1) Greenhouse plastique+ mobile-home
a) Realization
A greenhouse of 8x15 m (galvanized iron arches, wire of iron
of frame, breaks into leaf of transparent polyethylene) under
which is engaged with half mobile- ahome of 25 m2
The polyethylene sheet is bleached of a good layer of white of
shade before each estival period. A fabric veil (cotton cloths
of recovery) is slipped between iron wire and the plastic, it
reinforces the shade and absorbs the moisture which condenses
on the interior face of the plastic the fresh nights. This moisture
dries during the day.
The pinions of the greenhouse are closed with summary walls in
bundles of straw. Coarse frames out of wooden are used as casing
with two doors isoplanes of recovery, one on each pinion of the
greenhouse . These frames are independent of the structure of
the greenhouse which is flexible and must be authorized to become
deformed with the wind. This elastic strain can determine a play
de10 cm of the arches around their position at rest.
On the ground, bricks punts of terra cotta are posed dry on a
sand bed, and make a dismountable tiling in the part "dining
room". Elsewhere, with the recovered lino the ground covers.
Housing is connected to the electrical supply network (professional
meter) and to the network of water conveyance, but not to the
whole with the sewer, the network not extending to the ground.
b) Equipment
- a summary electric installation (lighting, catches).
- a bathroom (wash-hand basin, bath-tub).
- a washing machine.
- a sink of kitchen, gone up dry on breeze blocks.
- a gazinière with propane
- a small electric convector of 1000 W, to heat the mobile-home
a little when the weather is cold.
The small water-heater with propane has cold
with the cold first, the family was satisfied with water heated
on gas.
Gray water was evacuated towards a 5 m length open trench on
30 cm of depth, outside the greenhouse, with the downstream.
A toilet with litter was installed in a tiny room summarily arranged
in a corner of the greenhouse. The waste of the toilets was drained
with measure to an unoccupied corner of the ground.
The mobile-home was used as dormitory for the three children
(4, 11 and 12 years), and spaces it of 120 m2 available under
the greenhouse was partitioned with fabrics suspended on the
reinforcements of the greenhouse, so as to allow a minimum of
visual intimacy for each one
c) Use
The level of comfort of such a housing is limited obviously enough.
The thermal variations are very important, one reaches 30 with
35°C the day in summer, and -5°C in the early morning
the winter. All the pipes of plumbing are out of polyethylene,
and do not fear freezing. It is imperatively necessary however
to close the valve of arrival and to open all the taps each time
freezing threatens. The mobile-home appears about also hot and
as cold as the greenhouse. Essential: a good feather bed for
each one.
Minor defects: there is movement of air in abundance inside as
soon as the wind rises, and the acoustic intimacy is about null.
In spite of these disadvantages, this habitat appears very pleasant
in mid-season, partly because of the soft light which filters
by all the surface of the ceiling and the walls, and also of
the immediate perception of external environment: the rain, the
noise of the wind in the trees, the song of the birds. With the
legitimate occupants, one crosses a crowd of squatteurs there
finally sympathetic nerves: hedgehog, mante religious, snails,
clamping plates, wasps build, mislaid birds, etc.
d) Risks
The principal risk specific to this type of habitat is undoubtedly
the storm, which can tear off the plastic, to even crush the
metal structure. Measurements of prevention are simple: as much
as possible, to settle with the shelter of the wind, to lay out
the axis of the greenhouse perpendicularly with the dominant
winds, to choose a well braced structure, to look after the assembly,
in particular the tension of iron wire of frame, to pose the
plastic correctly and to bury it well in trenches some 40 cm
depth at least dug 50 away cm from the base of the structure,
all well-known rules of the market-gardeners.
In the event of opinion of storm, to evacuate housing.
For the remainder, it is rather easy to secure surface waters,
and if the iron wire and the plastic are well posed, there will
be no gutters, even if a cat perforates the cover with its claws.
2) Studio framework wood+staw under a plastic greenhouse
a) Realization
Under a greenhouse of 9x8 m, one poses a floor of batten (7x6
m) on a batch of homogeneous pallets spread out over a plastic
sheet. On this floor a flight ramework of wood is assembled around
fifty of vertical posts (210x6x6 cm), a large central post, two
beams and a score of beams (12x4 cm). The posts are distributed
on two perimeters, one at the edge of the floor, the other fifty
cm in withdrawal, towards the interior. Between these two rows
of posts, one piles up the bales of straw by leaving a door and
two windows (joineries of recovery).
The beams carry a ceiling of batten on which are laid out two
or three layers of paperboard and over bundles of straw.
Deduced once the surface occupied by the walls, it remains approximately
30 m2 livable inside the walls, plus 2 "corridors"
of 1,50 m width between the shhetof the greenhouse and the walls.
The walls of straw are coated with ground on the two faces, the
interior coating is very thick (approximately 6 cm), which gets
a little thermal inertia to housing.
The axis of the greenhouse is directed North-South. The southern
pinion carries two large windows, whereas in north, the very
whole greenhouse is closed of a summarily high additional wall
in bundles of straw.
Housing is connected to the electrical supply network (professional
meter). It is provided out of water by an electric pump assembled
on a well in the vicinity, the water of drink and kitchen being
bought in bottles. It is not connected to the whole with the
sewer.
b) Equipment
-electric Lighting, catches.
-a shower sink and tub, with a small drain covered for gray water.
-cooking with propane
- a wood stove
- a toilet with litter
c) Use
The floor and the ceiling were carried out with still wet batten.
While drying, it left open joints so that the ventilation of
the part is important. As in addition thermal inertia is rather
weak, it is necessary to heat regularly in winter.
In summer, the greenhouse passed to the white of shade and the
southern frontage is protected by a pergola, which is enough
to ensure a temperature lower than 25°C in the studio.
In cold period, the abundant condensation which occurs the night
under the plastic sheet falls down in rain on the straw of the
ceiling, which it ends up wetting in-depth. It is advisable to
envisage a means of absorbing or of evacuating this moisture:
veil fabrics posed under the plastic, or other.
d) Risks
In addition to the storm, it is necessary to prevent the fire
hazard here. The walls in straw coated well are non flammable.
It is necessary to lay out the stove on a fireproof mineral plate,
and to look after the exit of the flue.
In this housing as in the precedent, the feeling to make the
provisional one should not bring to neglect safety. For the electric
installation, one will neglect readily the standards which impose
useless equipment (taken in 32 amps on a clean circuit for an
electric furnace, for example), but certainly not those which
milked with safety.
3) Discussion
The principal interest of these residences is due to their very
low cost, the speed and the simplicity of their construction.
The tiny investment authorized at the beginning is about completely
recoverable at the end of their use, by re-use or resale of the
elements.
In the first model, the mobile-home can be replaced by a caravan,
less expensive and much easier to transport. This type of habitat
is to be held for the soft climates, and to install if possible
in shaded site. Its use can be only very temporary, although
one meets in edge of sea of people who live at the year in mobile-home,
and whom the gipsies pass all their life in the caravan.
The second (studio straw under plastic greenhouse) is moderated
much better, one can make heat, it can put up himself with the
hardest climates. The floor wood is not essential, a ground of
beaten ground possibly stabilized with lime, or a pavement of
terra cotta posed dry would have the merit to confer a welcome
thermal inertia in winter as much as in summer. As described
above, this housing comprises only one part, but nothing prevents
from associating to him an additional length of greenhouse used
as in the first model, the built part being used as refuge in
the event of excess of heat or cold, and protection against freezing
for the hydraulic equipment (sink, shower).
In horticultural use, the polyethylene covers treated anti-UV
lose their optical properties with the wire of time and must
be replaced the every 4 to 5 years, but their mechanical resistance
is maintained much longer, undoubtedly more than ten years.
In the event of not-connection with the drinkable water supply
network, one can resort temporarily to mineral water out of bottle,
which makes quantity of people connected but dissatisfied of
the quality of the water of the network, or with water of well
or suitably filtered rain.
The management of the human excrements by the means of toilets
with compost (toilets with litter or toilets with composting
interns) is an at the same time simple, sure thing and very good
market, and it is also the case of the gray water treatment (relatively
not very abundant in this type of habitat), by bed of infiltration
or planted filter.
Except particular case, the concern of preserving the landscape
is not an obstacle with the installation of horticultural greenhouses
with an aim of production, it does not have there reason that
this argument is opposed to us when it is a question of placing
people on the place of their work, the more so as these low buildings
are rather easy to blur with bundles of straw or climbing plants.
Pierre Besse 06/01/05
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