06/07/2009 05:12 am ET | Updated May 25, 2011

Rainwater Toilets and Slag: Touring Berkeley's Greenest Building

This week I got a private sneak-preview tour of downtown Berkeley's David Brower Center, a bold new 50,000-square-foot experiment in "green from the ground up" architecture that will open to the public on Sunday, which is Mothers Day, which makes sense if you think of it in a Gaia/Pachamama/Demeter/Mother Nature sort of way. Four stories tall, the center comprises offices, conference rooms, public space, an art gallery, theater, organic restaurant, and more. Designed to be 40 percent more energy-efficient than standard commercial buildings -- with innovative heating/ cooling/ventilation/earthquake-protection systems and recycled goods infusing its walls, carpets, furniture and fixtures -- it's expected to receive LEED Platinum, the highest certification, from the U.S. Green Building Council. A whopping 53 percent of its construction entailed recycled materials, which makes the Brower Center ... the world's biggest scavenged building.

On its ground floor, executive director Amy Tobin showed me some salvaged-wood tables, benches, and a lustrously smooth black-acacia countertop created by Paul Discoe, an ordained Buddhist priest whose Oakland-based company, Live Edge, utilizes lumber from urban street trees that have been cut down due to storm damage, disease, and other reasons.

The center's soaring concrete walls include up to 70 percent slag. Runoff from the steel-smelting process, slag was long unwanted but is now hailed for its fortifying properties and its ability to help concrete bear weight. The presence of slag in construction also significantly reduces CO2 and cement content.

The ground-floor reception area is set into a geometric grotto whose walls, in bands of varied browns, are a mixture of plaster and salvaged soils. It's a permanent art installation, dubbed "Earth Niche" by its creator, Marisha Farnsworth, whose company The Natural Builders specializes in construction with such substances as earth, cob, and salvaged straw.

"We think of the Brower Center as more 'art' than 'building,'" Tobin said.

Ever since planning began in 2000, the process has focused on sustainability, from methods to materials. The resulting structure boasts a daylighting program that employs zinc siding and photovoltaic panels that double as sun-shades so that, optimally, artificial lights need never be used during daytime in many parts of the building; high-efficiency lighting with automatic controls limit use when daylight is adequate. Windows that actually open and close (a rare sight in office buildings) and low-pressure ventilation via a raised floor system increase indoor air quality. Radiant heating and cooling operate via tubes set into the concrete structural slabs. Non-toxic fabrics and finishes are used throughout. Upright steel cables create a "self-healing seismic system" designed to protect and preserve the center during an earthquake; much of Berkeley is built atop a fault. An interactive real-time systems-monitoring dashboard, set to be mounted in the lobby, will allow passersby to monitor the building's energy consumption.

Interface FLOR carpeting, which includes the industry's highest percentage of recycled content in both the pile and the backing, is used throughout the center. While it runs wall-to-wall in some areas, in others it is laid in tile form, with each small square separately detachable. So in the event of a spill or stain, the whole rug need not be ripped out of a room and replaced: rather, just a tile or two.

Restrooms are a building's "private parts," and the counters in the Brower Center's restrooms largely comprise chunks of recycled glass. The water in the toilets is repurposed too: Faintly yellow, it looks like you-know-what, but it's really rainwater, collected in a cistern. "Toilet water," Tobin reasons, "doesn't have to look drinkable." (Elsewhere in the building, a chain fashioned from recycled bits of artillery shells is used to channel rainwater into a vessel, where it is saved for re-use. And water isn't an issue at all in the men's-room urinals, which are Berkeley's first waterless urinals.)

"In trying to build the right way," Tobin says, "we're trying to send a message here, to establish a track record and a model so that other communities can see how it's done. We're setting a standard. We need to change how we build cities."