SA Affordable Housing May / June 2018 // Issue: 70 | Page 18

FEATURES
Building beyond
bricks and mortar
SA Affordable Housing has an in-depth look at alternative building
materials currently available on the market and we consider the
pros and cons for the affordable housing sector.
By Dineo Phoshoko with input from Greenlite concrete | Photos by Greenlite Concrete
A flooring screed made from lightweight concrete containing
recycled polystyrene, manufactured by Greenlite Concrete.
W
ith the growing demand for social and affordable
housing in South Africa, exploring alternative
building materials is one of the smarter ways
to reduce the housing backlog and the cost of
delivering homes.
Traditionally, buildings are erected with conventional
bricks and mortar. Although such buildings are reliable and
strong, they are costly and take more time to build and
some of the materials used to build with can be harmful to
the environment.
GET THE GREENLITE
One alternative – Greenlite concrete products – are
suitable for building low cost housing units. These
products are made from 100% recycled expanded
polystyrene (EPS).
The jumbo block and the lightweight aggregate can be
used instead of conventional bricks and mortar. The
lightweight concrete blocks are Agrément SA approved and
have a 2-hour SABS fire rating. The blocks are a good
alternative to conventional masonry as they offer
lightweight walling which is cheap to transport along with
impressive insulation and acoustic performance.
The concrete blocks manufactured with Greenlite concrete
are light, weighing a quarter of typical concrete blocks.
The lightweight aggregate comes in 250 long ton (lt)
bags and is made from recycled polystyrene beads that are
pre-coated with a Greenlite concrete additive. Four bags of
lightweight precoated polystyrene aggregate is mixed with
eight bags of cement, and 240ℓ of water to form one cube
of lightweight screed mix. These screeds offer impressive
weight savings over conventional screeds as well as
combining the screed and insulation application into
one process.
“We recycle post-consumer polystyrene back into beads
through our recycling plants. This material is then used as
aggregate mixed with cement and additives to form
insulated, soundproof, fireproof, water-resistant
lightweight concrete blocks and screeds,” explains
Greenlite’s technical director, Hilton Cowie. The
lightweight material that is not only able to reduce the
structural concrete and steel requirements but offers
excellent insulation ensuring significant energy savings.
ALTERNATIVE MATERIALS AND
THE ENVIRONMENT
Using alternative materials such as recycled EPS not only
has advantages for affordable housing sector, but also for
the environment.
“With climate change looming and the rising cost of
energy, using recycled polystyrene in building and
construction applications is an increasingly popular
solution for architects and material specifiers. Last year
alone, more than 2 036 tons of polystyrene was recycled
countrywide for this use in a wide variety of different
types and sizes of buildings — ranging from schools,
shopping malls, state-of-the-art museums and designer
homes, to low cost housing solutions, schools and
community clinics,” says Adri Spangenberg, director of the
Polystyrene Association of South Africa.
The highly insulated walls from the jumbo blocks have
the added benefit of conserving energy over the lifespan
of the building. In addition, Cowie says that removing
polystyrene from the waste stream has a positive impact
on the environment. “Polystyrene is probably the most
versatile construction material on the market in terms of
carbon footprint. The fact that we only use recycled
polystyrene is even better,” Cowie adds.
See more on page 18.
16
MAY - JUNE 2018
AFFORDABLE
SA HOUSING