If your walls are turning black in a corner, it’s no accident: find out what it really means (and how to fix it)

And sometimes, it’s the insulation that works against you. A “thermal bridge”—a place where the temperature varies greatly between indoors and outdoors—can create a cold spot where moisture can easily accumulate.

A small detail that we don’t always think about: furniture placed too close to the wall. Without space for air to circulate, humidity stagnates and mold discreetly settles behind the sofa or dresser.

According to the ANAH (National Agency for Housing and Housing), one in five homes in France shows signs of persistent damp. Suffice it to say, you’re far from alone in this situation.

A golden tip: don’t underestimate these hidden corners. They’re often the first to « speak » when something isn’t right.

How can I react immediately to prevent it from getting worse?