1. Removal of contaminated plaster up to the highest
point reached by rising damp.
2. Accurate cleaning of masonry, also considering
washing using a pressure washer.
3. Cladding, where needed, of masonry surfaces
using materials that are compatible with the specific
composition of the wall.
4. Application of a first layer of salt resistant pozzolan
plaster, 1 cm of thickness, fully covering the wall surface
(up to the floor). The salt neutraliser must be mortar
made of natural hydraulic lime, pozzolan hydraulic
binders, marble dust, silica sand, natural air entraining
agents. This compound, which must guarantee secure
grip to the surfaces to be treated, will create a barrier
for the salts inside the masonry (sulphates, chlorides,
nitrates). Proper use of a salt resistant plaster with
these features will not need preliminary sulphate and
nitrate fighting treatments.
5. Application of a lime-based renovating plaster (in case
of humid masonry) or a lime-based plaster (on a dry or
semi-dry wall). It is good to avoid contact between the
new plaster with the floor (therefore it should be placed
some centimetres above) to prevent any absorption.
6. Application of a lime finish.
7. Painting using limewash or silicate paint for internal
walls.
8. Protective coating with silicate or siloxane paint for
external walls.
9. Application of baseboard, if any, using silicone or
proper glue: do not use metal nails (they are not
compatible with masonry materials for rehabilitation
purposes).
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For finishes or absorbing paints, in case of water-
exposed facades, it is appropriate to treat the surface with
nanotechnology-based, fully-breathable, transparent and
non “film-forming” protective coatings.
REPLACEMENT OF CONTAMINATED PLASTERS
ALTERNATIVE TO PLASTER REPLACEMENT
Once a certain degree of dehumidification has been
achieved, if salt-contaminated plaster cannot be replaced,
you can reduce hygroscopic moisture through poultices of
specific “salt-absorbing paste”, which remove significant
amounts of salts from the walls.
By applying this cellulose paste soaked with distilled water
on the damaged wall, salts melt (up to 3-4 cm inside the
wall) and, as water evaporates, they are absorbed by the
paste.
After evaporation is completed, the dried up cellulose will be
removed using a spatula, along with the salts. Repeat this
operation at least twice.
This solution does not ensure removal of all the salts but
still gives good results, not to mention it is the only possible
solution if plaster cannot be removed. It is important to
stress that the support must be highly breathable, otherwise
the “anti-salt” method cannot work properly.
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