A sparkling façade for SFMOMA’s new wing
December 9, 2014
Walking past the construction site for the new wing of the San Francisco Museum of Modern Art, the first thing you’ll notice is the façade: the shimmering white panels look a little like waves in the nearby bay. It’s a beautiful effect that was also a technical challenge, with hundreds of unique panels covering over 200,000ft².
For Arup façade engineers Leonie van Ginkel, Felix Weber, and Markus Schulte, the first step was finding the right material for the design. Since the façade includes 700 individually sculpted panels, the engineers needed something that could be molded quickly and easily. In collaboration with the architects and the subcontractor community, they chose glass-fiber-reinforced polymer (GFRP), a material more common in boatbuilding or high-end art installations than in architecture.
“Since we were not reusing these molds, efficiency in mold-making was very important,” explained van Ginkel, who works in our New York City office. “GFRP molds can be made much more efficiently out of Styrofoam, rather than wood, which is typical for a concrete mold.”
As a bonus, the ripples in the lightweight polymer also help make the material stiffer and stronger.
The sculpted panels alternate with flat panels, contributing to the wavelike effect. “The design and construction of the façade required a careful balance between repeating and non-repeating pieces,” Aaron Dorf, Lara Kaufman, and Samuel Brissette, architects from Snøhetta’s design team, said via email. “The unique elements on the exterior are important to help soften the reading of the building and to create various lighting and climatic effects throughout the day and the seasons.”
Each panel is attached to a backup structure that includes a vapor barrier and insulation for the museum. Since the building is humidified for art conservation, it was crucial to avoid any condensation inside. The panels themselves act as a rain screen.
One challenge of the façade’s material — and a reason that it may not have been commonly used in architecture in the past — is that polymer is flammable. The panels had to be carefully designed and tested to prove that they met standards for fire safety.
“The assembly had to be tested as a whole to see whether the panels were safe to be used on the façade of a building that holds multimillion-dollar sculptures and paintings inside,” said van Ginkel. “They all passed the tests.”
A gel coating that protects the glass fibers in the panels from ultraviolet light is mixed with sand to create a shimmering effect in the light. The sparkling finish is one element of a design intended to draw in visitors when the museum opens in 2016.
“As a cultural institution, the building was intended to stand apart from the surrounding context of office buildings and hotels,” wrote the Snøhetta architects. “Its distinctive profile and texture can be seen from a distance, framed by small streets and alleys, which announces the building’s central presence in the city and helps attract people to the museum.”