Originally Posted by Bill

A photo of the gap area where the walls join would help. However, caulking (rather than cocking) is for appearance (gaps are ugly) and for sealing (keep water out), but it is not a structural thing (hold things together). The fact that the outside is solid and tight would seem to say that the structure is solid and the walls are not pulling aprt, which is good news. Assuming this is true, I have no idea what is going on inside. Again, a photo would help.

Bill