the technique is just the same, sometimes for exterior frescos people add upto 10% of white cement for immediate strength, but that shrinks painting time considerably. Adding some brick dust does the same but better on the painting time.

In reality if building is not meant to last more the 200 it is not essential - because big "wear and tear" signs should become evident only after a long time (if the plaster is done properly). There are very well preserved exterior frescoes in Bavarian Alps that are over 400 years old.