Is PU foam between the sealing tape and window normal or not?

So, now I have to chime in as well. I am new here and stumbled across your post by chance. I am a master carpenter and managing director of my own GmbH, and I regularly install plastic windows. It is important to know that there are several ways to install a window according to RAL or the state of the art. The pictures you showed are simply a disaster. What was written about it is unfortunately not entirely correct either. Basically, the RAL installation stipulates that the connection joint must be tighter on the inside than on the outside. On the outside, the window must be resistant to driving rain. In the installation you showed, a Trioplex tape from Illbruck or an alternative manufacturer was used. This tape covers all three layers in one (driving rain tight -> insulation -> vapor tight). The joint must not exceed the manufacturer's specifications at any point, otherwise tightness can no longer be guaranteed. (1st defect). In addition, foam was used for the reveal, since the windows were obviously measured too small (2nd defect). However, the foam does NOT guarantee VAPOR TIGHTNESS. That means the window would be absolutely NOT tight, even if the tape adhered everywhere (3rd defect). Furthermore, the tape was folded around the corners of the window frame. This should not be done because the tape cannot properly unfold at these points. Instead, the tape must be separated to neatly connect again on the other side with a small overlap. This ensures proper unfolding. (4th defect). Basically, based on the photos, I conclude that the windows have to be completely removed and freshly (and properly) installed again. In my opinion, you do not need an expert initially for this, as these defects are MORE THAN OBVIOUS. Don’t let it get you down.

Since I am currently very stressed professionally and am also doing the electrical planning on the side, I had suppressed the window problem. The window fitter should receive the window contacts next week, which will be additionally installed for the tilt position (replacement is not possible because of the wrong position). Then he also wants to finish the rest. I had an acquaintance who has been a construction manager for several years and he talked the situation down a bit. He said that with my 1960s hollow blocks (24cm), it wouldn't make much difference anyway if it wasn't installed optimally. With additional façade insulation, it would be different. He only checked with a lighter whether air was coming through somewhere and pointed out a few spots, which are absolutely a no-go. Unfortunately, he also communicated this to the window fitter in this way. Only these spots are supposed to be scratched out and fully foamed. However, everyone who knows about windows says that the installation is absolutely a no-go. In my opinion, this is also obvious to a layperson, otherwise I wouldn't have had doubts from the very beginning. Let’s assume it is left as is and I simply do not pay for the installation (I doubt that it will be done properly even after reinstallation by this company), what problems can I expect? Please also consider the old masonry.

For what reasons do you want to keep the windows in? Just because you are busy with work? It probably wasn't cheap, was it? So complain about the installations and have the responsible service provider deliver the service you paid for ... period ... Since all the errors are obvious things, give written warnings etc. only by registered mail etc. and demand replacement and proper installation ... if necessary, also through a lawyer ... What can happen? Rot, mold, etc. ...

As I said, I have concerns that this company will do everything correctly when reinstalling the windows. Or even cause more damage. For example, not properly scraping out the old foam, damaging the windows, or making another error. Since rot or mold is really a problem and not just a possibly low insulation value, I have now asked him to correct this. He wants to fix the 9 windows plus the patio door in one day... I see careful removal as more critical than reinstalling. So that he doesn't make another mistake, I now want to tell him how he should do it. I assume the best solution would be to plaster the reveals thicker and then use the tape. However, this will certainly not be possible in this timeframe. Therefore, my question. In most places there is about 3 cm of play. What would you suggest? 1.) Instead of using the Würth Vkp Trio 66/5-10 used for the actual gap, take the Würth Vkp Trio 66/13-30 and just install it (this would certainly be the worst solution) 2.) Insist on plastering? 3.) Joint sealing tape: open to the outside and tight to the inside and foam on top. However, I don't have [WDVS], but my window opening does not have the same width or height throughout. So up to about half the depth as shown in the pictures and then tapering further. So that the outer frame is still partially covered. What must be considered here? I also have another question. He said that the lower window sill profile is only intended for aluminum window sills (I told him from the beginning that I want granite window sills). He wants to spray a 2 cm silicone layer there to compensate. I'm not a professional, but that sounds like botching again. What should he properly do? Change the profiles? I would really appreciate it if you could help me with this.

Which area are you from? There might possibly be another window installer? Unfortunately, I am not a professional either ... but I would quickly get an expert or similar BEFORE he starts with the repair/correction.

Just the thing with the aluminum windowsill instead of the desired granite sill would well ... it sounds as bad as: failed task - mark 6.

So .. get help ... ask another window installer etc.

I come from near Darmstadt. During the search for window installers at that time, there were also some on site. After the botched job, I also called a few to take a look at the matter and possibly correct it. I had also offered money for the inspection. Unfortunately, no one was willing to do that. On the one hand, no one wants to judge another's work, nor do they want to do anything with windows installed by others.

How do I get in touch with an expert? Who should I contact for this?