January 13-19, 2005

loose canon

It's Alive!

How much green does it take to put some green on top of a Philly row home? (A lot.)

by Bruce Schimmel

Diane Gentry can't remember exactly when she dropped the dirt bomb on her partner, John Tull. It was sometime in late 2002, and they were already several months into the hell of rehabbing their house on the corner of 20th and Kater.

But Gentry is almost certain that she told Tull about her own, very special plans over dinner at a friend's. That's because the couple always ate at friends' houses. By now the couple had no place at home to eat — except in the basement, on a mattress, under a sheet of plastic where they slept.

"I want a garden on the roof," she remembers telling him.

"Like big planters?" asked Tull, 36, who is a real estate developer for the nonprofit Friends Rehabilitation Program.

"Well, no, planters are not quite big enough," said Gentry, 28, who graduated Bryn Mawr with a degree in political ecology and now writes grants for nonprofits.

After work, on weekends, to the cheers of neighbors, the couple dismantled the old blue fluorescent hair salon sign that hung over their front door. They pried off the pink paneling that stockaded the brick outside.

"So ... a deck?" peeped Tull.

"No. I want a roof garden. A green roof. I want to put dirt on the roof."

Inside their house, the two had discovered rats' nests in the walls and termites in the floors. So timber by timber, they removed the splintering beams of their more than 100-year-old house. By then, their dream home looked like a $172,000 pile of rubble.

Tull couldn't believe what he was hearing. "You wanna put dirt on the roof?" he asked, launching into a litany of why you should never put dirt on a roof.

It's an argument that he lost.

Two years later, having spent over $150,000, they are finally eating in their own home. They no longer walk a plank over a 12-foot drop to get to the bathroom.

In the last two years, 100 tons of ancient trash emerged from their three-story home. "We have the receipts to prove it," says Gentry. Beefy new rafters were installed, along with new utilities and a state-of-the art drainage system for the garden above.

In the next few weeks, the couple will bury a high-tech white plastic covering under several tons of dirt, making it the first Philadelphia row home to be capped with a roof that grows. (Others have done similar things with single homes, but never a row home.)

"From my roof, I look down the block onto squares of black tar that are hot enough to fry eggs on," Gentry says. Instead of baking in the heat of concrete of an urban island, green roofs mean fresher air for all, she says. For homeowners, she cites other benefits.

"It's a super insulator. And you'll never have to put on another roof again. That's because what breaks down [conventional] roofs is sunlight. But plants love sunlight, and they are nature's way of processing destructive sunlight into useful things, like fresh air."

But just how well green roofs clean the environment is still to be determined. Under the heirloom tomatoes, rosebushes and dwarf apple trees that Gentry expects to plant, buried in various layers of fill and soil, sensors have been installed in the roof to measure its runoff. Students from Swarthmore College plan to analyze the data to determine how well the roof filters air and water pollutants.

Having survived the rigors of their aerial money-mound, Gentry reports that she and Tull are still "in love, committed individuals, who haven't killed each other ... yet." Excited by his living roof, Tull is now thinking about installing a waterfall and a pond stocked with koi fish.

The couple is eager to talk to others about installing roof gardens. (You can contact them at dianeagentry@yahoo.com.)

"It's a way to get people to move back into the city. Many baby boomers don't want to give up their garden, yet still want to be near theaters," Gentry says. "They might move to or stay in the city because they've got a garden on their roof. Think of it as a private garden space ... but with no deer."