Builder Planting Seed of ‘Green Roof’ Design in Jacksonville
Florida Times Union, June 1, 2010
By Steve Patterson
After years of helping customers make their buildings green, Jacksonville contractor Mary Tappouni is showing how to top that work.
She’s building a green roof.
The roof of her construction company — 1,200 square feet of it, anyway — will be covered this summer by low-maintenance plants installed to hold and filter rainwater and reduce heat buildup around the building.
It’s apparently the first green roof on a Jacksonville business, and one of only a few on any type of building in Northeast Florida. “Some people like them because they just think they look cool. And they do, but they also serve a very beneficial purpose,” said Tappouni, the president of Breaking Ground Contracting off Interstate 10 in the Lackawanna area west of downtown.
Tappouni, whose business specializes in earth-friendly construction, was going to rebuild the roof anyway and decided to take some advice from plant experts on how to make it greener.
The roof is part of a bundle of water controls that are planned, including plant-covered “living walls,” a set of swales and a rain garden to catch runoff from pavement.
Together, they’re expected to cut the amount of rainwater leaving the property by 40 percent, Tappouni said, and filter out 90 percent more water pollution.
Plant-covered roofs have gained popularity in North America over the past decade, with municipal agencies from Atlanta to Chicago and Toronto installing vegetation-covered roofs as a statement about making cities more environmentally sustainable.
Green roofs have been mentioned as Jacksonville drafts potential guidelines for water-conserving “low-impact development” construction.
While they’re rare locally, there aren’t that many obstacles to building one.
Green roofing products can be used like any other construction material if they’ve received state approval, said Tom Goldsbury, the city’s building inspection chief. Members of a Florida Building Commission panel that met last month weighed ways to give builders extra credit for energy conservation when they use vegetation-covered roofs.
Green roofs carry extra weight and have to be engineered to handle that, but choices about what kind of green roof to use will determine whether that’s a big factor or not. A relatively simple, lower-cost approach known as an “extensive” design will add less weight than a more ambitious “intensive” design that might feature trees and even fountains that require more support.
Tappouni said her extensive planted roof will be very much like the flat, heat-reflecting white rooftops used on many commercial buildings, but topped with impervious mats with soil and plants. Other extensive designs use varieties of trays to hold plants.
Flowering, drought-resistant sedums and other so-called “fat plants” that catch and hold water for use in dry spells are the species of choice in simple green roofs, which are meant to be low-maintenance.
There will be no irrigation or fertilizer for Tappouni’s roof. After some initial start-up time, roof plants should only need to be checked and maintained every few months, she said. Finding the right plants for Florida projects can be a challenge because the state’s intense heat vaporizes water in soil relatively fast, said Robert Farley, a Tallahassee-based landscape architect. But he said companies that build green roofs nationally see Florida as a growth market where research to adapt to local conditions is ongoing.
Adding a green roof typically costs between $15 and $20 per square foot, according to the nonprofit Low Impact Development Center in Beltsville, Md., which gets federal funding to spread information about water-conserving construction.
The plants also will represent a kind of habitat for birds, insects and other wildlife.
The project was once envisioned as covering the whole roof, but Tappouni said she had to content herself with planting only about half of that area.
The rest, she said, was needed to hold the building’s solar panels.