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It is time to put aside the
“ traditional
roofing concept.”
– Diederik van ‘t Hof, Roof Rats.
(GBCSA) or the International Living Future Institute (ILFI).
According to Solid Green Consulting, the Living Building
Challenge, developed by ILFI, is a green building certification
programme and sustainable design framework.
“Its mandate is to lead transformation towards a civilisation
that is socially just, culturally rich and ecologically restorative.
The Living Building Challenge standard raises the bar for
sustainable development globally,” says Marloes Reinink from
Solid Green.
Adoption of sustainability may also stem from the strain of
water shortages, load shedding as well as increasing rates and
taxes experienced by companies and households alike. Van ‘t
Hof says t hat it is time to put aside the traditional roofing
concept. “A roof structure is a large area. A medium-sized house
has a roof area more than 150m 2 . Sustainability implies a level of
self-sufficiency, and the roof of any structure can help with that,”
he shares.
How to make a roof sustainable
As migration leads many people into the city, big portions of
land are used to construct homes, office space, public facilities,
etc. to accommodate the increasing numbers. A green roof with
flora and fauna can be installed to restore natural plains carved
into. “It is ideal for establishing a buildings harmony with nature.
A green roof increases biodiversity of an area,” says André
Harms, founder and sustainability engineer from
Ecolution Consulting.
A roof planted with various plants assists in the heat island
effect, minimises heat load and provides evaporative cooling
and insulation.
“The bulk of the roof creates a thermal mass that regulates
temperature,” says Harms.
According to Darryn Meisel, national sales manager at
Geosynthetics, rainwater harvesting can be administered from
such a facility.
“We also design these in such a way that they promote
rainwater retention which can be achieved with a deep cuspate
sheet made from High-density polyethylene (HDPE) plastic. This
allows drainage and also retains enough water to support the
vegetation on or in the green roof,” he says.
The rainwater retention additionally cuts down on water use
on irrigated roofs. A roof area with a mass of over 100m 2 can
collect a large amount of rainwater. “A decent rain shower can fill
a five to seven thousand litre storage tank within hours. A short
rain shower can supply a household’s needs for a few days,”
says Van ‘t Hof.
Quality gutters are required to ensure the system works
efficiently. “Gutters and drainage assist with storm water
RESIDENTIAL // COMMERCIAL // INDUSTRIAL
MAY 2018
19