Building with earth - Gernot MINKE (1)

13 Repair of loam components
Damage in loam components can occur
due to shrinkage by thermal contraction and
expansion, through water impact or by
mechanical impact and abrasion.
If a plaster contracts when drying, or does
not bond sufficiently with the ground surface,
it may separate from it. Such weak
areas can be easily located by knocking the
plaster with the knuckles. If large quantity of
water condenses in the wall and cannot be
removed quickly enough, the loam might
swell and cause the plaster to crumble and
fall off. Such damage can also occur when
water seeps through from the outside
through cracks or holes.
Frost can also cause a similar damage if
the wall is moist and the freezing water
expands.
Repair of cracks and joints with loam
fillers
Repair of damaged sections of loam, especially
cracks and larger joints, demands special
measures differing from those used for
conventional masonry or lime plasters. This
chapter describes loam-specific repair problems
and retrofitted thermal insulation
methods using lightweight loam.
The occurrence of damage in loam
components
13.1
Joints and cracks in dry loam components
cannot be repaired with plastic loam as this
does not bond with the dry loam surface.
When drying, the filler will separate out and
can fall off. Therefore, it is important to pretreat
the joint and use a mixture having as
little shrinkage as possible.
Mixtures
While designing the composition of the
loam filler for cracks and joints, the following
should be considered:
• The filler must have sufficient binding
force to stick to the moistened surfaces of
the crack or joint.
• The mix should contain sufficient coarse
sand or other coarse particles so as to
minimise the shrinkage. Fibres or hair may
also be added for the same reason.
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Repair of loam components