Expert: James Ball - 1/7/2009

Question
We have a basement fireplace that we use frequently.  Randomly, smoke will not vent up and will fill our basement with smoke, leading to openning windows and venting it out.  I had a chimney sweep inspect it this summer and it was in perfect condition.  He was not sure if it had ever been used(we just moved in this summer). Why would we get this down draft randomly?  Would it make a difference if we had glass doors instead of a mesh screen?  Thanks for your help.

Answer
Hello Nick, What is happening is you are getting Negative Pressure in your home that is hot air raising in your home (and getting out through the attic vents, doors, lights) your house is a better chimney than your chimney. Also kitchen/bathroom exhaust fans, cloths dryers and the furnace all take house air out of the house (mechanical negative pressure) your house needs make up air, perhaps an open window in the basement? Or stop the air from getting out the attic and other areas.
Trail and error until you get this fireplace to work for you, maybe close off the room from the rest of the house to use it (close door to the up stairs)
Or it could be dirty? I would have a local Certified Chimney Sweep (www.csia.org, there you can look up by zip code to find one near you) take a first hand look at what you have.
James