Meyer + Silberberg Land Architects and Concreteworks collaborate on a high-wire ballet of swinging concrete and flowing water.

By Zach Mortice 

Hired to design the atrium courtyard of a San Francisco spec office building that features a canted glass roof that channels rainwater, David Meyer of Meyer + Silberberg Land Architects got a few simple instructions from the building’s architects at Pfau Long Architecture—the most interesting of which was to “do something with the water” that the roof would corral into a cascading stream, dripping into the atrium.

But that simple request kicked off a high-wire adventure that saw a three-ton concrete rainwater cistern installed in the courtyard, pushing concrete fabricators to their limits.

Meyer turned to the specialty concrete fabrication firm Concreteworks to manufacture the cistern at 270 Brannan, built by developers SKS. Meyer’s most important request? The cistern had to be one continuous piece. After delays from the general contractor, Meyer says, Concreteworks was nearly bumped from the project, and substitute fabricators wanted to assemble the cistern from 16 pieces. “This has to be done artistically, as sculpture, not as a fabricated quilt work of GFRC [glass fiber reinforced concrete] that would dramatically change the look of it,” he says. A move to a new production facility meant that Concreteworks could meet the project’s tight deadlines, and deliver a sculptural whole that would define the atrium.

At Concreteworks, founder and creative director Mark Rogero and his team made a custom, two-ton mold out of wood and foam. The molding and curing process cast multiple sections separately, and then joined them while the concrete was still wet. “That’s the magic,” Rogero says. When it was dry, the cistern was polished and honed to a lustrous, dark slate gray shine. At 20 feet long, it was larger than anything they had ever cast before. It was also larger than anything they’d ever craned into a site. Installation would require it to be lifted five stories over the glass atrium and lowered into place with only three inches of clearance on either side. To protect it on this perilous, 45-minute journey earthward, Concreteworks fabricated a half-ton steel cage that had to be cut away when the cistern was lowered back to the ground.

Once installed, the cistern became the visual centerpiece of the atrium; its graceful oval curves contrasting with nearby unfinished logs and rectilinear wood seating. When it rains and water flows into the cistern from the roof, it’s an aural centerpiece, as well. “If it’s foggy, it’s just dripping into the cistern,” Meyers says. “If it’s raining, it’s like Yosemite Falls in there.” Rainwater flows out of the cistern immediately (making it more of a splash pad than a true water-storing cistern) into the planting area, where it waters giant lilyturf and angel’s trumpet. From the cascade of water falling from the sky, to the perimeter of lush, flowering plantings on the ground, the cistern is the courtyard’s hinge that connects the sky and earth.

Rogero says this record breaker will likely soon be dethroned. Clients are approaching him more and more with ideas for larger and larger projects. But the limiting factors most likely to impinge on his next concrete behemoth aren’t technical fabrication constraints; they’re transit regulations. “There are limits of how big things can get before Caltrans won’t let us put it on a truck,” he says. Driven by computer-aided design, landscape architects are asking for more large and geometrically complex shapes, he says, creating a recipe for more white-knuckle high-wire acts in the future.

Zach Mortice is a Chicago-based architecture and landscape architecture journalist. You can follow him on Twitter and Instagram.