An outdoor mural is designed to weather the elements.

The new city hall in Shoreline, Wash., is a model of sustainability, featuring a green roof, recycled-content materials and an on-site solar-demonstration project. But one of the structure's most striking elements, a huge piece of exterior artwork, also turned out to be a surprisingly green design choice.

"Limelight" is a free-form mural, painted on large interlocking aluminum panels, that meanders up the fa+ºade of the elegant, LEED-certified glass and aluminum building. This bold take on a public art project reflects the collaborative spirit between an inventive artist and an imaginative architect.

LMN Architects of Seattle envisioned some kind of art piece integrated with the building and landscaping. Randal Bennett, principal then with LMN, now with ZGF Architects, had been struck by the swirling terrazzo floor of the city hall in nearby Bellevue, Wash. Its creator, artist Linda Beaumont, was contacted and ultimately selected for the commission.

The builders first wanted a work with an evergreen motif. But Beaumont soon changed their minds. "Linda told us a story about taking shortcuts through the woods here when she was a child, and encountering these blossoming dogwoods," Bennett says. "It was a very poetic image."

Beaumont says she was also inspired by the context of the building, which sits on an old highway where billboards and exotic dance clubs vie with remnants of the forest. The Pacific dogwood's fragile blossoms suggest "a longing for a world that's being consumed, disappearing," Beaumont says. She called the project "Limelight," after the green glow of the dogwood buds and to honor Shoreline coming into its own with this innovative civic site.

Early in the project, the architects suggested a work in glass. But funding was limited, and Beaumont also felt a glass art installation would be too dark to be seen during the day. Then Bennett suggested painting straight onto the building. Beaumont was stunned, then delighted. She loved the notion of people moving through the glass corridors alongside giant flowers.

Delight quickly gave way to problem-solving: how to paint something both lyrical and durable. As Beaumont notes wryly, "Given the weather here, we don't exactly do much mural work."

Good chemistry

So how to create a durable, painted mural on aluminum? After a bit of research, Beaumont discovered the answer in nearby Seattle's Museum of Flight. The museum's original contractor, Tim DiBiase of Seattle-based Grund and Company, told Beaumont that on some architectural features, the museum used Kynar, a resin used as a long-life base, top-coated with Sherwin-Williams Bond-Plex®. This combination would provide superior durability.

With its extra bonding agent, Bond-Plex is ideal for hard-to-coat surfaces such as Kynar-treated metal. "It creates minimal odor, doesn't cost a lot, inhibits rust and is fairly forgiving," says DiBiase. And Beaumont was pleased to discover that Bond-Plex is low-VOC (volatile organic compounds). "Sherwin-Williams created a paint that has incredible adhesion and an environmentally responsible formula," she says.

The bare aluminum panels, 10 feet by 3 feet and 5 by 3, arrived around Christmas 2008, and Beaumont went straight to work in her studio. "The construction schedule was tight. Basically, I had two months to cover 1,000 square feet," she says. "I was painting day and night."

For Beaumont, capturing the vibrancy of the blooms was critical. "The blossoms first come out in this luminous lime color. Then they become cream. Then white, with a fruity purple at the center." She found a range of Bond-Plex colors to use (see box), then created some of her own. "Linda came in quite a few times to mix new colors," laughs Britt Osteraa, sales associate at Seattle's downtown Sherwin-Williams store.

Drawing directly onto the panels, Beaumont hoped the immediacy of freehand would suggest the evanescence of the delicate blooms. The sense of floral life exploding into being had to extend across the borders of each metal rectangle. "I didn't want the panels 'interrupting' a flower," she says.

The result is a striking, playful cascade of Wonderland-sized flowers. Bennett says Beaumont achieved "an exceptional result. Linda gave the building a richness of surface it wouldn't have had otherwise."

The success of the piece, to Beaumont, is its simplicity: "For me, 'green' means reining in our ambitions, making do with less. If I'd done this piece in glass, it would have meant going all the way to Germany for the materials. But painting is so simply done. And the guys who make the panels are a couple of miles away. To me, that simplicity is the essence of green."

Colors
Impetuous (SW 6916)
Fusion (SW 6919)
Citronella (SW 6915)
Basque Green (SW 6246)
Lime Rickey (SW 6717)
Organic Green (SW 6732)
Alabaster (SW 7008)
Eminent Bronze (SW 6412)