There was a perfect example of the differences in structural types on the tv this morning. In Bromley, an house had crumbled into a hole leaving most of the front upstairs and the roof intact. The bits that had held together well were the carpentry and joinery -which of course holds itself as a unit.
Don't bother looking at the BBC site for a picture, they are down to their crappy worst there. (Until you see what is available via free enterprise. FFS!)