Why does Sweden have many houses of a red wall? I had doubt about it. The information about the Swedish house is poor in Japan. The reason is because simple explanation is carried in the site of some import house companies.
I found useful information in Shöna Hus(JP) about Swedish houses.
The ingredient of red paint is ferric oxide. It has prevention of decay characteristics, and there is the durability, too. There is the Falun copper mine where a dig began at the ninth century in Sweden. This copper mine seems to have held 2/3 of copper production in the world at the time in the 17th century. Therefore, the paint (Falu red) has been used for a wooden private house for a long time in Sweden.
Falun copper mine was closed in old days(1992). There are the houses of the people who worked in the copper mine in old days. It is remodeled the inside, and those houses are used now. Those houses were built in old days more than 200 years. And they are very small. The cold resistance of the log house does not seem to have been so good.