On campuses, Roofmeadow has consulted at the University of Pennsylvania, Temple University, the University of the Sciences, and St. Joseph's. Other projects are in the bidding or construction phase, such as the Cira Green, the Pennsylvania State Police Headquarters, Children's Hospital of Philadelphia Ambulatory Care Center, and Penn Presbyterian Medical Center.
Roofmeadow itself is not the builder, Muroff said.
"We certify and train contractors all over the U.S. to build the green roofs, which we then maintain and guarantee," she said. "We're on site and provide oversight for our warranty guidelines.
"We don't actually build. But because we're on job sites and interacting with contractors with any problems, we are involved in all of those real-time issues."
The folks at Roofmeadow clearly understand costs.
Size predicts expense, to a large degree, and the most economical style of green roof runs roughly $8-$10 per square foot. That is in addition to the cost of the underlying roofing and waterproofing layers, which price out anywhere from $4 to $40 per square foot.
"When developers consider this, they have to install two roofs. They have to put in a liner for a watertight layer on the roof deck, and the green roof goes on top of that," Muroff said. The most economical are projects that are at least 10,000 square feet, she added.
Deeper green roofs, those with meadows, water features, and trees, can cost $40 to $100 a square foot.
"That's similar to what you pay for landscaping on the ground," Muroff said.
That might explain why green roofs are a niche business. However, with the installation of a green roof, "it's entirely possible you'll never reroof again," she said.
Why? What wears out roofing is UV radiation and temperature fluctuations. Green roofs act like a cap, protecting the underlying membrane from debris, but also modulating the temperature of the roof by absorbing heat. As a result, the roof membrane doesn't expand and contract, especially in summer.
Miller has been planting the seeds of this business since 1997, when he founded the company, then called Roofscapes. Miller wanted to introduce green-roof technology for urban stormwater management to the U.S., and he still participates on the advisory committee for the Center for Green Roof Research at Pennsylvania State University.
But Roofmeadow did more work nationally, and very little work in Philadelphia, until about five years ago. Other local Roofmeadow projects include the Peco headquarters building, the Pennsylvania Ballet, the Kensington Creative and Performing Arts High School, and the SAP America headquarters expansion in Newtown Square.
The Philadelphia Water Department has phased in a new billing system for commercial property owners that is based on their workplace's amount of impervious surface - such as parking lots.
That has increased some of the demand for Roofmeadow's green roofs, which can lower the cost for commercial customers by recycling rainwater rather than stressing the sewer system with runoff.