Restoration / Humidity
Every Maltese homeowner knows the sign: The paint bubbles at the bottom of the wall, turns to white powder, and flakes off. You scrape it, paint it again, and 3 months later, it's back.
Maltese Globigerina Limestone is a sponge. It sucks groundwater up from the soil (Capillary Action). This water carries dissolved salts. When the water evaporates, the salt crystallizes and expands, blowing the paint off the wall.
To fix this from the inside, you need a material that allows the wall to "breathe" while blocking the liquid water.