Location:
Violet
Town, Victoria
Type of Build:
Single
story detached residence
Owner:
Neil
and Sandy Garrett
Designer:
Neil
Garrett
Builder:
Neil
Garrett (Owner Builder)
Size:
24
squares (223m2)
Cost:
Est
$200,000
Date of
construction:
Commenced
2013 est. completion 2015
Purpose of Build:
2/3
bedroom residential home
Choice of Material:
Neil and
Sandy had read about hemp building and first saw a sample at the Hemp Embassy
in Nimbin. They had stayed at “Bramare” a rammed earth house in Bendigo run by
the Otis Foundation for people recovering from breast cancer. They loved the
feel of the house and the colour. They investigated rammed earth, but it looked
like a lot of work for owner builders. Hemp used a similar technique of
creating a monolithic wall using a system of shuttering and had the added
benefit of being insulative. Neil and Sandy have used natural materials
throughout the build, choosing to build with plantation timber, avoiding
rainforest timber or hardwood. They have also reused materials and used pre
owned or reject materials, giving them a new life.
 |
| Oxides used to colour different mixes |
Climate:
Zone
7 - Cool Temperate
Local Council:
Strathbogie
Council but did not use
Obtaining Approval:
The
building permit was obtained on the basis that the Hempcrete product was
certified to conform with the requirements of the BCA. The private building
surveyor assessed the structural plans as suitable, then the hemp was passed as
it was just infill. The house needed to meet 6 energy stars and did so with
250mm hemp walls, giving a R rating of 3.5 to 4.
Construction:
All
work carried out by Neil and Sandy Garrett, except for plumbing and electrical.
To build Neil used St Astier (French) binder supplied by Hempcrete Australia.
He has been experimenting in recent constructions with binder recipes making it
from local materials with good results.
Footings:
Concrete
slab on ground, to the north. Slab is
100mm thick with edge beam and has 50mm expanded polystyrene slab edge
insulation. To the south timber bearers and joists, with silver streak
insulation under joists, brick perimeter wall on concrete strip footing. No
termite barrier as T2 termite treated timber used for frame, subfloor and roof.
Floor:
It
was intended to polish the concrete slab to the north but have decided on a
floating bamboo floor for comfort levels. Timber floor with silver streak
insulation under joists to the south.
Walls:
250mm hemp
walls, using St Astier (French) binder supplied by Hempcrete Australia, cast around 90mm by 45mm F5 T2 pine frame at 600
centres. Render; sand, lime and blast furnace slag.
 |
| Beautiful curved corners |
Windows:
Commercial double glazed aluminium windows and sliding doors.
Ceiling:
Painted
3mm Magnesium Oxide board, with R 3.5 fibreglass insulation between rafters,
with 50mm air gap to the 50mm blanket above.
Roof:
Zincalume with R1.5 foil backed blanket
insulation/sarking over battens.
4.2Kwh solar photovoltaic system on shed roof.
Heating:
Freestanding
European high efficiency slow combustion stove wood heater, with soapstone
surround as heat bank.
Cooling:
Fans,
natural ventilation and a reverse cycle air conditioning to be installed if
required.
Wall construction:
Neil and
Sandy made the walls themselves, using their own 120L mortar mixer. Neil attended
a workshop with Hempcrete Australia and became a licensed installer. Neil periodically
holds hemp building workshops.
Formwork:
18mm form
ply, strengthened with 35 x 75mm pine battens. Formwork attached to frame with
bugle batten screws.
Section Diagram:
Section Diagram:
Technical issues:
Do not render too soon! Allow the walls to
fully dry out before rendering, to avoid cracks in the render. If building
again Neil would not use as much Magnesium Oxide board, he would only use it in
the wet areas but not other walls
Advice/Recommendations:
Talk
to other hemp builders. You can do the work yourself; building with hemp is
very satisfying, low skill and forgiving.
Contact:
Phone 03
57981522
Neil is
Secretary of the Industrial Hemp Association of Victoria
He is
happy to talk to and assist intending hemp builders
