Why are barns and other farm buildings usually painted red?
Barns are red because a few hundred years ago farmers started painting their barns with a mixture of linseed oil, milk and lime to protect the wood. Then they added ferrous oxide, basically rust, to the mix to kill fungi and moss. The ferrous oxide turned the mixture red. Painting the barns with rusty paint was the best way to keep them strong and dry. This would have been more a burnt orange red than the fire engine red we see today. Red barns became a tradition. And that’s why barns are red.
