Dear Home Repair Enthusiasts: I live in a rambler-style house built in 1965, with two wood-burning fireplaces, one right on top of the other, with two flues right next to each other (see pic below). The upstairs fireplace works absolutely fine, but there are two problems with the downstairs fireplace, in that it smells of smoke: 1. When the upstairs fireplace is on, it smells like smoke downstairs, even when the downstairs damper is closed and the downstairs fireplace doors are closed. The reverse does not happen – when the downstairs FP is on, it does not smell upstairs. 2. When the downstairs fireplace is on, it also smells like smoke downstairs, but really badly, so that even my clothes smell after I use it, and the room smells for weeks afterwards. (Yes, I check the damper before using the FP ) I have CO and smoke detectors, which have not gone on, it’s just the very strong smoke smell, but not smoke. I had a chimney inspection done and chimneys cleaned when I bought this house three years ago, and they recommended the following: "1-2) Due to the missing mortar joints and gaps in the terra cotta flue liner, it is recommended that the tile be broken out and the flue be relined with an appropriately sized stainless steel liner. This recommendation applies to both the upstairs and downstairs fireplaces. 3) Due to the exposed hollow-core bricks and corbelling in the downstairs fireplace smoke chamber, it is recommended that the walls be parged smooth with high-heat refractory cement. 4) Because of the cracks in the concrete crown at the top of the chimney, it is recommended that a crownseal be applied to the surface of the crown in order to prevent further damage." The cost for all of this was $11K+, so I passed on the repairs. My questions for the forum are: 1. Why would it smell like smoke downstairs when the upstairs FP is on? Is this because of some sort of a downdraft because the flues are next to each other? Any way to prevent this? 2. What are some of the main reasons it also smells downstairs when the downstairs FP is on? Most of the smoke does come out through the flue, but the smell is still very strong. 3. If I were to replace the liner just in the downstairs fireplace, would it fix the problem? Is the price quoted to me reasonable? 4. Is there a cheaper way to fix this?