Myth?! "Breathing Walls" What is the truth?

If you take the term breathing as a metaphor

Metaphors cause confusion and are therefore perhaps rather counterproductive for a complex topic like house construction...

"The eyes of the house are the windows and its heart is the heating...."

just my two cents

Metaphors and images are fundamentally excellent tools for illuminating complex relationships. They fail when they do not highlight something essential clearly. They fail when they are expected to depict the entire context. They fail when the recipient lacks the will to understand the sender. I also do not find the image "atmende Wände" particularly successful.

What breathes most in the house is the controlled residential ventilation. In a broad sense, one might also include gypsum/clay plaster, as there is still some interaction with the indoor air. However, the wall is largely dead.

The wall certainly has more properties for high living comfort – olfactory, acoustic, optical... Material is simply not the same as material. The controlled residential ventilation is (attention metaphor) a kind of "iron lung" for the house. "Breathing" actually fits better there.

Breathing is associated with air, here it is more about water vapor. But that is also present in the air. Therefore, breathing walls are acceptable. Unfortunately, the discussion often goes in the wrong direction.

I don't think the picture "breathing walls" is particularly successful either.

As long as they don't pant, wheeze, groan, or cough ...