[Cob] Are roof overhangs absolutely necessary?

[Damon Howell]

Christopher: ...after seeing many pictures of old cob buildings in wet
climates...I have begun to question the common wisdom about the
absolute necessity of overhangs.

Damon: I have noticed the same thing. Many of the old buildings  
(actually, most I've seen) doesn't have but a couple inches of  
overhang. I would imagine you'd have to replaster quite a bit that  
way. But it's the English who say all a cob house needs is a good hat  
and good boots. I think a large overhang doesn't really mean it's  
gonna protect the top of the wall though.