Some of the options that exist include:
- Roof replacement
- Water Reclamation
- Permeable paving
Traditional roofing is dark and absorbs the heat from the sun. A sustainable alternative is to replace the roof with either a white or green roof — or even a combination of the two. A white or reflective roof doesn’t absorb the sun’s heat like a darker roof does. Sean Beachy, an architect with Wendell Companies, says they recently worked on a project in which they replaced the client’s roof with a combination white and green roof.
“We also added a photovoltaic array on the roof that would power the entire facility and then we added a vegetated roof that would cover about 18,000 square feet of vegetated roof,” he says. “The benefits to that are it can nearly double the expectancy of their roof system and also it will reduce the amount of dust and things being kicked up into the air because the dust actually gets caught up in the vegetated roof.”
A green roof benefits more than just the building owner, however. The benefits extend to the surrounding community and even the city, Beachy says, “Because one of the benefits of the green roof is it reduces storm water runoff. That storm water runoff isn’t going into the public utility; it’s reducing the burden on that and also for the electricity. They’re not taking power away from the grid, especially during day time when everybody might need it more; so they’re reducing the stress on the local grid.”
The green roof reduces storm water runoff by absorbing a large portion of it.
Adelman says: “From what the plants use from some of the soil, what’scontained there, and even when the water not being used by the vegetation turns into runoff, it slows down that process a little bit. Instead of just having a hard surface, an impermeable surface, where you have higher volume; you almost get a little filtration for that runoff as well.”
“As far as being a public building, having a green roof you can invite the public and educate the public with something so visual like that” says Horton. “There are a number of upsides to green roofs: you get the storm water retention piece of it, you get the insulation factor, and you get the reduction of heat island effect. There are a number of things a green roof in particular does.”
In addition to reducing water runoff through a green roof, water collection is another sustainable option. Adelman explains that storm water mitigation is another big way to reduce the stress put on utilities. “There’s storm water mitigation, things such as using cisterns and doing gray water and capturing rain water, using that for landscaping, reducing the pressure on the potable water, reducing the consumption of the potable water,” she says.
Horton points to The Rapid in Grand Rapids, Mich., as an example of successful water reclamation. “When I talk about water reclamation for a bus wash, I can make the statement that we’re saving 9 million gallons of fresh water per year. That’s a substantial number,” he says.
Horton says that one option is to add a water collection system to the roof of operations and maintenance facilities, which tend to be fairly large. Water collected on the roof could then be used as gray water for flushing toilets and the like. “That building roof is large enough that we could collect a tremendous amount of water,” he says.
Switching from a hardscape — a concrete or asphalt drive — to more permeable pavements allows water to filter to the ground more naturally instead of being diverted into a storm sewer where the water will need to be treated by the local utilities, explains Beachy.