I imagine fireplace odor is a common topic on these forums but so far I haven’t been able to find any answers online that address my specific situation. I have a wood-burning fireplace in a 1952 house. The chimney is not on an external wall, so I get a good positive draft even with no fire. However, after burning, I get a decently strong ash/soot odor that doesn’t go away. Interestingly, this ONLY happens when my top-sealing damper is CLOSED. If I open the damper even just a crack, the smell seems to dissipate pretty quickly. But, obviously, I’d rather not lose all that heat when I’m not burning a fire. I have glass doors on the fireplace (not really airtight). Given the top-sealing damper, it seems unlikely that I have a downdraft when there’s no fire, so it must be that the smell of the chimney is leaking through the glass doors. Does anyone have a suggestion for how to prevent the odor? Should I make a block-off plate to insert above the firebox when I’m not burning a fire?

Thanks,
Dan

You must have creosote build up in the smoke chamber and flue. when you are burning add some ACS (creosote remover) it will dry out the creosote so it can be swept out. This can be somewhat of a long process 20+ fires. Also make sure to use nice dry wood, wet wood makes for a stinky fireplace.