‘Living roof’ takes root

Sonoma residents would never know it just by strolling past the La Haye Art Center at 148 E Napa St, but the roughly 100-year-old building has just become home to the first “living roof” within Sonoma city limits.

Jim Callahan, bronze sculptor and resident at the art center, enlisted architect Doug Mighell and the Sebastopol-based company Symbios to help design and install the living roof. The project took three years of planning and nearly nine months of construction.

The living roof, accessible only from Callahan’s apartment, features plants selected to meet both aesthetic and practical needs. “We picked plants that are mostly drought tolerant. We also wanted continuously flowering plants, so there is something in bloom throughout the year,” said Callahan.

Native California plants were also favored in the design, especially those attractive to bees, butterflies, and hummingbirds. Herbs such as sage, thyme, oregano, and rosemary plants have also taken root, and even a small number of young lemon trees. “That’s my indulgence through water consumption,” Callahan joked.

Beyond visually transforming unused space, living roofs offer practical and environmental benefits. The presence of soil and vegetation can at least double the lifespan of a roof by protecting it from UV rays and temperature fluctuations, the principal sources of roof deterioration. “It costs extra in the short-term, but the advantage is that you won’t have to do it again for a long time,” noted Callahan.

Living roofs can also mitigate the rise of urban heat islands by reducing the amount of heat a building absorbs, and thus, the amount of heat radiated later in the day, resulting in cooler temperatures. By the same function, Callahan’s living roof also helps to cool the air in the newly constructed art studio beneath — a welcome advantage on any of Sonoma’s scorching summer days.

Though the garden itself is level, the underlying roof structure is built at a slant so that rainwater can be collected in three 1,000-gallon tanks on the ground floor. “The theory is that vegetative roofs capture up to 60 percent of any rainfall event, so it keeps it out of the storm water system,” explained Callahan. The water that is collected can then be used for irrigation during Sonoma’s dry summer season.

The living roof was made possible by the LaHaye family, the long-time owners of the art center where Callahan has worked since 1979, and lived for the past 14 years. “The LaHayes have been supporters of the arts and this community for as long as I’ve been here—longer than that, even. Maintaining this space as artists’ studios is a wonderful gesture in creating the character of the town,” expressed Callahan.

Now that he has spent some time in his new “backyard,” Callahan says he enjoys the new perspective his rooftop garden offers.

“We’re in a very urban setting here in downtown Sonoma, but from up on the roof you tend to see more as you look around—the treetops and the hills, rather than the sides of buildings,” he said. “For us it’s a living roof, but also a living room. It’s space to be lived in.”

One Response to ‘Living roof’ takes root

  1. Jim Callahan says:

    It should also be noted that general contractor Thomas Bridges of Vision Enterprises played a significant role in the implementation of our plan. We lived in the space while it was being built, not an easy thing for anyone, but Thom and his crew and his choices of subcontractors made the whole ordeal much more manageable. I also appreciate the kind indulgence of our neighbors, who were inconvenienced by the coming and going of all kinds of apparatuses. Looking forward to the rain!