Nature Hits the Roof: An Emerging Trend for Environmental, Religious, and Aesthetic Reasons, Green Roofs Can Create an Urban Canopy Sensitive to the Intersection of Architecture and Landscape

Article excerpt

Nestled against the western flank of the Wasatch mountain range, about twenty miles from the Great Salt Lake, the capital city of both Utah and Mormondom spreads over the arid plateau in an orderly matrix of uncommonly large city blocks. At the center of the grid stands the Salt Lake Temple. Six white towers rise amid a cluster of even taller modern buildings that form the heart of the downtown district. And right in the thick of that tightly woven urban fabric is a sight that fools the eye from almost any angle: an enormous, 21,000seat convention center covered with what looks like a vast mountain meadow.

The Church of Jesus Christ of Latter-day Saints, or LDS, is unique among the Christian religious traditions by dint of its theological connection to North America. With an origin in the nineteenthcentury United States, Mormonism is inseparable from the particular places that shaped its history and that continue to serve as sites of pilgrimage. Salt Lake City is its current epicenter. Around the year 2000, it became clear to the LDS hierarchy that the growth of its congregation, which is expanding as rapidly as any other major sect in the world, necessitated a vast new facility near its headquarters. It had to be capable of hosting the tens of thousands of Mormons who would attend the biannual conventions there, yet architecturally deferential to the temple and sensitive to the urban setting it would be altering.

"A building that big, unless it looked like a big basketball arena with a big arena roof, was going to compete very strongly with the natural landscape of the Wasatch mountains," says the Olin Partnership's Susan Weiler, the landscape architect hired to complete the project. "So very early on, the idea was to integrate architecture and landscape--to merge them to be complementary and to take advantage of the natural setting, and not to be competitive or overpower the natural landscape."

The solution was a green roof--or "environmental overstructure," as Weiler prefers to call it--that would generate a raft of benefits beyond the aesthetic. Traditional asphalt and concrete roofs keep the people underneath them dry, but that's just about where the advantages end. They soak up heat during the daytime, only to radiate it back into the atmosphere during what should be cooler hours; they increase the volume of storm water runoff, overtaxing municipal waterworks; they insulate poorly against temperature extremes; and their naked exposure to sun and rain can make repair and replacement costs prohibitive.

The LDS leadership's decision to install a green roof is beginning to look like the leading edge of a deeper religious trend. Recent years have seen the formation of an alliance between environmentalists and evangelical Christians who see "dominion over the earth" as a sacred responsibility. Last September, the National Association of Evangelicals laid out its commitment to environmental principles in clear terms. "We affirm that God-given dominion is a sacred responsibility to steward the earth and not a license to abuse the creation of which we are a part. We are not the owners of creation, but its stewards, summoned by God to 'watch over and care for it' (Gen. 2:15). This implies the principle of sustainability: our uses of the Earth must be designed to conserve and renew the Earth rather than to deplete or destroy it."

Current LDS ground service manager Eldon Cannon believes building a living roof over the new LDS convention center--one that would incorporate a diverse ecology of grasses, annuals, and perennials--was an attractive option for several reasons. "It was a desire for us to see what we could do to be conscious of the heat sink we have here in Salt Lake City ... where the roof is just generating an awful lot of heat," he says, adding that because the roof of the convention center was so large, and because a significant amount of grass would be displaced in the construction process, there was great potential for dramatically increasing the volume of storm water runoff as well. …