The plaster has discolored and is peeling off

Hi - it is actually only in the reveal area - at least currently only visible there. I suspect that it is rising water. Water must have run down between the door threshold and the paving slabs. Since the ledge for the floor slab is located there (this is sealed at that point), I think it has accumulated there and then - with a sufficient amount - gradually pulls the plaster up from the side.

The transition between the floor slab and the plaster was probably not sealed separately, so the damage likely occurred there.

Currently, the moisture measurement on the wall has not shown increased moisture. Therefore, I currently suspect it is only superficial.

I have included a picture from another location (patio door) of the house so that the transition between the floor slab (which probably has a fleece) and the house (or rather plaster) becomes visible. There, you can see at the corner under the window frame that the joint between plaster and wall structure is probably a weak point where moisture can penetrate the plaster.

What do you think about it? Can the problem be permanently solved with a seal between plaster and floor slab?

Thanks for your assessment Andreas

In this situation, I would probably just seal the corner area and see what happens. Ideally, you would make sure that no water can remain there, so basically round off the corner. But then you might need a different material again.

From a purely pragmatic point of view, that would be my idea - but it won't be compliant with the standards, will it?

In that situation, I would probably just seal the corner area and see what happens. Ideally, you would make sure that no water can stand there anymore, so basically round off the corner. But then you might need a different material again.

I think that when you start following the standard, it becomes more costly. However, I doubt that it will bring much more in this situation. If only the reveal area is affected, seal it off and make sure that water cannot remain standing in the corner. It is always difficult to judge from the photos. I would choose this minimal solution for now. The current damage in your case is also not that big. Unfortunately, you never see enough in the detailed photos; sometimes an overview from a distance would be better. I have now seen that you wrote something in another post. Consider my personal opinion specifically regarding the reveal area.

At least the visible damage. What happens underneath can't be judged without looking underneath first.

Thanks for your assessment. How do you come to the conclusion that it is not that high?

I think if you start going by standards, it will be more costly. Whether that then brings more benefits, I dare to doubt in this situation. If only the reveal area is affected, seal it off and make sure no water can remain standing in the corner. From the photos, it's always hard to judge. I would choose this minimal solution first. The current damage to you is also not that big. You never see enough in the detail photos unfortunately, sometimes an overview from a distance would be better.

I have now seen that you wrote something else in another post. Consider my personal opinion related to the reveal area.