A Green Roof – You May Want to Consider It

111 Third Avenue

Manhattan

Dan Gullick wanted to protect the roof. The board president of a co-op on Third Avenue and 14th Street was convinced that the way to do that was by putting in a green roof. But wouldn’t it be costly?

No, he was told, with grants and energy savings, the payback could come within seven years. And, he learned, there were other benefits: it would extend the life of a roof membrane and increase the property’s value by replacing a tar roof with a “meadow”-like experience.

Gullick got his roof five years ago, and says he hasn’t regretted it. But are green roofs for you? What are the factors – both financial and practical – that you have to weigh when deciding whether to go green up top?

Preserving the roof. “No matter the age of the roof, going green will extend the life of the waterproofing by anywhere from 40 to 75 years; but for maximum financial benefit a newer roof is preferred,” says Amy E. Norquist, founder of Greensulate, a company that installs green roofs.

Cost and energy savings. “In terms of cost, if somebody is putting on a new roof, it’s probably going to be twice the cost on the front end. We do a structural analysis that determines the ‘dead load’ capacity of the roof. We give design/plant options based on the available capacity. If the roof has a lot of available dead load we can include more engineered soil and therefore have more plant choices. If the weight capacity is lower, we go with a simple extensive green roof that includes ground cover plants such as sedum (and even with sedum there are 600 types),” says Norquist. Return on investment can be as low as seven years in terms of energy cost and increased value of the building.

Size. Costs go down as the square footage of the project increases, so larger roofs get more of an economic benefit because they have a larger roof-to-building square footage ratio.

Cooler. The drought-tolerant, succulent-type plants on a green roof absorb water. In that process, the green roof is acting like an air-conditioner. “They absorb a ton of heat and pollution,” says Norquist. “They absorb carbon dioxide. They emit oxygen. They manage storm water.” On the other hand, with “a tar roof up there, the roof degrades faster. It’s hotter. There’s more heat gain into the units directly beneath the green roof.”

Grants. The New York City Department of Environmental Protection (DEP) offers a grant program for private property owners in combined sewer areas of New York City. If selected, DEP will provide funds for the design and construction of the green infrastructure system. For more information, go to http://bit.ly/DEPGrant.