Walls are fundamental to a building’s design—without them, inhabitants are unprotected. Today, design teams are enhancing wall systems and façades by incorporating breathable elements into otherwise-sealed envelopes and embracing high-performance materials. Here, four architects explain how they’re refining their projects’ walls.
Jasen Bohlander, AIA
Leddy Maytum Stacy Architects, San Francisco
Completed in 2012, Leddy Maytum Stacy Architects’ Firehouse No. 1 was the first new firehouse built in San Francisco since the 1970s. The 15,400-square-foot structure required a lightweight wall system that could withstand earthquakes, which the firm met with a souped-up rainscreen. To meet California’s building code for exterior rigid insulation and to avoid thermal bridging via heat transfer from the metal stud framing, the team applied exterior R21 batt insulation continuously. “We pulled the structure, the steel columns, and the diagonal bracing inside the exterior wall, which is balloon-framed so the floor slabs don’t interrupt the framing,” says associate Jasen Bohlander, who notes that some insulation was also used inside.
Marlene Imirzian, FAIA
Marlene Imirzian & Associates Architects, Phoenix
Marlene Imirzian & Associates Architects’ design for a series of new buildings at the Girl Scouts’ 14.5-acre Camp Sombrero in Phoenix takes a common product, Trex’s Transcend composite decking, and uses it uncommonly—as a rainscreen. About 38,600 linear feet of the product is used on the campus, mounted horizontally to vertical hat channels with flashing tape over a vapor-permeable air barrier and rigid insulation, all affixed to the exterior sheathing and metal stud wall.
When considering Trex for decking, firm president Marlene Imirzian says she found it suitable as cladding due to its limited maintenance needs. “It’s a material typically seen as being secondary, but it’s highly durable and does very well in the desert heat.”
Arjun Mande, AIA
Goody Clancy, Boston
At the Upstate Neuroscience Research Building, on the campus of the State University of New York’s Upstate Medical University in Syracuse, N.Y., a 158,000-square-foot expansion clad in a rainscreen of aluminum composite panels contrasts with the original structure’s brick façade. The challenge for Boston-based Goody Clancy was to design a consistent insulation package for both that could stand up to the region’s harsh winters—“a true thermally broken system,” says associate principal Arjun Mande.
The architects designed a monolithic envelope that relies on a continuous air barrier of 3-inch-thick polyurethane foam to achieve an R23 insulating value. Initially, the foam hadn’t been tested with the aluminum panels to the National Fire Protection Association’s 285 standard for exterior non-load-bearing wall assemblies. The architects worked with the manufacturer, BASF, to pass the tests to ensure the system was viable. “It’s a very promising material, and it makes for a high-performing building envelope,” Mande says of the foam. “[But] the … different materials, they all need to work together.”
Heath May, AIA
HKS Architects, Dallas
Dallas-based HKS Architects’ in-house research team, the Laboratory for Intensive Exploration (LINE), collaborates with students at the University of Texas at Arlington’s Digital Architecture Research Consortium to explore how novel materials can enhance wall systems’ dimensionality.
“A skin can be more than just a barrier,” says HKS vice president and LINE director Heath May. “It can be something that’s thermally responsive and a conduit for energy, and [it can] even transmit sunlight.” Fiber-reinforced polymers have gained traction in Europe as exterior cladding, he says. In the U.S., they’ve shown up in applications like the exterior paneling on Snøhetta’s expansion to the San Francisco Museum of Modern Art. HKS has yet to use the polymers (prototype shown above) in a wall system, but May believes the material is ideal for sports stadiums, which is a firm specialty, due to its ability to visually blur the lines among cladding, structural systems, and M/E/P components. “It’s just so amorphous in terms of what it can do,” he says.
This article has been updated to clarify the use of polyurethane foam in Goody Clancy's Upstate Neuroscience Research Building.