Expert: James Ball - 12/20/2008

Question
We have three fireplaces, all in the same spot on three different floors.  The main floor firelplace burns beautifully.  The basement fireplace has not been used since we move in (six years).  We are refinishing the basement and I would like to test the fireplace.  I did a quick test by just burning some newspaper which seemed to work fine until the actual fire was gone and then the smoke started to come back into the room.  The temperature outside is approx. 25 degrees.  Could the "backwash" just be from the cold chimney?  What would you recommend as a more thorough test?

Thank you.

Answer
Hello Scott, 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 or an upstairs fireplace) 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 a open window in the basement? Or stop the air from getting out the attic.
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 doors)
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