The house made of hemp
America's first house made primarily of hemp has been built.
Using a product known as Hemcrete – a mix of industrial hemp,
lime and water – a team of 40 volunteers, sub-contractors and
designers have recently completed construction of a hemp house
located in Ashville, North Carolina (NC). Eco-friendly design
and construction company Push Design has gained the support of
community members and local officials alike and now plans to
build more.
Using a product known as Hemcrete – a mix of industrial hemp,
lime and water – a team of 40 volunteers, sub-contractors and
designers recently completed construction of the hemp house in
Ashville, North Carolina (NC). Eco-friendly design and
construction company
Push Design
have gained the support of community members and local officials
alike and now plan to build more.
Using hemp as a building material is not new. Hemcrete is a
registered brand of hempcrete, a material has been an
alternative building material used in Europe and Australia since
the 1960's. The use of hemp in buildings dates back millennia in
Asia and the Middle East where the Cannabis plant originates
from. The biggest challenges of using hemp as a building
material in the U.S are regulation, supply and cost, all of
which are related.
David Mosrie of Push Design explains: “The main negative
effect of the legal situation [in the U.S] is the cost to import
it, which is frankly very high. Even while [the government] is
legalizing medical marijuana now in 19 states, [they] can't seem
to allow industrial hemp production. Local production would not
only lower the environmental impact exponentially versus
bringing it from Europe, but would bolster a struggling economic
group and prop up local farming, a long regional tradition. It
frankly makes no sense to keep up the ban , at the state or
federal level, but it continues on.”
Given the restrictions on hemp production in the U.S, Push
Design sourced their industrial hemp from the U.K through the
company Tradical via a fellow NC company Hemp Technology.
“We are very lucky to have Hemp Tech and their founder, Greg
Flavell, here in Asheville,” Mosrie told Gizmag. “Greg is one of
the top experts on hemp in the world. We have been looking for
the most effective, sustainable and energy efficient toxin-free
building material for years, an effort that we still put time
into every single week. We recognized almost immediately that
hemp was, in every way but in cost, seemingly the most effective
and sustainable material available worldwide. The qualities it
offers are beyond anything we get from typical materials,
combining energy efficiency found in mass-based construction
with the carbon sequestration, rapid renewability, strength,
several hundred year wall lifespan, and the breathability and
indoor air quality that is unsurpassed. It is an incredible
combination, and a list of positive attributes we have never
seen in any other material.”
Hempcrete has some interesting qualities one of which is it's
ability to pull carbon from the atmosphere both while being
grown and while in-situ producing a double edged sword for
fighting climate change. Firstly at the cropping stage the hemp
plants naturally use carbon dioxide for growth at about 22
tonnes per hectare, however the interesting factor is that the
building itself continues to sequestrates carbon as lime in the
hempcrete calcifies over time.
“The fact that the lime content is constantly calcifying,
turning to stone essentially, over the wall’s life span, means
the wall is actually getting harder and stronger as time goes
on,” Mosrie said. “The durability is unlike anything we have
seen, with the exception of stone, as perhaps even beyond that
as there is no mortar joint failure possible. Studies in Europe
have estimated about a 600-800 year life span for the wall
system.”
The interior of the house is lined with recycled paper panels
known as PurePanels. This material is 100 percent post-consumer
recycled paper which is corrugated, and panelized. It is lined
with Magnum Board, a breathable, natural sheetrock replacement,
using organic glue. The panels are lap jointed and installed at
about five panels per hour using a glue strip and four screws
toenailed into the floor and ceiling. “The result is a
sustainable, toxin-free, breathable panelized wall system that
goes in very quick and is counter-intuitively strong,” said
Mosrie.
The doors are made of the same material skinned with hardwood
veneers, are fire rated and incredibly light. Window frames in
the house were recycled from demolished houses with the heavier
and better insulating glass replacing the old panes.
In all it took the team nine months to build the house,
however Mosrie believes that future projects would take around
half that time. The longer construction time was due to
unfavourable weather conditions and the teams' inexperience in
using hempcrete.
Push Design have recently signed contracts on several new
homes in the Asheville area, and on two micro-developments of
five units each, also in Asheville. Push is also acting as a
consultant on supplying materials to dozens of projects destined
to use Hemcrete from Texas to Colorado to the East Coast.
And if you want a house built using hemp and are worried
about people trying to smoke it, Mosrie puts it this way: “We
tell folks they would have to smoke the master bedroom to get
high! It would take smoking 2500 lbs of the hemp to get high, so
it is a losing effort.”
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