ᐅ Facade discolored after 4 years

Hello everyone,

I understand that getting a clear answer on a forum and thus a remote diagnosis regarding a dirty/discolored facade is difficult, but maybe with your help I can make some progress.

We are already involved in a legal dispute with the construction company over some other defects (the base “iscoming loose,” soaking wet external claddings, etc.). Our lawyer advised us to repaint the facade at our own expense, as only a complex and costly laboratory analysis can really clarify the cause.
We will have a master painter come to take a look, maybe he can identify the cause.

Facts:

• Single-family house
• Facade painted 4 years ago, nighttime temperatures were around freezing, according to the construction company, it was painted three times
• Partially no roof overhang
• Barge flashing

Facade construction:

• Insulation material: mineral wool
• Base coat: water-repellent reinforcement mortar
• Top coat: water-absorbent plaster
• Silicate paint: hydroactive (biocide-free)

(I hope this is all correct!)

At first I suspected the barge flashing; by now I think it is a combination of the facade paint and the metal flashing. The facade beneath the gutter is also dirty; where there is a roof overhang, there is no discoloration.

I have a few theories but will keep them to myself for now; however, I do have two questions already:

• When you rub your hand over the silicate paint, it powders off finely, very finely. Is this normal?
• I don’t trust the construction company at all and also don’t believe they actually painted it three times. Is there a simple way to verify this? How does multiple coats affect the quality or performance (for any function) of facade paint, aside from coverage?

I will, of course, also post photos of the facade here.

Thanks very much in advance for hopefully some answers!