Schedule C.1.2

Typology of the intervention C Preparation of the masonries   
C.1 Defence salty migrations
C.1.2 Temporary plaster   
Purpose of the work

The masonry shows the plaster very deteriorated or absent, marked, in one or more parts; deterioration due:

  • to the located loss of plants;   
  • to the rising damp;   
  • to the absence of a suitable protection to the summit of the masonries.

Under these conditions the masonry has been shown saturated of soluble salts. It needs, before providing to any intervention, to extract soluble salts.  

Formality of the intervention  

Before effecting the laying of the temporary plasters is necessary to perform:   

  • interventions on structures;
  • generic work of preparation of the masonry for the following laying of plasters;
  • the accurate cleaning of the masonry with water and sorghum brushes.   

In the so prepared masonry is spread a layer of   plaster, with limited thickness, manufacturing a generic mortar.  
After an enough period to allow the setting of the mortar (varying in relation to the environmental conditions) the temporary plaster is eliminated and, only in the parts that are more polluted, the treatment is repeated.  
In the zones where the phenomenon of the salty migration had to occurred again, it should better act to a further extraction through "clay packs" (C.1.3).  

Specifications on the materials The temporariness of the intervention doesn't require a detail care in the preparation of the plaster, that can be constituted by a layer, of limited thickness, obtainable with a ordinary lime mortar. The medium/coarse- grained aggregates, deprived of dusts, of salts and of other polluting substances, must be clean.  
Warning Between the mortar and the wall (made damp from the cleaning and from the ordinary mortar on this applied) an osmotic phenomenon occurs; in presence of two different salty concentration solutions (the wall and the mortar) the transfer of salts is activated in direction of the small concentration solution (the temporary   plaster). In the extreme case of a ordinary mortar (because of a polluted aggregate) with a salty concentration greater than that present in the masonry, stretching the plaster, exists the risk to introduce salts rather than to extract them.  

Summarizing files for a critical reflection on the effects of the workmanships

C.1.2 - elements of judgment

Effects

Description

action

salts' extraction  

control of action

impossible

  check of action

possible

time of intervention

long

collateral effects

absent

Elements of analysis

Description

maintenance of informative content

not remarkable  

potential reversibility

reversible

compatibility with the support

good

easy application

good

possibility of maintenance

non remarkable

duration of the effects

immediate effect  

cost

low

 

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