I'm in the midst of trying to figure out what the problem is with my fireplace. Last year I had a chimney sweep out and he mentioned nothing about any structural problems with the fireplace yet I continually have problems with it belching smoke into the house. The house now has double-pane windows all around so there probably has been a decrease in flow. I also have a T.V. antenna that is only about 6 inches above the top of the chimney. The flue is definitely offset from the fireplace front which seems to render half of the damper useless. Are chimneys that have offset flues a hopeless case or is there something that you can suggest to fix the problem? Thanks. Brian W.