I think it's all about how you plan to build the house, what kind of structure. In time, i have heard it's much better then now days board roof, and tile. It's not from grass, actually, its from reed. And the roof cant colaps if the internal structure its being made good. Also a very good insulator, is the clay wall, basicly this type of masonry started to use reed roofs. Hope you will try it out..its really interesting..
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