It was really five or six years ago, a couple of things happened: I turned sixty,
and a little granddaughter came along.
My first grandchild, and I really thought about the
future, and her future.
My name is Steve Barron and I’ve built a house out of hemp that we grew in our farm a few years ago.
It was something that I was inspired to do for the planet,
for my grandchildren, to say; let’s help try and fix it.
The construction and building sector is responsible
for 30 - 40% of global carbon emissions,
as well as energy use, as well as solid waste that it generates.
And therefore natural building materials have a big role to play
in cleaning up the building and construction sector for a
sustainable future.
So a hectare of hemp can sequester somewhere between two or three times more carbon dioxide
than a typical forest.
So this stem is about two metres tall and you can see
that the thickness of the stem is about a centimetre and a half
or two centimetres.
Hemp can grow to three or four metres in height and thickness of three to four centimetres in
diameter, and that is what makes it a really good plant material to sequester carbon,
because the carbon is being stored in the stalk, the stem of the plant,
and the oxygen is being released for our benefit, and we can then use the fibrous shive material
for building materials in which the buildings are actually going to be carbon sinks.
So I met Steve and we started talking about some
of his ideas for the project, and this idea of creating a
productive landscape where hemp was grown but also processed.
We wanted to demonstrate that it was possible to make a house that
is effectively carbon negative, and we managed to do that by the fact that the
materials that we used sequester carbon, so they draw carbon out of the atmosphere.
They lock it in, they hold it in the fabric
of the building. So whilst the building costs some carbon to build, that’s offset
by the carbon that is sequestered in the materials in the fabric of the building.
What got me interested in it was that hemp is a plant, it’s like wheat, but
did you know that you can also solidify it and turn it into a hard
bioplastic or a construction material?
I certainly didn’t, and when I found that out I thought
‘wow’, you can bring this wonder-plant and
make it into something.
To use hemp as a building material, we need to
extract shives and fibres from the stalk of the hemp plant.
The shives are the woody, basty material
that can be put together with lime and water to produce something known as hempcrete.
Alongside this, you can use the fibres to produce felt-like
materials and if you impregnate these with bio-based resins.
You can produce these compression moulded panels that can be used for cladding materials,
or for rain screens or roofing tiles.
In making the house, we’ve developed a system that is almost entirely hemp-based.
So there is hemp in the structural panels that make the frame of the building, but also
in the cladding. The house was designed to be made in a factory.
The whole thing went together incredibly quickly, so in two days we had essentially
the frame of the house, the insulation of the house and a roof frame on.
The hempcrete can store heat and energy, so in the winter what that
means is that it drastically reduces your need for additional heating because you
are able to store a lot of that heat energy both from the sun and people using the building.
And in the summer, you get the opposite effect where it helps
regulate temperatures and keep things cool.
We think that a transition to bio-based construction would
have an incredible impact in terms of responding to the climate crisis that we find ourselves in.
What natural material is and bio-based construction offers is a complete
alternative and a way of constructing that can be regenerative, that can have a positive impact.