I found out why the color of the metal tiles in the bathhouse faded after 10 years

In one of my articles, I wrote that the metal tile on the roof of the bathhouse, which is already 10 years old, has lost its rich green color. Has become faded, as if faded. This does not happen with the metal profile on the fence (although it is 5 years younger).

I thought it was such a powder paint on a metal tile or such a batch of roofing sheets. Although, I purchased it from a large company, from a manufacturer.

Recently, for the repair of the deflector on the pipe, I went up to the roof and these color changes can be seen even better up close.

But as it turned out, it was not the paint that changed color, but the roofing sheets were covered with some kind of wash-resistant coating. It is possible that pollen from plants and trees has such a resinous structure that this matte white coating cannot wash away the rain and flake off when the snow melts. Near the site there is a forest. Dust adhered to the pollen, leaving the salts contained in it.

Insect tracks are added to this picture. Perhaps it is their deposits that are not washed off completely, but spread out, forming a film. And over the years, plaque has accumulated, changing the shade of the roof. In simple words, flies and bugs have dirtied the metal tiles.

Rubbing it with a rubberized glove, it became clear that under this coating paint with a natural bright shade of color (RAL 6005 moss green) appears.

I wonder if chemicals for a non-contact car wash will cope with this plaque? There is only one idea to wash it off - this is to apply foam on the roof with this detergent on a cloudy day and rinse it off with a high-pressure car wash (or just water from a hose).

So, questions about the quality of metal tiles are removed. Was wrong. If someone faced such a situation - write in the comments.