May-June 2012

ARCHITECTURE
APPLYING PLASTER:
Once all the bag work is complete, the structure shall be
plastered as soon as possible to avoid prolonged exposure to
the sun. Mud plasters are most commonly used on earth-bag
structures, but lime and cement plasters may also be used if you
place a mesh over the bags to hold it in place. A final color coat
can be applied by painting the plaster.
MERITS AND LIMITS:
Earth-bag building technology is as much accepted as it has
been doubted. Despite the structural testing conducted on
earth-bag homes and various prototypes built across the world,
the local building codes do not yet support them making it
difficult for the home owner. Being an unfamiliar alternative
construction method, many banks are not ready to extend
financial assistance to the builder. Still, even if a bank and the
local building officer agree, there might be other difficulties.
To remain structurally sound, these homes are engineered to
be small. Bigger structures can be accomplished by building a
series of interconnected domes, or by extending underground.
One of the oldest uses of earth-bags is in the control of
devastating floods. This fact has been well exploited in various
examples to make small pond structures using earth-bag
building system (bags + barbed wire). But when it comes to
waterproofing the homes in heavy rain locations, the system
seems to lack a foolproof method. Experiments suggest that
covering the structure with cement-rich stucco will do much
work. But in rural areas, the cost will be a major hindrance to this
method. In some shelters, the structures were covered
with plastic sheeting and then plastered with mud. This, if
required, can further be painted with roof sealer to increase the
resistance to water.
Cool in summer and warm in winter, earth-bag homes win over
the contemporary way of construction in the level of comfort and
thermal insulation they provide. Another succeeding factor is the
‘do-it-yourself’ methodology and easy availability of materials
that make this technology very cost effective.
Grain bags and barbed wire are available throughout most
of the world or can be imported for a fraction of cost. Filling
earth can be taken from the site itself or can be brought at the
cost of transportation from a nearby source. Some countries
have advantage of mechanized gravel yard that produce vast
quantities of rejected fine gravels, which can be purchased for
a cheap price. The ease of construction also reduces the skilled
labor required for the work. The cost of the covering plaster is a
critical aspect, where one needs to carefully choose the method
and material of plastering. The plastering method can either
boost or save cost of your shelter.
© CALEARTH INSTITUTE
spacesnepal.com 26
May - June 2012