Page 32 - ARUBA TODAY

A32 FEATURE
Monday 11 SepteMber 2017
Dutch engineer aims high with latest green roof design

By MIKE CORDER
Associated Press
AMSTERDAM (AP) —
Standing between raised
beds of plants on top of a
former naval hospital, Joris
Voeten can look across to
the garden, cafe and ter-
race that decorate the
sloping roof of Amster-
dam’s NEMO science mu-
seum.
Such productivity is part
of the urban engineer’s
vision for cities worldwide,
places where he sees the
largely neglected flat tops
of buildings doing more
than keeping out weather
and housing satellite dish-
es.
Voeten, of Dutch compa-
ny Urban Roofscapes, says
a rooftop garden system
he unveiled Friday on the
former hospital roof stores
more rainwater than ex-
isting green roofs and re-
quires less power by rely-
ing on a capillary irrigation
system that uses insulation
material instead of pumps
to water plants.

In this photo taken on Tuesday, Sept. 5, 2017, Joris Voeten inspects the rooftop garden he helped
develop in Amsterdam. Associated Press
“You can relax here, you the central Netherlands, can be laid on any flat
can have meetings here. said the cooling effect is roof with sufficient load-
You could operate a res- well known, but the new bearing capacity, Voeten
taurant on your rooftop roof in Amsterdam is an said. Costs would likely
garden to make it more improvement on existing be around 100-150 euros
economically beneficial,” designs because of the ($120-180) per square me-
Voeten told The Associ- way it stores water and ter (10 square feet), he es-
ated Press ahead of the can feed it back to plants. timates.
official presentation. “But Sensors in the shallow layer Amsterdam, a city built
most of all, we finally get of soil on top of the water around water and its World
to exploit the last unused storage elements monitor Heritage-listed canals, is
square meterage in the ur- qualities such as tempera- keen to have its residents
ban environment.” ture and moisture content. turn their rooftops into gar-
Roofs that are adapted so If the soil gets too dry, ex- dens where possible.
plants can grow on them tra water can be added. To promote the practice,
produce a cooling effect If there is too much water, the city is offers subsidies
on buildings and the air it can be released into the to help meet the costs.
immediately above them drains. “We ask citizens of the city
in two ways. The plants “The smart roof really en- to create rooftops like this.
reflect heat instead of sures that there is evapo- We ask companies to cre-
absorbing it the way tra- ration during, for example, ate rooftops like this,” Vice
ditional roofing sheets do. heatwaves and thereby Mayor Eric van der Burg
They also reduce heat by they cool the surround- said.
evaporating water. ings,” Snep, who is not in- “Not only for water stor-
Voeten said readings volved in the project, said. age, not only for helping
taken on a very hot day “People can sleep well cooling down our city, but
showed a temperature and people can work well also to create extra gar-
difference of up to 40 de- in such an environment.” dens, extra green for our
grees Celsius (72 degrees Voeten says his system inhabitants.”q
Fahrenheit) between his
hospital garden above
the banks of a busy water-
way compared with a roof
covered in black bitumen.
Robbert Snep, a green roof
In this photo taken on Tuesday, Sept. 5, 2017, Joris Voeten
shows people around the rooftop garden he helped develop in expert from Wageningen
Amsterdam. Associated Press University and Research in