Basement fills with smoke-fireplace on 1st floor

Ct., United States   

Wood stove in basement not used- when fireplace on first floor is lite the basement fills with smoke- what is the problem?


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by ChimneyChick | March 02, 2015 ChimneyChick's avatar
Midland, Ontario

you do not say whether there is another fireplace in the basement and that the upstairs chimney is a single or double flue.
IF it is a double flue and you are using the upstairs fireplace, the colder weather may be pushing the smoke down the second flue by Thermal Convection. Your house needs to breathe and it tends to do this from any lower area [negative pressure zone=basement]
If this is the situation and you are not using the basement flue or it is a dormant flue, seal off the second flue temporarily with a garbage bag and see if that stops the problem. If YES, then place a permanent seal on the flue top.

by ChimneyChick | March 02, 2015 ChimneyChick's avatar
Midland, Ontario

If not then you have other issues and you may have a crack in the waithe wall separating the two flues. and it is time to contact a qualified sweep to attend the house
If it is a single flue, there again may be a break in the clay flue tile lining and the smoke is being filtered down to the negative pressure zone in the basement.  Can you possible lite the fire and then have someone stationed in the basement to see if they can see where the smoke is coming from??Again, contact a qualified sweep to assess.

by Tim Howell | March 06, 2015
Baltimore, Maryland

This is most likely the result of differing pressure plains in the home. On the first floor the pressure is neutral, the higher you go in the house, the more positive the pressure. And the lower your go in the home, the pressure is more negative. So when you have a fire on the first floor and not in the basement, if the flues exhaust close enough to one another, the negative pressure of the basement flue can draw the smoke into the basement. An easy fix is to offset the flue terminations. Have the first floor fireplace flue extended with terra cotta and masonry, flue cap extender, etc. A certified chimney sweep should be able to help you with this fix.

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