The search is your friend
Well, the search function here is rather mediocre, and even then only during a full moon. In combination with an 11-ant memory and a small pinch of other tricks, one arrives at results ranging from satisfactory to sufficient. I had the thread https://www.hausbau-forum.de/threads/Wasser-dringt-ins-Haus-Kern-Haus-duotherm.18308/#post-168435 quite on my radar for this question, but for a very simple reason I did not link it here: namely because, in my opinion, experiences (pl) require a somewhat broader spectrum. After the OP , it was especially as an affected party who contributed to the thread, followed by – all users I had not otherwise encountered here and whose statements I therefore find difficult to assess; at the beginning there were also responses from the affected company. What I have not come across are statements of similar problems in other forums – and, as mentioned, other statements from the aforementioned users that would make them assessable for me. So I lack evaluation here, which is why I refrained from linking this time. Additionally, the headquarters of Kern is geographically in my local area, without me having heard anything negative about them "from the butcher’s shop" here. That also leads me to consider the mentioned thread as probably representing rather isolated cases.