Re-clad a spotted facade?

They are not grouted; they are placed into the wet adhesive and then smoothed over with a brush, that's it. The strips are really thin, that's why it works. Nothing should tear, the ETICS has reinforcement anyway. By the way, the strips are elastic and become hard in combination with the adhesive. You can also take a look at a finished glued sample area at the hardware store. So I like it, even though I actually prefer natural stone look. But that is just too heavy for an ETICS (even if it is fastened with disc anchors and also glued).

A few days ago, I applied algae remover using a pump bottle. It worked quite well. However, the gable wall was still partially covered with brown stains that come from the roof tiles when the rain splashes color and dirt onto the gable wall.

I don't want to just buy something blindly, I'd rather ask you first, especially since I couldn't find anything in the hardware store today. Is there a concentrate that I can dilute with water to spray on the dirty areas and that also carries out the cleaning work on its own, as one knows from algae remover?

This is not a building defect, this is saving at the wrong end, or simply ignorance. For some, it happens during construction, for others during car repair or whatever. Depending on the adhesive and reinforcing mortar, one can often save the use of dowels. If the insulation, besides the plaster, has to bear additional loads, e.g. natural stone windowsills, then dowels are used pointwise.

Microcracks exist in the plaster, which can expand more or less depending on the material thickness and can absorb moisture. Where the dowels are, the mortar layer is thicker, hence the unevenness. This often happens when the plaster is not painted afterward.

Good results are achieved by painting the facade after the plaster is applied, for example with a "lotus effect" paint from a specialized retailer and having algicides and fungicides mixed into the paint at the store. The lotus effect ensures that water adheres less to the surface and algicides and fungicides ensure that no algae can grow on it. And paint twice, then everything has been done properly.

The money for the dowels would have been better spent on good paint. Lotusan G is, for example, a good paint, but there are other good ones as well.