It is not my intention to insult anyone, but is there a reason why people do not paint the outside of their properties? Growing up my dad used to say that by looking at the outside of a home, you will know how it looks inside.
Even if a house is old, painting it can make such a huge difference. I find that most buildings are so ugly.
I can’t answer your question (although I guess it’s due to humidity and mould), but your dad is unbelievably wrong. I’ve seen so many homes that look like crap on the outside but are amazing inside. This might be because I live in London where even ugly former social housing is very expensive. People make do with what they can.
It’s common in Taiwan, build it and never maintain, even inside. Wait until the old generation dies, then it’s time to renovate with the money you get from an inheritance. In the many years I’m in Taiwan I’ve seen few people redecorate a home. They just do the whole renovation thing after 30 years or, rip out everything and spend another million or two renovating.
Probably the same reason people never seem to scrub the outsides of pots and pans… 
Black pots cook better than shiny. It’s physics. Or is it ‘thermoscience’?
How does that work?
Try it out, put a shiny pot and a black pot filled with water on the fire and see which one boils first.
I’m asking for the mechanism. Heat conducting properties of grime?
Grime turns into blackness after heating.
OK, I give up…
Stiff udders?
Lack of an answer to my simple question.
Maintenance isnt of strong importance here unfortunately. It is what it is.
You must be new here 
Ok. Jokes aside. Even if they painted over the tiles, the paint would peel off in the next typhoon.
These buildings were also built for temporary shelter while the economy was growing at a rapid pace. The narrative back then was that Taiwan was gonna retake China and were not given any style.
We know how that worked out.
I can rephrase my comment in that people will redecorate/renovate their (family house) ever generation or so.
Sometimes it’s ownership issue. As in the building is owned by different owners. So who’s going to clean the outside? The management. Often the management fee barely covers elevators, security, etc. and unless they increase the management fee by a lot, they can’t power wash the walls every other month. And also on that subject, those mold builds up rather quickly. So people may just feel it’s no longer worth the trouble.
I saw new buildings in the South, single family homes, that had vinyl siding.
Not so easy to do that to a walk up or high rise.
Taiwan is a dusty place. Period. Why bother?
It’s very low effort. All of Taipei needs a big pressure wash. But the good thing is buildings constructed in the last decade don’t seem to look as grimey.