Mold inside a 3-year-old house wall/ceiling corner

There is already the possibility of a construction defect.

If the shell builder did not properly install the Styrodur insulation at the edges of the ceilings in the corner.

Our energy consultant was really on top of that. For example, we had a small defect in one corner, where the shell builder did not install Styrodur between the attic structure of the garage and the house. We were lucky because our bathtub is located exactly in that corner, so we applied thermal insulation from the inside there.

There is indeed the possibility of a construction error. If the shell builder did not properly install the Styrodur insulation at the ceiling edges in the corner. Our energy consultant was really on it.

Many construction errors can actually occur. I am seeing it now in our shell construction as well. We have a Poroton-drs neo ceiling edge shell at the ceiling. They are actually good but they do not always lie completely flat. Additionally, the bedding layer for the Poroton blocks is also a potential thermal bridge.