ᐅ Windows Are Leaking and Mold Is Forming – Window Sill Is Cracking

Hello everyone,
since the completion of our house (built by a developer) 4 years ago, we have been experiencing problems with the windows on the east side.
Water runs inside onto the window sill, causing damage. The interior sides of the windows are developing mold.
We have already reported this to the developer several times, but they place the responsibility on us to ventilate twice a day to prevent these problems. Our warranty expires next year, and we want to have this issue resolved once and for all.
Is it worth having an expert come to assess the situation and insist on a replacement or readjustment of the windows, or is there nothing that can be done and we just have to accept the ventilation requirements?

I would really appreciate your opinions.

Hello,

I would suspect both condensation and water coming in from outside.

There is a drip edge at the bottom of the window (last picture), which allows water entering from outside to drip off and exit through the intended openings (6th and 7th picture). There is no fault at this point.

The problematic issue is the gap in the outer seal, especially at the bottom. Here, drip water can penetrate into the interior of the window. Cold air also enters and causes condensation.

Equally problematic is the clip of the interior roller blind or pleated blind. Because of this clip, the sealing gasket clearly no longer fits tightly against the window frame. The moist, warm air from the bathroom is pushed outward (positive pressure), condenses, and causes standing water.

Honestly, the windows don’t look well maintained, so I think you bear some responsibility for the condition. In the fourth picture, the window is heavily fogged up—that needs to be ventilated. You might want to focus on this gap in the outer seal and use that point when discussing the issue.

Best regards