Why do metal tiles used in farms also need an anti-corrosion layer on the back?

The farm environment is usually humid and contains corrosive gases, such as ammonia, which will accelerate the oxidation and corrosion of metal materials. If there is no anti-corrosion layer on the back of the metal tile, moisture and corrosive substances can easily invade from the back of the tile, causing metal corrosion, thus affecting the service life of the tile. Therefore, adding an anti-corrosion layer on the back of the metal tile can effectively prevent corrosion, extend the service life of the tile, and ensure the structural safety and durability of the farm building.