And on the subject of sharing renovation ideas.... If you don't need to have a fireplace, I think that I would install a modern double-wall stainless chimney (or at least a flexible liner) inside of your existing flue, rather than try to fix the flue you have. Then you can still have the look of the old-fashioned stone flue, but not have to worry about burning your house down.... Seriously man, there is an old house that burns here every year from bad flues......

It is expensive to buy the liners or stainless chimneys, and I definitely like to do things on the cheap whenever possible. But there are two places where I think it does not pay to do a bad/cheap job: Foundations/sills and chimneys. Doing both of those right is expensive, but still way cheaper than building a new house when the old one falls/burns down, hehe. :3