Good news. The leak that has been plaguing my home has been plugged. After the roofer performed his fix the water has stopped running down my walls as soon as it would rain.
The repair wasn’t too expensive either. For just under 100 euro things were patched up. Now to fill out the paperwork for the insurance and hope they reimburse me. After that, the only thing left to do is reapply the wallpaper. That won’t happen for a while though, since the walls need to dry first.
At least no more weeping walls.