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Rendering the substrate with a parge coat.
There
are
two
common
possibilities
for
installation:
either
directly
on
concrete elements
or
on a
parge
coat
covering a brick wall. If installation is to be performed directly on pre-fab concrete or concrete poured on-site, it
will be necessary to wait several months to ensure that the cement has cured fully. As a general rule, the waiting
time is 6 months. If the coverings will be installed on a parge coat, then the waiting time will be one week for
each centimetre
of
thickness of the
parging,
so as to
ensure that
the better
part of
the movements
caused
by
contractions have been completed.
For the preparation of the parging, it is
recommended to use
unicem
, a synthetic resin-based latex that, when added
to the water in the mix, reduces the water absorption of the mortar and enhances its cohesion and deformability.
Essential characteristics of the parge coat: it should be perfectly
flat
, with deviations of less than 2 mm, checked
using a 2-m. straightedge. It should have a
course texture
to ensure good mechanical adhesion of the adhesive.
The substrate must be
firm and solid
, with any damaged or crumbly parts being repaired or removed; it
should
be free
of
dirt and
residues.
For
applications directly on concrete,
special care must
be taken
to
remove any
traces of hardened cement slurries or form-stripping agents; the substrate should have a proper degree of
water
absorption
, since a highly absorbent substrate may cause the adhesive to dry out quickly, leading to faulty setting.
It is absolutely necessary that it is not water-soaked, frozen or at a high temperature.
