In June 2019, the government
announced its intention to reduce
greenhouse gas contributions to net
zero by 2050 and for the UK become
the fi rst major country to introduce
zero emissions. However, the United
Nations predicts that 68% of the
world’s projected population will live
in urban areas also by 2050. Is it time
to start thinking outside the cement
box?
Cement is one of the world’s most-
consumed resources after water
of which it takes a lot to make. It
provides 8% of the world’s carbon
dioxide emissions which is why
architects and builders are turning to
alternatives.
Practise Architecture built a
sustainable three-bedroom home
in Cambridgeshire with the aim
of addressing the vital issue of the
energy consumed and carbon
produced by buildings. They used
a mixture of hemp and lime called
hempcrete, which is poured into
timber frame cassettes which
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become insulating when dry.
The exterior is covered in corrugated
panels made of fi bres from the outer
coating of the hemp stalks combined
with resin taken from agricultural
waste. This is all produced by Margent
Farm where the home is located.
Hempcrete is a carbon negative
material, meaning more carbon is
removed from the atmosphere by
the growth of the plant through the
development of the thick wooden
stems than produced by it. The
hemp can grow up to 4.5 metres
in four months. It is the stalk that is
chopped up to construct the concrete
alternative.
As well as the low carbon benefi ts,
hemp is naturally pest and weed
resistant, which means there’s no need
for harsh chemicals. It also requires less
energy to heat the homes, meaning a
reduction in energy bills.
Improvements in the building industry
due to the energy effi ciency of plants
and the process of burning new waste
material instead of traditional fossil
fuels have helped reduce the average
CO₂ emissions per tonne of output
by 18%.
But how great is the growth of this
plant-based industry? We meet the
makers that help make hemp into
a home.
The Alternative Architect
Winkens Architecture in Wexford,
Ireland, designed one of the fi rst
hemp houses in 2012. The two-story
residential property is situated in
County Longford. Owner of the
practice, Zeno Winkens, said:
“I was very happy working with
hempcrete in this project. It is very
forgiving in Ireland’s climate unlike
straw bale which I have also worked
with.
“It takes in moisture but can release
it again. A good lime render will help
with this.”
Zeno noted that while demand for
hempcrete is ‘as good as none’ in
Ireland, common Irish household