also, support is distributed across all touch points. you can put up a temporary support and build a roof, for example, and once built the roof tiles touching each other add just enough support to let you knock out the beam you put in and they won't collapse anymore, like a house of cards all leaning on each other just so. However an unprotected home built this way will fall in if you lose the wrong tile in a raid, so you were warned ... its better to have strong support all the way up, by burying beams inside walls or raising a terrain point somewhere to tie off from, etc.
it is not worth trying to build tall until you have ironwood beams.
roofing is the most challenging part of builds.