Cool, cheap and green: Polystyrene homes catch on in Kenya
30 May 2016, 19:06
Kajiado (Thomson Reuters Foundation) - Justus
Opiyo lives in one of around 50 polystyrene houses in a new
development in Kajiado County, southeast of Nairobi, and says it
has a major advantage over his previous homes.
"Its temperature remains constant, even in extreme weather,
unlike the houses I have lived in before," he said. It is a real
refuge from the heat of the Kenyan summer from January through
March, he added.
This relatively new construction technology, using
polystyrene, is gaining a foothold in Kenya's fast-expanding
housing sector. The panels for building are made of a light
cellular plastic, a by-product of oil refining, which consists
of mini spherical particles containing about 98 percent air.
To make houses, polystyrene foam is sandwiched between two
slabs of steel wire mesh. Once these have been joined together,
they are sprayed with cement to support and strengthen the
The tiny air bubbles trapped in the foam mean polystyrene
houses can control climatic conditions better than buildings
made of timber or concrete. Because air is a poor conductor of
heat, the house stays cool when external temperatures are high
and warm when it is cold outside.
Romanus Otieno, an urban planning lecturer at the University
of Nairobi, said construction with polystyrene is ecologically
friendly as it uses very little water. That advantage outweighs
the negative of polystyrene being derived from crude oil, he
believes, especially in water-scarce urban and semi-arid areas.
For Dennis Muli, an architect with Gem Archplans in Nairobi,
the most important green benefit of polystyrene is its
lightness, meaning less wood is needed to support the building.
That could help reduce deforestation, he said.
LIGHT BUT STRONG
Otieno said a standard two-bedroom polystyrene house costs
about $6,700, while one made of bricks can cost twice as much.
The difference is mainly due to lower labour costs, as
polystyrene is easier to move around and put in place, he noted.
Polystyrene homes are also quicker to build, which could
play a key part in reducing housing deficits, he added.
In Ole Kasasi, a few kilometres from Kandisi where Opiyo
lives in the privately owned housing development, is another
polystyrene building, comprising 20 apartments on five floors.
They are among a raft of polystyrene construction projects
started in Kenya by different companies, including apartments in
the western city of Kisumu built by Malaysian firm Koto Corp.
But the technology has yet to be fully embraced by
homeowners, tenants and other housing developers who remain
sceptical about the strength of polystyrene panels.
Taib Ali, a mason at the Ole Kasasi project, is often asked,
"When are you completing this paper house?" People believe the
homes are fragile because polystyrene can be broken with bare
hands, he added.
Mary Nkatha, who lives in a concrete home near the new
building in Ole Kasasi, has yet to be convinced that polystyrene
can hold the weight of a house for long. She fears it could fall
down, and plans to wait and see how sustainable the buildings
are before she would consider moving into one.
But architect Muli said polystyrene homes are just as
durable as concrete ones, provided the correct procedure is
followed during construction.
Polystyrene has been a major success in countries like
Japan, where it has been used in small dome-shaped homes, he
Muli urged government and non-profit organisations to lead
the way in advocating for polystyrene housing projects because
they are cost-effective and relatively green.
But, as the technology is still new, there is a need for
better workmanship to avert potential problems such as the
collapse of poorly constructed buildings, he said. And there
must also be a focus on how to recycle polystyrene waste from
building sites and demolition, he added.
Koto spokesman Hillary Wesonga said his company had set up a
recycling plant for waste polystyrene. It is not yet a major
problem, as polystyrene construction is only just taking off in
Kenya, but that could change in the future, he added.
Otieno said the cost of building needs to be reduced if
polystyrene construction is to become a popular building method
in Kenya. The polystyrene panels currently cost $21 per square
metre, but the price should be halved to entice more home owners
and developers, he said.
"The essence of affordable housing is to make sure the poor
get basic shelter and there is decongestion (of urban areas) -
what is the point of building more houses that are economically
out of reach for the poor?" he asked.
In addition, building policies in general should be reviewed
so that contractors are obliged to incorporate green features
such as rain-harvesting and harnessing natural light, he said.
And they must ensure the security and safety of buildings,
especially at a time when natural disasters are increasing in
line with more extreme weather linked to climate change, Otieno
In late April, during a heavy downpour, around 50 people
died in the collapse of a residential building in Nairobi, which
had already been condemned but was still occupied.
(Reporting by Benson Rioba; editing by Megan Rowling. Please
credit the Thomson Reuters Foundation, the charitable arm of
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trafficking, corruption and climate change.