CREATION OF CHEMICAL BARRIERS TO HUMIDITY

The walls of the old buildings are often subjected to infiltration of humidity from the foundations.The origin of the phenomenon is the porosity of building materials that determines the ability of the material to absorb water and to transport it through capillary rise.The action of water on the masonry involves a whole series of harmful consequences that appear in the form of humidity stains on the walls, efflorescence of water-soluble salts and thus detrimental to the building, friability of the bricks forming the wall, crumbling away of the junction material and plaster, flaking and detachment of parts of the coating of mural painting, development of sponginess in the wall and the wooden parts used for the construction, proliferation of mold and microorganisms.The most effective way to counter the rising humidity is resorting to chemical barriers.The procedure consists essentially in the introduction of suitable protective agents, by injecting through the downwards inclined holes in the masonry, for natural fall or better under pressure.

As material to be injected are indicated:

• liquid cement, for filling large cavities;
• siloxanes, for waterproofing of the pores’ walls against the water rising.

The surface tension is lowered so that the wettability of the wall with water is greatly reduced and the suction by capillary practically entirely prevented.The success of an effective and durable barrier against the water rising per capillarity depends on the depth of penetration, in other words from the impregnation of the masonry by the product of impregnation.