Jan. 18, 2010, Portland, OR — They
haven’t figured out yet how to get the pruning done, but architects and federal
officials plan one of the world’s most extensive vertical gardens in downtown
Portland – what amounts to a series of 250-foot (76-metre)-tall trellises
designed to shade the west side of an 18-storey office building.
Jan. 18, 2010, Portland, Ore. — They
haven’t figured out yet how to get the pruning done, but architects and federal
officials plan one of the world’s most extensive vertical gardens in downtown
Portland – what amounts to a series of 250-foot (76-metre)-tall trellises
designed to shade the west side of an 18-storey office building.
It is not a new idea to use greenery
vertically as “living architecture,’’ running plants up the sides of a building
to keep it cool. But even in a city with a reputation for rain-fed greenery as
well as for green architecture, the wall of the Edith Green-Wendell Wyatt
Federal Building would stand out.
The architects’ plans call for seven
vertical “vegetated fins’’ to jut at acute angles. The fins would be the metal
framework for planters and the greenery sprouting from them. The west wall is
150 feet (46 metres) long, making the expanse to be shaded about three-quarters
the size of a football field, minus the end zones. The work is part of a $135
million remodeling project, with most of the money from federal stimulus funds. It is
the largest single stimulus project announced so far in Oregon.
The U.S. General Services
Administration says its goal is to create a “landmark high-performance
building.’’ The green wall concept is familiar to anyone who has planted a
deciduous tree or used a vine-covered trellis on the west side of the house: In
the summer the leaves provide cooling shade; in the winter, the bare limbs and
stems admit comforting light.
“If you think about it, it’s a
planter every 25 feet,’’ architect Don Eggleston said. “A lot of people have 10-foot
trellises in their gardens.’’
Eggleston’s firm, SERA Architects,
is working on some questions that weekend gardeners never have to figure out:
what plants will grow readily at more than 200 feet (61 metres) in the air and
how to water, fertilize, weed and prune at that height.
The pruning might be done in much
the same way windows are washed, he said, with workers hoisted and lowered on
platforms. Rainwater collected on the roof, supplemented by city water, will be
piped for irrigating the green wall, he said.
The building is a modernist, international style high-rise completed in 1975 and named for two U.S.
representatives from northwest Oregon. Across from a city park, it is face to
face with City Hall.
It hasn’t gotten a great deal of
respect in Portland. Bart King, author of a local guidebook to the city’s
architecture, said he found it ugly and boring, so he didn’t include it.
It hasn’t aged well, either. Its
precast concrete facade has settled, opening gaps around its single-pane
windows, and it’s leaking air and water, said Kevin Kampschroer, the General
Services Administration official in charge of the greening of the federal
buildings. “It’s not structurally unsound, but it’s not going to get any
better,’’ said Kampschroer.
So, off will come the facade, and
out will come some of the building’s guts. Construction is expected to take 30
to 40 months. Federal workers are beginning to move to temporary quarters.
The General Services Administration,
landlord for federal office buildings, lists other energy-efficient features:
elevators that generate electricity on the way down, solar arrays on the roof,
smart lighting systems that adjust to the daylight available, and using some of
the collected rainwater to flush toilets.
The building’s three other walls
will have less striking treatments: shades on the south and east walls and
windows that drink in the indirect north light.
The building’s roof will stick out –
about 20 feet (6 metres) – and look like a giant mortarboard. The overhang is
designed for shade.
But attention is likely to turn
quickly to the plans for a greened-up west wall. Sean Hogan, writer, nursery
owner and garden designer who worked on a green wall several years ago for the
parking garage at Portland’s airport said irrigation and plant selection will
be critical to keeping a green wall green in Portland’s summers.
Despite its national reputation as a
drizzly place, the city’s climate is Mediterranean, with warm to hot
temperatures from late spring to early fall and little rainfall. Garden irrigation is commonplace.
“Trust me, it will be a challenge,’’ said Randy Gragg, former architecture
critic for The Oregonian newspaper and editor of Portland Monthly magazine. “It
will get baked, absolutely.’’
The idea of vertical gardens has a root in antiquity – the
Hanging Gardens of Babylon, probably near Baghdad, were
in legend one of the seven wonders of the ancient world. Their existence and
extent, however, are in question.
More recently, green roofs have
become established as a way of providing insulation and controlling stormwater
runoff, among other benefits, and green walls have begun to emerge as not only
pleasing to the eye but also part of highly efficient buildings.
At small scale, green walls can even
provide fruits and vegetables, but they are used mostly for energy and
environmental benefits: insulation, cleansing urban air, deadening sound,
and sequestering carbon.
The president of a trade group that
promotes green roofs and walls said the Green-Wyatt installation is likely to
be the most extensive in North America so far. “The GSA has been a real leader
in the use of green roofs and walls,’’ said Steven Peck of Green Roofs for
Healthy Cities. “It’s nice to see the government leading by example.’’
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