Graffiti e Cementi, La Peruviana, Seveso, Milano



Graffiti

The main cause of the deterioration of the graffiti is damp and the effects caused by thermal shocks, which cause the various layers of plaster to swell, resulting in progressive flaking away. After the cleaning stages, done with water sprayed at low pressure and poultices, operations of consolidation and re-adhesion of the layers that were coming away were carried out, and for the missing parts we opted for reconstruction with a traditional technique: application of two layers of plaster. To give back unity to the whole building the same design was followed, always based on the original.

Cementi

On the facades, all the elements made in decorative cement, protected in part by the gutter cornice, were in a fair state of preservation, while as for the balustrade of the main stairway and the parapets of the terraces, the parts more exposed to the weather, the deterioration had gone so far as to make the material crumble away, and in some points had led to the total loss of parts of the building. The cause of this grave deterioration of the cement is the phenomenon of carbonation. The high degree of porosity of the material due to the aggressive action of the weather allows the water to penetrate inside the cement elements as far as the metal reinforcing rods and rust them through. Deterioration here can lead to quite large fissures or cracks, and in more serious cases the concrete covers have come away completely with a total loss of parts of the material. To date, the cement has been restored to all the elements of the facade in a fair state of preservation, so with pathologies regarding above all consistent surface deposit in dust, biological patina and black crusts. Before the biocide cleaning treatment was administered various tests were carried out to find the best cleaning technique that would not alter the nature of the material. Depending on the consistency of the deposit, various cleaning systems were employed: water spray, poultices soaked in de-mineralized water to extract soluble salts, and ammonium carbonate poultices for cases in which the deposit was thicker. Grouting was done with cement that was compatible with the original, and preventive treatment was carried out to stop biological agents re-forming, and water-repellent protective treatment was used on all the cement surfaces.