraded and corrugated sheets of perforated bronze, toggling hardware and customized fasteners, glass with embedded metal reflectors or prisms, and, of course, full-size mock-ups and experiments in progress. You’re in a wizard shop of applied materials science. Every project invents something the world hasn’t seen before.

James Carpenter: “We need to [slow] things down and [allow] people to see things.” Photo: © Brian Gulick; courtesy James Carpenter Design Associates. Background: Millennium Tower, New York City. Photo: © 2009 Francis Dzikowski/otto

I’ve watched his calm demeanor and persuasive voice bring forward deeper curiosity among clients and collaborators — myself included. He routinely conceives and executes the work with other designers, engineers, scientists, researchers, testing labs, fabricators, and specialty contractors who transport and build with precision and care. The humanist in him draws out in others a greater desire to make people aware of where they are and what it can be like. About working with the medium of light to do this, he says: “So many things in this world today are accelerating beyond the speed of our physical body. Physiology is being superseded by technology. So we need to find ways of slowing things down and allowing people to see things. To see light, see movement, see them-selves, really see the world around them.”

I enjoyed this way of working with Carpenter on the Massachusetts Fallen Heroes Memorial, in South Boston’s Seaport Commons. The 50-foot-tall beacon, perfectly executed in bronzed stainless steel and animated with refracted light and wondrous nighttime luminosity, literally reflects the atmosphere and weather of the Seaport. And it asks us to consider the solemn sacrifice of the Commonwealth’s Gold Star families, who have lost loved ones in Iraq and Afghanistan. The tower, like the artist, defies the usual categories; it’s a refined alchemy of materiality, atmosphere, memory, and awareness of one’s place in the world. ■

GARY HILDERBRAND FASLA, the 2017 recipient of the asla design medal, is principal of Reed Hilderbrand and professor in practice at the Harvard Graduate School of Design.