I lived in the PI for two year, 1959 to 1961. I loved it and the people.
The Nipa Huts (houses), as I remember, were built up on stilts, higher off the ground than these in the photo. But, that may depend on location to sea level and/or the mountain areas.
Bamboo was always the primary building material for support and flooring. Woven grasses for the walls and palms for roof thatching.
Building materials were always available to anyone. The bamboo could be rather large for some structures. 6 inches in dia. was not uncommon. It maybe now however, and nearly imposable to get here in the States.
My best,
Blair