Another Green Roof In GR

July 23, 2007
| By Pete Daly |
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GRAND RAPIDS — Bear Manor Properties will break ground in August on a new mixed-use building at 1015 Wealthy St. SE, which will have a "green roof," a permeable parking lot, and other features that protect the environment and reduce energy costs.

The new building, which should be completed this winter, is just one of the latest examples of a burgeoning green construction trend in West Michigan. The project will be submitted to the U.S. Green Building Council for Leadership in Energy and Environmental Design certification.

The roof will literally be green — planted with sedum, a hardy plant that can withstand drought but also absorbs rain quickly and releases it gradually back into the atmosphere, rather than letting it run off the roof and into storm drains.

Barry VanDyke of Bear Manor Properties and the architect for the project, DTS + Winkelmann LLC, are planning a two-story building with 2,000 square feet of commercial lease space on the ground floor and two 1,000-square-foot residential units on the top floor. The building will be framed in steel and wood, with low maintenance cement fiberboard on three sides. The south side, which fronts on Wealthy Street, will use insulated glass that will reduce the entry of direct sunlight but still allow outside views. Awning-style windows on the east and west sides of the residential units will allow for natural air circulation.

The parking lot will be designed to absorb rain and snow melt, allowing water to seep naturally into the earth beneath. Conventional paved parking lots collect water and funnel it into storm drains.

Brian Winkelmann of DTS + Winkelmann said the parking lot will have a paved lane in the middle, but the parking spaces will have a surface of recycled concrete that has been crushed and packed down tight — but not so tight that water can't seep down through it.

VanDyke said his company has renovated a number of older structures but this is its first new building. Total investment in the land and construction will be about $500,000. He said green construction is more expensive, "but a lot of it is making smart choices on materials." He also noted that "if there are ways to make a building with as little environmental impact as possible, that's the way we want to do it."

Bill Stough, CEO of Grand Rapids consulting firm Sustainable Research Group, said a green (also called "vegetative") roof is almost double the cost of a conventional flat roof, yet green roofs have been in use in Germany since the 1970s, and there are large ones now in West Michigan and Chicago. The new Metro Health Hospital in Wyoming has a green roof of sedum and allium plants that is almost 50,000 square feet in area. The Michigan Department of Environmental Quality provided a $400,000 Clean Michigan Initiative grant for Metro’s roof, to help reduce storm-water runoff. The grant also helped pay for bioswales and rain gardens in several of the hospital parking lots.

Chicago City Hall has a green roof, as does a parking structure owned by the city of East Grand Rapids, according to Stough. When completed at the end of 2008, Haworth Inc.'s new headquarters in Holland will have a 10,000-square-foot green roof.

The "pioneer" of green roofs in West Michigan is Bazzani Associates in Grand Rapids, Stough said. The company, which designed the roof at Metro Health Hospital, put a 5,000-square-foot green roof on its own building on Wealthy Street five years ago, the first one in the city. Guy Bazzani said a green roof can add from $7 to $15 per square foot to the normal cost of a roof. That's for a green roof with soil only four inches deep. There are also "intensive" green roofs with soil a foot thick. Green roofs, with the snow and water they retain, can significantly increase the weight on a roof, making structural integrity an issue that could add to the cost.

Despite the additional cost, there are several reasons why green roofs are becoming more popular, said Stough. The first is that they increase the marketability of a lease space.

"There are a growing number of people who want to walk the talk, who believe in an environmental approach to business," he said.

Green roofs are good for the environment because they reduce storm-water runoff that can overload city sewers which, in Grand Rapids, can cause raw sewage to discharge into the Grand River. Green roofs also help reduce the "urban heat island effect." On hot, sunny days, concrete buildings and pavement radiate heat from the sun: Not so the green roofs, as plants absorb sunlight.

There are also some potential long-term economic paybacks.

"Studies indicate there is a significant benefit in energy conservation" with a green roof, said Stough. The added insulation of the soil and plants helps keep the building beneath cooler in summer and warmer in winter.

Then there is the potential of a green roof to extend the life of the flat roof's expensive waterproof rubber membrane.

"Most of the membranes are sensitive to the ultraviolet rays from the sun," said Stough. "By having four or more inches of soil and plants above the membrane, it acts as a buffer against penetration of the ultraviolet rays, so the membrane won't deteriorate as quickly." Heat buildup over the years can also deteriorate the rubber membrane, and plants and soil help keep the membrane cooler. Many flat roofs are traditionally covered with a layer of gravel to help protect it from ultraviolet rays, but the green roof is apparently seen by many as a vast improvement over gravel.

Green roofs "purportedly (make the conventional flat roof) last 50 years," said Winkelmann, but he is quick to add "that is a claim everyone makes" and only time will tell. Stough said the typical flat roof should last 20 to 30 years but "they're thinking a vegetative roof will extend that (to) double."

Bazzani Associates also designed and built the East Hills Center at Diamond Avenue and Lake Drive, occupied by the West Michigan Environmental Action Council (WMEAC) and a restaurant, Marie Catrib's of Grand Rapids. The building has a green roof, and its parking lot is designed with a gradual slope to shunt rainwater into a "rain garden," a sunken, landscaped area planted with several types of selected flowering plants. During heavy rains, the rain garden catches the runoff and holds it until it seeps naturally into the soil.

Shawn Wessell, water programs coordinator at WMEAC, said the 1,350-square-foot green roof prevents 27,000 gallons of runoff from going into the city sewer system each year. The rain garden behind the parking lot is believed capable of capturing up to 400,000 gallons of runoff per year, for return to the underground aquifer, he said.

Urban runoff from roofs and pavement is a serious problem in large cities. According to Bazzani, Chicago and Minneapolis/St. Paul are charging property owners for storm runoff entering city sewers.  

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