Ohio State’s First Green Roof Makes Debut

Megan Welsh on Howlett Hall's green roof

COLUMBUS, Ohio -- Ohio State University’s first publicly accessible green roof is open to visitors at Howlett Hall on the campus of the College of Food, Agricultural, and Environmental Sciences.

The green roof, or rooftop garden, is part of the university’s Chadwick Arboretum and Learning Gardens.

The 12,000-square-foot green roof was installed in August and September on the back of Howlett Hall, 2001 Fyffe Court over the building’s extended ground floor. Previously, the roof was accessible through a first-floor conference room, which had been built with a doorway to allow people to step out onto the roof.


Time lapse video, taken Aug. 14 to Sept. 11, 2013, of installation of green roof
on Howlett Hall. (Video by Walter Warkus and Brian Mowrey)

The roof had been meant to house a rooftop garden since the building was dedicated in 1967, said Mary Maloney, director of Chadwick.

“Many people dreamed of getting this done, but Megan Welsh carried the ball over the goal line,” Maloney said.

The green roof is at the back of Howlett Hall, off the first floor, over the Wilbur A. Gould Food Industries Center pilot plant.

Welsh, a certified green roof professional and the project’s coordinator, had attended Ohio State after high school but left before graduating for a decade-long career in film editing in Los Angeles. She returned to the university in 2009 after learning more about global climate change and sustainability, and becoming inspired by the promise of green roofs.

Welsh decided to double-major in construction management and horticulture, and soon met Maloney, who immediately began talking with her about helping Chadwick move forward with Howlett’s green roof plans. Welsh began working on the project as a student and stayed on as a consultant after graduating in December 2011 and opening her own firm, Higher Ground Green Roofs, LLC.

During that time, the university began making plans for the old roof, which was “leaking, blighted, and needed to be replaced,” Welsh said. “We jumped on board with Ohio State’s schedule to place the green roof on top of the new roof as soon as it was installed.”

The green roof offers multiple benefits, including:

  • Lengthening the lifespan of the new roof. “The green roof will save this roof from having to be replaced in another 15 years,” Welsh said. “It protects the roof from the sun and the elements, and will lengthen the lifespan of the roof to 40 or 50 years.”
  • Diverting 200,000 gallons of stormwater runoff each year. “Stormwater runoff is a big problem in areas where there’s a lot of development,” Welsh said. “There’s too much storm water running into drains and it’s polluting our rivers. With a green roof, the water doesn’t leave the roof, because it’s being used by the plants.” In this case, the stormwater runoff is being diverted from the watershed of the Olentangy River, which is just a half-mile away.
  • Reduced utility costs in the summer. A green roof helps deflect some of the heat gain from the sun’s rays during the summer, Welsh said, reducing air-conditioning costs.
  • Increased green space in the urban landscape. The plants chosen for the Howlett green roof are drought-tolerant, allowing them to thrive with little rain to ensure the garden will survive with little maintenance.

As Maloney said, “In a nutshell, on Aug. 12, Howlett Hall had a conventional tar and chip roof, but by Sept. 6 it had a fully planted garden.”

Once the new conventional roof was completed in August, work began on the green roof. First, the new roof’s membrane was covered with a heavy-duty protection fabric, with a lightweight drainage layer installed over top of that.

“We kept the existing drains, so any rainwater the plants don’t use will be drained away,” Welsh said.

Then, about 4-6 inches of lightweight growing medium, engineered specifically for green roofs, was added, mounded in some areas to add interest to the rooftop landscape, along with curved walking paths.

The plants were planted in September and included: Blue Fescue, Geum Tangerine, Coreopsis, Achillea (Yarrow), Black-eyed Susan, Talinum calycinum, Prairie Dropseed, Lavender, Allium cernuum, Sempervivum Black (Hens & Chicks), Thyme (four varieties) and Sedum (18 varieties).

“We may need to make adjustments in the future,” Welsh said. “Some plants may do better than others. But that’s OK, this is a process.”

Chadwick Arboretum raised more than $400,000 for the green roof project, Maloney said. The green roof itself cost about $200,000, Welsh said, plus $100,000 for the new guardrail and another $100,000 in pre-construction design and engineering.

The Columbus area has several other green roofs, including one at the Grange Insurance Audubon Center, Grange Insurance Corporate Headquarters, The Lazarus Building, the Columbus Commons underground parking garage, Franklin County Courthouse and the Dublin Community Recreation Center, but none are easily accessible to the casual visitor, Welsh said. 

 “We really want this to be a demonstration of green technology -- a repeatable example so more people realize they can do this,” she said. “It doesn’t have to cost $2 million to build a green roof. It can be attainable.”

A new entryway to the roof from the first floor of Howlett Hall  is currently being completed, Maloney said, but the garden is open to visitors except during times when work on the entry’s construction periodically blocks access.

For more about the green roof, see the Chadwick website at http://chadwickarboretum.osu.edu and click on “Green Roof at Howlett Hall.”

For additional information or to discuss scheduling tours after the new entry is completed, contact Maloney at 614-688-3479 or maloney.23@osu.edu or Welsh at 614-949-6008 or megan@highergroundgreenroofs.com.



Martha Filipic


Mary Maloney

Megan Welsh