Bought a sandwich roof, got a different roof?

You are building a multi-family house in Munich for several million and there is no one except the forum here who can answer your questions?

You are building a multi-family house in Munich for several million and there is no one except the forum here who can answer your questions?

I only purchased a small apartment in the development. And I just want to avoid bigger problems in the future.
As it seems, I am the only one questioning the measures. At least, I haven’t heard any other questions from other buyers. The developer also keeps the buyers nicely separated...

And I just want to avoid bigger problems in the future. As it seems, I am the only one who questions the measures.

Well, we are talking about an apartment here and not a Ferrari, which would suffer a significant reduction in its collector value due to hail damage. I consider the waves to be effects of thermally active material. Whether it wants to crack back to its original state in the height of summer, I cannot judge. I do not expect any leaks. I suspect that compromises were made here for scheduling reasons regarding the recommended thermal production and storage conditions, i.e., the sandwiches were produced without allowing the sheets and the insulation core to acclimatize sufficiently before processing and bonding them together. This is not normal - but I am not an expert who could tell you whether this (technically) is a drama or just a minor issue. The dents will not impact the resale value if the expert confirms them as purely cosmetic defects. However, as far as I know, I do not see any experts for this in the forum - probably at best or ...

Thank you for the link, but I also lack experience with the products. To my taste, it doesn't look right at first. Whether this will result in consequential damage due to defects, I don't want to judge now either. If you have bought an apartment, then there is an apartment owners' association. This association has certainly commissioned an independent expert for acceptance. I would ask this question to them.

However, I am also a bit doubtful about the topic of construction. The steel beams are likely to cool down due to the small covering and transfer the cold to the rough installation. A thermal bridge calculation would have to have been carried out, otherwise the reinforced concrete would also cool down locally, and condensation could occur on the floor below. But today's buildings all have to have such an assessment, so it seems to be okay.

Hello dear forum participants. Thanks to your many very good opinions, I have meanwhile been able to get the developer to make a statement:

…Since this does not constitute a defect in execution, and a wave pattern can always occur and is also permissible according to the specialist rules of standing seam technology. I would also like to point out that there will be increased wave patterns in now smooth areas during the summer.

This is partly due to the different temperatures of the sheet metal during installation and partly due to the expansion of the sheets at higher or lower temperatures. That is why it is also installed with so-called "sliding clips" that allow a certain sliding range.

However, since "fixed clips" must be used on roof windows and on angled cuts, these are fixed as the name suggests. The reason for this is that it pushes the sheet metal in a certain direction. This thus determines a controlled expansion in the desired direction.

However, if several of these points come together, and the sheet metal does not have exactly the same temperature, such a "wave pattern" can occur because the sheet metal adjusts differently after installation.

This is not a defect in execution and in no way impairs the tightness of the roof. Everything is interlocked, which practically makes the roof one large aluminum sheet. That is why it is also very difficult to replace anything here.

We have decided to replace this one less successful aluminum panel from eaves to ridge at great expense. The rest, considering the many adjacent components and the laws of nature, has been more than perfectly successful. There is nothing to criticize here.