When building a house into the side of a hill, I one should consider the durability of the hill as well as the house. Even if it doesn't collapse under its own

When building a house into the side of a hill, I one should consider the durability of the hill as well as the house. Even if it doesn't collapse under its own weight, it's not much of a hobbit house if you can't walk (or jump) on it. [Bad things](http://green.blogs.nytimes.com/2011/02/18/green-roof-collapses-in-illinois/?_php=true&_type=blogs&_r=0 http://green.blogs.nytimes.com/2011/02/18/green-roof-collaps...) [can happen](http://en.wikipedia.org/wiki/Zolitūde_shopping_centre_roof_collapse http://en.wikipedia.org/wiki/Zolitūde_shopping_centre_roof_c...) when green roofs aren't properly constructed.