Who hasn't had humidity problems ??
In the photos it reminds me of memories !!
I don't understand Spanish, except guessing, but
clearly, it is a promotional site to sell devices and wall treatments against humidity, SPAM type, Spanish !!!
The humidity leads to colds, allergies and illnesses, especially in children, so dry your walls with our SPI electrical devices !!
http://www.innovaidea.es./AHE%20Elimina%20Humedad.pdf
I will finally understand Spanish !!.
So SPAM, hidden for advertising a wall ventilation device with electric electromigration !!
Humidity is complex, with all the basic physical phenomena and even living microorganisms:
Condensation, evaporation, solidification (in ice, dislocates, breaks everything), dissolution of salts in the walls which migrate with water (like white calcite, contained in any cement) and are deposited in white or dirty powder where this water s evaporates in a windy and warmer place !!
Thus this slow but continuous transport of the cement salts from the interior of the wall to the surface has a destructive effect, on plaster and porous walls. The salt is deposited and to have room pushes the paint or the surface of the wall which prevents it from growing when the water deposits it by evaporating.
Thick cements, compact as concretes, in principle do not let water pass and are therefore only affected on the surface (otherwise the concrete bridges in the rain would be quickly damaged)!
Calcite is different from saltpeter, although they can be confused quickly, but
old gunpowder manufacturers, do not confuse them, because with calcite, the powder never fires. !!
Calcite is calcium carbonate which transported with water in the caves gives stalactite and stalagmite concretions, which form very quickly as soon as the water passes through a cement slab !!
I experienced it 15 years ago when my neighbor upstairs started to water his plants too much more than the rain and the water through the slab ended up in my balcony, transforming it into a cave with beautiful concretions !!!
It was very difficult to solve the problem, and the condominium at our expense, had to make its only balcony perfectly waterproof, like a swimming pool, simply because of its obsession to water constantly!
Your photos are calcite, not saltpetre, coming out thanks to your devices which accelerate the migration of water to dry the walls !!
http://fr.wikipedia.org/wiki/Calcite.
Also, I know how to distinguish calcite from saltpetre, formed of potassium nitrate, which do not require the same conditions, it requires a closed environment, sheltered without light !! !!
http://fr.wikipedia.org/wiki/Salp%C3%AAtre
Saltpeter comes in the form of white fibers with the appearance of white hairs. In old humid cellars or houses, saltpeter is one of the residues of development of bacteria that feed on ammonia from soil water and potassium carbonate in the walls. The transformation ends in contact with the oxygen in the air to form potassium nitrate or "saltpetre". We often see these white fibers in old buildings that have housed animals or near an old septic tank, ammonia forming there from the urine. The mineral salts are in solid white form. Saltpeter and mineral salts are present throughout the thickness of old damp walls and concentrated on the surface of materials. This saltpetre was formerly harvested in cellars or certain caves for powder.
Finally, in case of humidity, before using this type of device, it is better to stop at the source, draining around, making the wall or the floor waterproof and only as a last resort your system, good for old castles that cannot be rebuilt or modified !!
and to respond to my friendship with Pascal H, a souvenir of the Mondial in Paris.
A+
Photo suite has a water leak that has been in the wall for several years.
