Yes, I know this sounds like a shitpost, just hear me out. I'm aware of the "commieblock" architecture throughout former communist countries and I understand that, it's cheap and somewhat reliable. But when scrolling through Google Earth, I noticed multiple cities in former communist countries like Phnom Penh, Ulaanbaatar, Pyongyang, Astana, alot of Siberia and Naypyitaw all have a much higher percentage of houses with blue roofs than the rest of the world, even communist countries in Europe. Is this an Asian cultural thing, was blue paint cheap? What inspired the communists or citizens to build so many blue roofs?
Interesting observation! While I wish there was a satisfying, unifying, historical answer to this - some indication that communist design institutes taught students to favour the aesthetics of blue, or correspondence between workers and urban officials settling on cheaper waterproof blue paint - the answer might be a bit more mundane.
I don't think there's a strong relationship between socialist architecture and the blue roof phenomenon, especially since Google Earth images tend to be quite recent. (I also suspect some of the roofs you're looking at might sometimes turn out to be green, reflecting the abundance of aluminum). I'll also point out that the 'commieblock' stereotype groups together a variety of construction styles and design philosophies, some of which are indeed more related (within the former Soviet republics) but others more disparate (Especially before 1988, Burma's postwar regime pursued a policy of autarky that intellectually and economically isolated it even from other socialist countries, something that extended to housing too). Finally, on your point of Pyongyang, we note that there are plenty of blue houses in South Korea and even Japan too.