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Until fairly recently the mention of a “green roof” elicited
for me a mental image of Al Johnson’s famous restaurant in Door County. The
sloping roof of that rustic log building sports a plush lawn with a small herd
of goats casually munching on it. It is unabashedly romantic tourist bait. It
is also a far cry from the technologically sophisticated contemporary green
roof used to mitigate stormwater runoff in urban areas that are increasingly
concerned about environmental sustainability.
I was introduced to green roof design by Peter, the Chief of
Design Integration at a company that specializes in them called Hanging Gardens.
The company is located in Milwaukee’s Global Water Center and we were standing
on the spongy surface of its roof overlooking the Menomonee Valley. Although it
was mid-summer the first thing I noticed was that the roof wasn’t particularly
green. Instead of grass it was planted with multi-hued varieties of Sedum.
Peter explained that several species of Sedum are used
because they are hardy and easy to maintain. The vegetation was set into a grid
of waterproof containers, a little like the flats of flowers one sees at a
garden shop. The whole array was divided into 12 sections called “slices,” which
represent five different types of vegetated roofs. Some of the sections were as
yet unplanted. One section was packed with what looked like brown sponges, obviously
different from traditional soil that’s used in sod roofs like Al Johnson’s. The
absorbent blocks are made from a combination of organic and inorganic materials
that hold water longer than soil, Peter tells me, and the roots of the Sedum can
grow directly into them.
Green roofs can provide a variety of benefits. Chief among
them are reducing or slowing down stormwater runoff and filtering pollutants
from rainwater. In some locations they can also reduce cooling loads on
buildings, act as soundproofing, save money on energy, and even provide
wildlife habitat or a place for agriculture. A side benefit in urban settings
like Milwaukee is to reduce what’s known as the “heat island” effect. Cities
become hotter than surrounding countryside because traditional building
materials absorb and radiate heat from the sun.
Back in the Hanging Garden office I discover that the
process of establishing the green roof had to weather its own problems. John,
Chief Marketing Officer and company partner, picks up the story. It was his
idea to move the company out of its previous location in the basement of his
home. He was eager to bring his company’s expertise to the new and exciting
enterprise of the Global Water Center.
The first hurdle to overcome was financial. Because a
green roof had not been included in the construction budget, Hanging Gardens offered to help install a green roof that
would become a research project utilizing
grants from MMSD and the Fund for Lake Michigan. The second hurdle
almost stopped the project in its tracks. Pulling up the existing roof revealed
extensive damage from rot. Accommodating the 25 pounds per square foot required
over the entire roof would have been prohibitive. The architects compromised,
however, by rebuilding approximately one fourth of the roof with sufficient
structural support for the test plots.
Green roofs are just one of the types of products and
services Hanging Gardens offers. I am fascinated by a demonstration display of
porous pavement, which is designed to allow rainwater to penetrate into the
ground instead of running into storm sewers. A stream of water pours straight
through without slowing down.
Both Peter and John are keen to show off a product called “GreenGlass,”
a silica-based material that looks like exceedingly fine sand. “The raw product
is dry, granular, odorless, hydrophobic and non-flammable,”
says Peter. It’s also superabsorbent. When contaminants in water and soils come
into contact with GreenGlass it captures them through hydraulic conductivity.
“The dirtier the site, the better it is able to perform,” he assures me. A
little like Depends for an incontinent society, I think to myself.
John points out the second floor
windows towards the freshly landscaped Reed Street Yards. The series of
bioswales installed along Freshwater Way utilize GreenGlass in a controlled
test, he tells me.
John is decidedly bullish on his choice of locating in the
Global Water Center. In 2013 Hanging Gardens became the first company to move
into the incubator suites. He loves what he calls the synergy of the place,
making connections not only with other people within the building but also with
visitors who come from all over the world. He remembers when delegations from
France, Germany, and England all came to visit in the same week. Then there was
the time he went to a luncheon with a delegation from China, the CEO of Rexnord
and the president of the Greater Milwaukee Committee. “That wasn’t going to
happen in my home basement office.”
His enthusiasm also extends beyond the walls of the Center
itself. On one side is Walker’s Point, which he observes is “the hottest area
[in Milwaukee] for growth right now.” On the other side is the Menomonee
Valley. “It’s incredible to have offices overlooking the Reed Street Yards and
watching them being redeveloped,” he tells me. “We look out over the Sixth
Street Bridge. I can see the Potawatomi hotel going up, the Harley Davidson
Museum—the whole valley. It’s just very exciting to be in the middle of all
this.”
“My ultimate goal is to have our company in a building over
there,” he concludes, pointing again to the Reed Street Yards. “The valley has
changed dramatically. There’s a lot of opportunity here and it’s exciting to
see the possibilities. There are obstacles, too, because there are brownfields.
But Hanging Gardens can help with some of those issues!”
This post is one in a series that
relates to my Menomonee Valley Artist in Residency. For more information about
the residency and links to previous posts and photographs, go to MV AiR.
