Originally Posted By: mlong This post was automatically imported from our archived forum.
Certainly a flue liner is highly recommended, but you’ll come across a substantial number of old houses with chimneys that don’t have flues. That in and of itself doesn’t make it unsafe. (especially if the house hasn’t burnt down in the past hundred years.) It depends mostly on the thickness of the chimney to combustables and the overall condition of the chimney, whether there are cracks, etc. Without a flue liner I believe the recommended thickness of the chimney is 8". And certainly, any chimney with cracks that may allow exhaust into the house would not be acceptable.
Bottom line, though, if I come across a chimney without a flue, I'd recommend an inspection by a Certified Chimey Sweep with the equipment to examine the interior of the chimney.