Honeycomb Wall Module: Detailed manual
Bamboo stubs of different Ø dimensoin but with equal height, placed randomly on a board. Even
split
stubs work.
A wall panel 60 x 240 cm, is built flat on a bench. 60 cm is a common width for
a
module to be handled by two people. 240 cm is a common ceiling height, although optional. In a hot,
tropical
climate without AC, a higher ceiling is usually desired. A final module weight of max 50-60 kg is
practical
for the wall assembly without lifting machinery.
Bamboo stubs are cut according to the standard wall
thickness chosen: 7-15 cm? They are almost randomly placed on top of a planar board, like an OSB.
Even
broken stubs can be used if having the same length. The number of stubs needed depends on the density
desired. If placed side by side, the impact resistance becomes extremely high, whereas if reduced by
50%,
the wall could still be strong enough. A practical evaluation of different stub
densities
is worthwhile for project economy.
Later
on centering of the load bearing culm with cones in rig (green).
When positioning the stubs on the board, a 10 cm wide space is left on one of the long side of the
module
for a vertical loadbearing culm to be included later on. 3-4 stubs should line up next to this space
for
later fixing to the culm.
Likewise, 2-3 stubs should line up on the upper and lower sides
of the
module for later fixtures to floor and ceiling.
Rig rink (green), lower side here removed for viewing details.
Protective slats screwed
to
stubs later on.
On top of all the bamboo stubs now placed on the OSB, a fine meshed chicken
net
is stapled, with at least three staples on every stub. A completely flat and stiff galvanized
plaster net
with a mesh 20x20 mm, would be better.
(Although difficult to find in Brazil) The whole cluster of stubs can then be lifted off the OSB,
flipped
upside down and placed on the floor.
The board must now be equipped with "rinks", which are simply lists with a 1 - 2 x
3-6 cm
section, fastened with screws along all the sides of the OSB. The rink, will now form a pool to
contain
the liquid mortar mix. To achieve a smooth final surface of the wall, a plastic film is placed on
the
bottom of the pool also covering the rinks.
Rinks fixed to board.
Ebiobambu, Visconde de Mauá, Brazil Nov 2025
The board must be level for equal thickness of the
exterioir skin.
The plaster mix should now be prepared with the volumetric proportions 1 cement
to
3-4 sand. The sand must be sifted to avoid over-size gravel stones sticking out. If color pigmenting is
planned, it should now be added to the dry cement/sand mix.
A small-scale sample mixed with
water for evaluation is now worthwhile to get the proportions right.
When cement, sand
and
pigments have been thoroughly mixed in a clean bucket, water can now be added, little by little, so as
not
to ruin the plaster mix by too much water. The total volume of the plaster liquid should be calculated
as
60x240x1cm=14,400 cm3=14.4 liters. Only trial and error can determine this parameter. The final
plaster skin could be much thinner than 1 cm, maybe down to 0.6 cm, in which case the total plaster
volume
is adjusted accordingly.
Make sure that the board is perfectly level so that the wet mix is spread with
equal
thickness all over. A vibration device facilitates this: A stick screwed to the plate of a grinding
machine
going back and forth, makes enough vibration of the OSB board and the plaster pool.
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Cross
Section: Fastening load-bearing culm to lined-up stub. Refer to "Centering" perspective, to the
left.
After 1-2 days, when the cement has hardened, the honey-comb wall module can be
lifted and separated from the OSB-board-pool and the plastic film. The load bearing culm can now be fixed to
the 3-4 stubs lined up.
All holes in the culm should be drilled from outside before assembly. The Ø10 mm holes first, then
the
Ø5 mm holes. To find their mirrored positions, a paper can be wrapped around the load bearing culm at the
Ø10
mm hole. The culm circumference is measured and divided by 2 to find the position of the Ø5 mm hole.
Finally,
when the loadbearing culm has been positioned at the center-line of the wall module, the Ø4 mm
holes
are drilled in the receiving 3-4 stubs.
To finalize everything, a 35xØ5 mm screw with a Ø7 mm large head is fixed to a Philips screwdriver with
masking
tape. Then it is entered through the 10 mm and the 5 mm holes to finally drive the screw into the 4 mm hole
in
the stub, here acting as a nut!
Preferably this culm should have been fixed at the center axis of the honeycomb wall module seen from
above
(in plan view).
The bottom end of the honeycomb module should be fortified with 60 cm bamboo
protective slats under both edges of the stubs, drilled and screwed. See detail cross section A2.
Between
those two slats there will be a guide rail, which is also a slat but fixed to the floor. This guide rail
runs along the entire floor edge. This way the honeycomb module will fit snugly to the other adjacent
modules.
Fig:
Honeycomb wall panel cross-section with external ferro-cement skin protecting against rains, UV (
sun),
fire hazards, mosquitos...Optional interior cladding.
The
red guiding rail has to be fixed to the concrete (presumably) floor before mounting the wall
modules.
The upper side of the same module should be fixed to a recomposed beam, 6-8 cm high running on top
of
the entire wall, maybe 4-5 meters long. This fixture could be just a 6 cm screw going through
the
beam and then entering the lined-up stubs. After initial markings by a few turns of the drilling
machine, Ø4
mm bore holes in the stubs may be necessary to avoid splitting by the screws.
This recomposed top beam distributes the weight of the roof structure down to the load bearing culms.
The
red guiding rail slat has to be fixed to the concrete (presumably) floor before mounting the
wall
modules.
From another manual (KnockedDown): Focus_2_Foundation (available on request):
The very
first
bamboo item to install on the construction site is called Guide Rail (red). This slat of approximately
40x10
section has to be nailed, or fixed with expander bolts, to the foundation/ floor with accuracy. It
should
follow the foundation/floor edge in a straight line. See details for precise measures.
First of all, drill holes in the bamboo slat for nails or bolts to avoid cracks.
This Guide Rail will secure that all Honeycomb wall panels land in their right positions.
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