20 typhoons a year is a lot of typhoons! How did this land (through the course of history) ever become habitable? Or have the typhoons been increasing in frequency in the recent past?
Typhoons are usually not that bad, it just means a lot more rain in an already very rainy country. Traditionally it was dealt with stilt houses and so on. Today you would just deal with it by having houses elevated about 6m and your first floor being able to withstand flooding for the worse possible typhoons, which means a stone floor and a concrete house.
