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Chimney & Fireplaces/Upstairs fireplace back drafts smoke down basement fireplace flue


Hi, we have a home with an upstairs and downstairs wood burning fireplace.  The share the same chimney, but  have separate flues.  Whenever we have a fire upstairs, smoke backdrafts down the basement flue.  The basement flue door is closed.  What can be causing this issue and how can it be corrected?  Thanks for your help!

Hello Dan, this a very common problem, when you have 2 fireplaces the one you are using needs to draft, lets say 10 gallons of air per minute going up the chimney, then it needs 10 gallons of air per minute from the home and in most cases it will pull that air down an other fireplace flue this is called “make up air”along with smoke, 1st make sure the damper is closed on the un used fireplace, close off doors to the other fireplace area (basement doors), leave a window open on the lower level, install top mount damper caps on both flues and close the one you are not using and open the one you are, I would have a local Certified Chimney Sweep, (there you can look up by zip code to find one near you) take a first hand look at what you have, they should be able to help.
Hope this helps

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James Ball


I am a chimney sweep with over 22 years of experience, CSIA certified and member of the NCSG, I can answer questions about smoky fire places, wood stoves, and heating units (boiler and furnace chimneys) do you need a relining? A cap? And much more


over 22 years

Chimney Safety Institute of America, National Chimney Sweep Guild

CSIA (Chimney Safety Institute of America) certified

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