ᐅ Condensation Moisture / Dew Water in a House Ready for Interior Finishing

Dear community,

Since I only have limited knowledge about this subject, I am reaching out to you. We have purchased a house finished up to the stage ready for interior work (basement, ground floor, upper floor, attic). During the last inspection to get a quote for a turnkey package, we noticed a damp wall in the attic corner (drywall, shaft). Additionally, there was dampness under a windowsill on the ground floor.

We immediately contacted the builder, who arrived within 2 hours and assured us that this issue was already known. A roofer ruled out any roof damage. The builder said it is condensation. According to him, all walls and related areas will be checked and replaced if necessary.

Naturally, we are now concerned about the house and would like to ask for your opinion.

Based on these pictures, it is "very difficult" to provide a well-founded assessment, if not impossible. You should consult an independent expert; hidden water damage, no matter the source, can be quite severe. I wouldn’t trust the builder right away 😳
Of course, I’m not saying he is necessarily wrong! But if things turn out badly, he might be dishonest, the damage could be extensive, and you will have to deal with the consequences later on...

On Monday, we will give them a call and hire an expert. Does something like this basically happen? Is it common for such situations to occur? Or is this truly an exceptional case?

DPelin1 schrieb:

The developer said this is condensation. According to the developer, all walls, etc., will be inspected and replaced if necessary.

Did he really say that? So he is willing to replace walls if needed? I’m not so sure about that 😎

Condensation in an unoccupied (and therefore unventilated) house wouldn’t be unusual by itself. But like many others, you’ve just uploaded close-up pictures without showing the bigger picture. Maybe the context (surroundings) could help determine whether the areas affected by condensation might be potential thermal bridges or not. That’s why: more photos of the overall situation. More information about the circumstances (history), and then maybe a more detailed and qualified answer 😉

Is the first picture taken at the ceiling? I find that the stain has a strange shape for condensation water.

If it is a service shaft, there will also be pipes running through it, which may exit on the roof, for example, exhaust vents, bathroom ventilation, or gas pipes. If the shaft is not properly sealed where it meets the roof, water can sometimes leak down inside. For example, a chimney may have a lead-zinc flashing; if this is not properly sealed, water will run down the chimney or masonry. So, I would go under the roof and inspect what is happening above the ceiling where it is damp.