Hi everyone. I have a fireplace on my first floor and a stove in the basement. They share a common chimney ( separate flues ). I'm having a lot of issues with stack effect pulling smoke into my basement when using the first floor fireplace. Also have a pretty strong backdraft through the basement stove in general. I was wondering what the best solution is? Would adding a damper to the wood stove help? What kind of damper would you recommend? Thanks!
Basement stove stack effect solutions
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Are the flue tops exiting the chimney at the same height? If so, this makes it easy for smoke to siphon from one stack to the other. Adding an extension to the first floor flue can remedy this problem.
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The other thing to address is the negative pressure in the basement. Sometimes this is due to air leakage on the floors above. This could be caused by leaky windows, poorly sealed attic door, etc.
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The other thing to address is the negative pressure in the basement. Sometimes this is due to air leakage on the floors above. This could be caused by leaky windows, poorly sealed attic door, etc.
Thank you. Yes, they are the same height. I will look into the extension. My upper floors are sealed pretty well - had an energy audit and they sealed everything they could.
Even when the other fireplace is not in use, I can feel a cold draft inside the stove and have a bad smell which I think is from air escaping carrying odors from the ash. What can I do to help with that? I was looking into a stovepipe damper, but not sure if it will fix the problem. Thanks in advance.
Even when the other fireplace is not in use, I can feel a cold draft inside the stove and have a bad smell which I think is from air escaping carrying odors from the ash. What can I do to help with that? I was looking into a stovepipe damper, but not sure if it will fix the problem. Thanks in advance.
A stove pipe damper is going to slow down draft, even when open, so that may make the basement stove hard to run. If the chimney is on an exterior wall, that often makes the situation worse. Does the stove flue have an insulated liner in it?
The stack effect may be caused by leakage out of bathroom vents and radon fans, or other exhaust fans like the kitchen hood or the clothes dryer. If there is a furnace/boiler/gas or oil hw heater, they are also competing for combustion air. Sometimes the only solution is to install an adjustable HRV to slightly pressurize the basement room.
The stack effect may be caused by leakage out of bathroom vents and radon fans, or other exhaust fans like the kitchen hood or the clothes dryer. If there is a furnace/boiler/gas or oil hw heater, they are also competing for combustion air. Sometimes the only solution is to install an adjustable HRV to slightly pressurize the basement room.
OK, that's good. It was the strong backdraft comment I was responding to. Normally that means a balky starting stove or one that spills smoke when the stove door is opened. If that's not happening, the backdraft is not bad.
Came downstairs this afternoon to a basement full of smoke. Neither the fireplace or stove were in use. Looked into the stove and there were burning embers. Last burn was last night and everything was out. I think that the draft down the chimney reignited the embers and the stove was working in reverse - pulling air down the chimney and pushing smoke out the air vents. Argh. What to do?
This indicates that there is a serious backdraft issue with the stove. This is dangerous, it could be lethal. It is a separate issue from the fireplace smoke siphoning. See the previous post #4 on this topic.
My first thought is stack effect pulling cold air down the chimney for the stove, with leakage out into the stove room, up the stairs, and out through any upper story leakes (eg. into attic) or, in particular, through an open or poorly closing fireplace damper. Those dampers are notorious for poor closure. With the stove burning but not the fireplace, the backdrafting would be reversed. Maybe you could try taping a piece of cardboard over the fireplace hearth, sealing that potential leak as well as you can.
What worries me on top of the issues noted is that there is no mention of smoke and CO alarms (that should have gone off in the basement).
I would *NOT* use either of the two flues again until these alarms have been installed at least on every floor.
This could have killed you and those in your home.
I would *NOT* use either of the two flues again until these alarms have been installed at least on every floor.
This could have killed you and those in your home.
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