Ok I think I was wrong blaming the bevel tool for this problem as
I continued my model when it came to fill in the roof. I encountered another problem which makes me think the source of most of these problems is the "Insert edge loop tool". When trying to select boarder edges to fill in the roof this is how the border edges where selected (see pic). Anyone have any idea what has happened here ??

Thanks for your time Guys !!

- Mike