(Rising?) Moisture Base / Exterior Wall

No idea. If we knew that this was wrong. Actually, no ventilation is provided in the system...

It's really an interesting matter. So the rubber only sticks on top? Then it only protects against splashing water. Ground moisture that rises at the base plate can still penetrate. Then the moisture protection near the base is missing (the WDVS should be plastered with moisture protection from the manufacturer 5cm above [gok]). So you actually have two problems which, in my opinion, the curtain does not solve because it is not high enough. Also, bitumen is not UV resistant and therefore cannot be prevented in direct sunlight. The red panel is already a Styrodur. If you now remove the gravel strip and dismantle the curtain and glue the gap well with Styrodur and plaster the whole thing with 2 layers of moisture protection, e.g. Flexyl from S T Obi, is 5 cm above ground level okay? It can also be painted in facade color. Every manufacturer has that in their range. Could that be a functioning but not overpriced solution? What do the others think? The fact that dismantling and constructing the base according to standards is the optimal solution is of course beyond question, but we are looking for a good compromise, right?

Unfortunately, I cannot fully answer your question, but just today our roofer was here and sealed the perimeter area. The thing is, when building with a wood frame and wood/fiber exterior insulation system, you don't just build a wall back, you build the house back! That's why a consistent moisture barrier there is so important. Of course, it starts with constructive protection. So the "feet" of the house should not stand in the "dirt." Drainage + gravel bed around it already helps a lot.

Here are some pictures from today. The lower black area visible in the first picture, from about the wooden strip to the insulation under the BP, will be insulated with 30cm XPS perimeter insulation, sealed again, and finished with base plaster. The thin black foil on top is only to protect the facade from the weather until the plasterer arrives.

Hello everyone and thanks already for the previous answers.

Emptying and lowering the splash guard off-road and removing the rubber hanging in front of it are definitely two things we will do in the short term.
When sealing, it would probably be optimal to remove the Styrodur from the base plate in order to better seal the transition between the base plate and the exterior wall.
We are currently only concerned that if we seal it properly, it might be wrong afterwards because it might need ventilation, and then it would be too tight. Although the company Opitz, from which the system originates, says that no ventilation is planned and that it is a closed system, with the ETICS of course being a construction-side service...
Yesterday I also looked behind the Styrodur at the base plate. Then you can also see that at the lower edge of the exterior wall there is first a white base rail (presumably the lower edge of the wood) and then below the wood fiber insulation board the perforated strip and the visible reinforcement mesh (where the moisture probably gets in and is currently nicely held like in a sauna by the rubber).

The biggest problem is really knowing: What is right now and what is wrong? If we now spend money, we don’t want to be stuck there in 2-3 years regretting and realizing it was wrong.
All of this was done by companies - no own improvisation or such. Of course, that also loses trust...

Why do people actually install ventilation grilles?

That is not a ventilation grille?? I see a corner angle with mesh, it should have been sealed with reinforcing adhesive. Even better, a profile with a drip edge belongs there. What kind of plaster and paint do you have on there?

Yes, so if that is not a ventilation grille, which fits Opitz's statement that it is a closed system without rear ventilation, it probably must/may be sealed/tight. Maybe that would already be the solution...

There is continuous window putty, thickness 2-3mm, no base plaster, painted with Capatint Muresko Silacryl Basis 2 on top. In the end, treating the base area with Sockelflex or Deitermann or whatever is available and repainting would also be no problem. But that would only protect against splash water and the like and not against rising damp, I think?!