I need to tie the stovepipe from my wood furnace into an existing terracotta lined chimney. The chimney has a 10"x10" opening cut in it, and the stovepipe I am using is 6" round. The question I have is, do I need to do anything special to make the connection between the two, or just run enough stovepipe into the chimney?? Please keep in mind this is all contained in foundation block work. See the attached picture for clarification. Any and all help is appreciated!!