They used what was at hand. If they had lots of timber, it was used. Good sod, it was used. Peat, it was used. Any and all combinations can be found. Some by necessity, and some by choice. The tried and tested being used in combination with new theories put into practice.
Hillside abodes were brilliant in their simplicity. Now, this is conjecture on my part... early man needed shelter. Caves were natural shelters. Then shelters evolved as needed, where needed. I equate some of these hillside abodes as a direct engineering descendent of the cave theory. The ground is a good insulator, it remains steady for the most part. It tends not to rot. It is earth. It occurs naturally meaning less work to construct. Find a good location, add what you need to for it to be functional. Presto... dwelling.
The portable structures was new to me. That does explain why so little has been found in some areas of settlements. So I guess even they had trailer parks so to speak. Not a bad idea all things considered. Move where you need to to better your chances of survival.
It actually surprises me how dry the turf homes remained. When we thing of turf, we think of it getting wet and soaking down in. Like watering yards and gardens. They had it together the way they constructed their roofs and dwellings to prevent massive flooding of their dwellings. An inner roof and exterior roof... ingenious! And their construction often allowed for growth as well making the turf more dense with time.
It seems we were not just the dirty kill crazed creatures some other cultures thought us to be. *W*
