Over the past week, David Pettegrew and I have been able to observe the various processes which caused a series of rural houses to collapse. One key issue is with their tile roofs.
A number of houses seem to have had their roofs systematically stripped of tile.
In some cases, the tiles slide off the roof as parts of the roof gives way over time. As the tiles slide off the roof, they frequently form halos around the house...
In other instances, the tile roof stays more or less in tact, but the walls of the house begin to splay.
In some cases, the home owner tried to buttress the wall with another wall, but this did not seem to work entirely in this case.
When the walls collapsed, the tile roof caved in on the interior of the house.
If the interior of the house doesn't get squashed by the collapsing roof, then the various interior partition walls (which were often just plaster and mud) collapse as well.