Compression tape between cladding and window with air gap

Hello,

my windows (new build) are currently being installed and I have noticed that there is partially a 2mm gap between the compressible sealing tapes [Kompribänder] and the window frame as well as the facing masonry. So the [Kompriband] does not lie properly at all.
I spoke to the window installer about this and was told that the [Kompribänder] are only intended for sealing during the construction phase and that the joint must be sealed later. Only the sealing would be properly watertight against driving rain.
The [Kompribänder] would dissolve after a few years.

However, they would probably insert a different tape (compressible sealing tape as a "sausage" or something) from the outside afterwards if I wanted it that way.

This is actually completely the opposite of what I have read about window sealing.

What do you think? Do you have anything I can counter with that corresponds to the recognized rules of technology? I actually wanted to suggest to him that he remove the frames and use a thicker [Kompriband] so that it is properly sealed.

Thanks

Here is a picture once again. The other pictures didn't turn out... it was probably still too dark.

which corresponds to the recognized rules of technology.

Recognized rules of technology include an internal air- and diffusion-tight sealing, complete filling of the window joint with insulating material, and an external diffusion-open, air- and driving rain-tight sealing.

In addition, there are the specifications of the RAL Quality Association for Windows, which are not mandatory for installation. However, these specifications ultimately correspond to the state of the art but are supplemented by certain execution methods of sealing. Some manufacturers then label their products "for RAL installation," which means that RAL has included this product in their list of possible products for correct sealing. If these requirements are to be explicitly met, this should be clearly stated in the order or offer. Alternatively, other sealing methods are possible, but all should be executed as described above (only the RAL seal is not mandatory).

The stop tape for external window sealing is state of the art and also accepted by RAL. The important part here is the execution, which appears defective in your case. The tape swells after installation (24h). Afterwards, it should lie flush on both sides (window and wall). This does not seem to be the case with you because the tape was either chosen too thin or the windows were screwed incorrectly. Airtightness is then not guaranteed. PU stop tapes (compression tapes) are UV-resistant and do not crumble after a few years. If your window installer now wants to cover up his botched work with an additional tape, I would advise against it. I do not know whether inserting something else (?) into the open joint is permissible anywhere. In case of doubt, ask the manufacturer—if the window installer absolutely refuses to do so—and get confirmation that the tape does not have to be fully relaxed and flush on both sides (still slightly compressed). An additional sealing is then not necessary—only if the joint is to be visually concealed.

Alternatively to the stop tape, there are external window sealing strips with or without plaster lip, depending on whether it is a clinker or plaster façade. However, these are only used if the windows are not rebated on the masonry inside and insulation is applied in front of it, or in renovations.

Since you have a facing stone façade and a new building, I would insist on correct execution of window installation with a single-layer stop tape on the outside.

Addendum to the picture: Yes, this is botched! Pastings a strip in front of it now is makeshift work! Sealing it fully with 3 cm silicone is ... NOT ARdT, because silicone is not permanently durable.

When using compressible sealing tape, also pay attention to the manufacturer's specifications. For example, it might say something like "20/4/14," which means that the tape is 20mm wide, 4mm thick in the compressed state, and can perform its function (rain tightness) up to an expansion of 14mm. In fact, the tapes stretch further than specified, but they are no longer approved beyond that.

It can therefore happen that the tape visually fills a joint of 25mm, but is only approved up to 15mm. This means that even if the remaining gap were filled with something else (botched job, see ), rain tightness would no longer be guaranteed in this case.

I would also not accept the execution above if I were you. In the case of the facing brickwork, there will still be a layer of insulation and air behind the bricks. The window installer apparently did not feel like installing the windows in this insulation plane (which would be energetically and building-physics-wise appropriate!), because it would have involved extra effort (mounting stop angles or the like), and as a result you now have this offset, which apparently could no longer be bridged with the existing compressible sealing tape.

Thank you for the detailed information. The offset is caused by the angled rails at the window lintel. They protrude slightly inward (into the air gap). Therefore, the window installer could not bring the window closer to the cladding, as the roller shutter guide hits the angled rail. They probably should have used a thicker compressible sealing tape.

Hello,

I wanted to report and ask a few questions.

Some of the compressible tapes were replaced, but the installers still need to make some corrections.

I took a few pictures and would be happy if you could write something about them. After the issue with the compressible tapes, I have become a bit uncertain about our window fitter.

1. Middle level:
Here you see the fleece, which was glued from the inside to the frame to ensure airtightness. There is absolutely no insulation or mounting foam applied here. When the windowsill is installed in front of this, do I have a tremendous thermal bridge!?


Here you can see how the sunlight shines through the fleece from outside.


2. Screw through sealing

All the fastening anchors are screwed through the fleece. Is this still airtight?


3. Fastening anchors
This is probably just an optical issue, but I haven’t seen this before on any window. The screws are all visible from the inside. My wife is not very happy about that.


4. Window seal
The window seal is somewhat deformed on some of the windows. Is this just optics and a dirt catcher, or does this have to be tolerated?


5. Roller shutter box

The roller shutter box extends too far into the room. I will have a construction of 12mm OSB + 12.5mm drywall. Now the window fitter told me that only drywall would be applied to the roller shutter box, and no OSB. If that is the case, OK!?! But unfortunately, some roller shutter boxes stick too far into the room. If the drywall were mounted flush with the rest of the liner panel, the edge (marked green) of the maintenance opening would protrude several millimeters (up to 1 cm) beyond the drywall into the room. What still has to be tolerated here?


Thank you very much!