When two architects from very different backgrounds and with very different ideas about architecture join forces, the merger of diverse talents can have exponential results, with the sum being much greater than its parts.
The dynamic designs of XTEN Architecture represent just such a fusion of creative forces. Co-founded in 2000 by principals Austin Kelly, AIA, and Monika Haefelfinger, the firm’s work not only melds different architectural styles, but also the design influences of different countries. The firm has offices in Los Angeles and Basel, Switzerland, and is involved in projects worldwide. Buildings in design and construction include several custom residences, galleries, private museums and commercial projects in the U.S. and large-scale buildings in China, the Middle East and Switzerland.
Haefelfinger was raised and completed her initial architectural training in Switzerland, where she worked with Swiss architecture firms for many years. Kelly grew up in Connecticut and graduated from the Yale University Graduate School of Architecture, New Haven, Conn. He became involved in several award-winning projects with the Los Angeles architectural offices of Frank Gehry, Frank Israel and Eric Owen Moss. Haefelfinger and Kelly eventually crossed paths in 1999 when both were designing high-rise buildings in Asia for Los Angeles-based architectural firm DMJM/Keating.
“When Monika and I met, we realized that although we came from different backgrounds, we shared a passion and agreed on what makes great architecture,” Kelly recalls. “One of the things we realized early on was that when we both worked on something, it was better than if either one of us had worked on it alone.”
That spirit of collaboration extended to the founding of XTEN. The “X” represents the idea of a multiplier, as in “times ten.” XTEN’s Los Angeles office employs a team of ten architects, designers and support staff, and the associate office in Switzerland has a staff of four architects and designers. Los Angeles is the home base for Kelly and Haefelfinger, but they travel to Switzerland often to develop and oversee projects. Whether they are working in the U.S. or overseas, their design philosophy is consistent, even though construction requirements and methods may differ.
“The extreme weather plays a greater role in Swiss construction than it does in California, and [the Swiss] are far ahead of [the U.S.] in terms of limiting the energy consumption of buildings,” Kelly says. “The energy codes [in Switzerland] are much more restrictive, and therefore the buildings are much ‘greener’ on average than they are in the U.S. A massive amount of insulation is required for all exterior building assemblies and all glazing is required to have exterior motorized shades to minimize thermal gain.”
Design Aspirations
XTEN specializes in contemporary architecture with an emphasis on refined detailing, open spatial configurations and strong sculptural forms. The firm currently is working on several private residences in Los Angeles, Newport Beach, Calif., and Palm Springs, Calif., as well as urban and multi-use projects in Switzerland. Proposals for high-rise building designs in the Middle East and China also are in the works.
“We are interested in carrying some of the structural, material and patterning ideas we’ve developed in our residential work into some larger buildings. The connections to nature and to the buildings’ surroundings also are very important, and we’re in the process of seeing how we develop that experience from the private scale of a house to the public scale of a city and skyline,” Kelly explains.
This concept of scalability has had a significant influence on XTEN’s designs. “We want the ideas we are developing in our projects to be scalable,” Kelly continues. “It’s important that an idea can be modified to scale up to a tower or down to a gallery.”
XTEN’s contemporary architecture also places an emphasis on what Kelly and Haefelfinger call “material transformation,” or taking a building material and manipulating it in unique and creative ways. They find that metal is the ideal medium for such customization. “We have featured metal in many of our buildings because it can be utilized across a number of different conditions,” Kelly explains. “Other materials that could dilute the design intent are not required and the building can appear as a single, complex idea. Metal also can be fabricated in different ways; bent, cut and welded into form; and detailed very precisely.”
Metamorphoses in Metal
Kelly notes that metal is used extensively in Switzerland for roofing, rainscreen façade systems and custom detail work. In the U.S., XTEN is following the Swiss example and using metal in innovative ways to bring greater identity to its residential and public projects. Three buildings currently under construction in the Los Angeles area—Diamondhouse, Sapphire Gallery and the Macapa Drive house—are notable examples. The first two buildings are clad in laser-cut metal panels with patterns repeated at various scales. The other makes use of exposed steel framing and glass walls to permit optimal views from all directions.
Diamondhouse and the Sapphire Gallery employ metal panels as façade rainscreen elements. Diamondhouse is a private residence in Santa Monica, Calif., set against a sloping hillside. The façade’s diamond-filigree patterning is rendered with laser-cut aluminum panels, which are anchored to the base structure with steel clips. During the day, the panels reflect and refract natural daylight. At night, recessed lighting placed behind the panels allows the building to glow from within like a lantern.
The Sapphire project, a gallery addition in Encino, Calif., is designed to house a growing art collection while providing views of the surrounding hillside gardens. The structure uses a steel-braced framing system to double-cantilever portions of the building off its compact base. Sandwiching the steel frames is a building façade system that protects the art from exposure to the sun’s rays without obstructing the view. The south façade and inclined roof are clad in photovoltaic solar cells arranged in a trapezoidal array, a pattern that continues on the east and west façades of the building as perforated aluminum.
XTEN has incorporated metal rainscreen façade systems on several recent and current projects as a way to transform buildings dimensionally and in relation to their environment. “The layering of materials is interesting to us—for example, laser-cut aluminum panels over glass, or perforated metal that is used to clad walls that recede in space,” Kelly says. “With a layered building, the lighting conditions change the appearance and experience. The building at times appears as solid as concrete and at times appears translucent and glowing. We also have been using structural steel in several recent designs, modifying truss systems to achieve large cantilevers embedded within complex geometries. None of that would be possible with conventional wood or concrete construction.”
The Macapa Drive project—an ultra-contemporary home in Hollywood Hills, Calif.—is an example of structural steel used in this manner. The site has incredible views of downtown Los Angeles and the entire city to the south and west. The client wanted to open the interior spaces to the views and add three bedrooms and master suite on a lower floor.
“Our idea was to use steel-braced framing to minimize the vertical elements needed to support the roof and resist seismic forces and to use a steel-frame roof system with exposed metal decking,” Kelly explains. “It is very much a commercial construction system modified and detailed to fit a high-end residential situation.”
A Greener Future
Although XTEN specifies metal for many of its projects, the firm’s process of choosing materials is a gradual one, allowing for the design concept of a building to unfold before the ultimate selection of a façade or a structural system. “We do not go into a project with a predetermined idea of how it will look or perform, but let that develop out of a rigorously researched and analytic design process,” Kelly says. “The final specification of a material is usually a synthesis of several variables, including performance, aesthetics, budget and construction sequence considerations.”
Another factor important to material selection is sustainability. From the firm’s start, XTEN has incorporated green technologies and materials in its design plans whenever possible. Whether these proposals made it into the final built project, however, largely has been dependent on the client’s budget and preferences. That is beginning to change, according to Kelly. “We’re encouraged to see that the price tag of green technologies has come down and client preferences for integrating them from the beginning of the design process are going up.”
Because of this growing penchant for eco-friendly construction, Kelly sees green building and sustainability as the way of the future. “In all our projects, XTEN looks at the range of possibilities to reduce the carbon footprint of the building, from passive building systems to utilizing recycled-content materials to using renewable-energy sources to serve a building’s power requirements,” he says. “We take great care when we consider and develop the construction of a project, anticipating that the building is going to survive long after we are gone.”
Anne Balogh writes about architecture and metal construction from Glen Ellyn, Ill.