Asked on May 12, 2014

Musty odor from fireplace, chimney is capped.

by Carmen
The fireplace in a townhome we recently purchased is not useable,and making it u to code is beyond our finances. To avoid animals coming down the shoot and a drafty home, we wereadvised to cap the chimney. After removingdebris, the chimney was caped, but we now have a musty odor in our living room.The shoot was checked again, and seems clean, so it was capped again, but thereis till a musty odor, especially when it rains. Suggestions please!
Jacksonville, FL
  9 answers
  • Adrianne C Adrianne C on May 12, 2014
    The outside of the chimney bricks probably need to be sealed, they may be absorbing water when it rains.
  • Carmen Carmen on May 13, 2014
    Thank-you @Adrianne C .
  • Moxie Moxie on May 14, 2014
    I would be suspect of the flashing at the chimney to roof joint. This is a common place for water to sneak in and could allow water in to creat smell and now that aur is shut off may be why you are smelling it.
    • Carmen Carmen on May 14, 2014
      @Moxie Thanks Moxie. Bothresponses point to water/moisture creating the problem. Any idea if a roofer would be able resolvethe problem? Or do I look for someone who cleans chimney.
  • Most townhomes use metal chimneys these days, but it is a moisture issue that is causing this odor. I would suggest that you get the chimney professionally cleaned as the older soot that is within the pipe is reacting to moisture. However assuming you do have a brick chimney and you are experiencing this odor when it rains, you need to look up inside of the fireplace with a strong flashlight to see if you observed water running down inside the flue liner or the brick. You may need to parge the brick surface that is exposed to the exterior of the house to lock out moisture from getting into the house. Moxie is also correct about flashings., A roofing contractor and or a good qualified chimney sweep is who you should be consulting with. My only other concern without knowing much about the construction of the fireplace is are you sure the odor is coming from it or perhaps somewhere else near it. You can purchase styrofoam and fit it into the face of the fireplace to seal it off. This low cost method will prevent damp air from dropping down into the house. If its indeed from inside the flue the odor will diminish quickly
  • Moxie Moxie on May 15, 2014
    A roofer, but a good one, flashing problems are caused by poor installation in the first place and chimmneys are common areas of error.
  • Carmen Carmen on May 19, 2014
    Thanks for the ideas. We are exploring all the suggestion, one at a time. DH checked flashing, and he doubts if that is the problem. I am looking for someone to clean the chimney tube(?) and hopefully this will solve the problem, that makes a lot of sense to me. Debris was removed, but the shoot was not cleaned, and it has gunck around it. However, thus far haven't found anyone - this is Florida. As far as sealing the bricks - how is that done? Anyone have other suggestions Judy.
  • Do not seal the brick. It will destroy them over time. Brick is designed to breath so if it gets wet it will dry out. Brick sealing agents are a clear liquid. They do not properly fill every hold and crevice because of that fact. Because of this water will still get behind the brick in many locations preventing this natural drying. The result will be spalling and chipping of the brick surface that is exposed to the weather. If the liner for the brick chimney was not cleaned that is most likely the odor your having. They make seals that can be installed just below the interior damper that will stop air from dropping down along with odors. But I suggest that you first try an experiment. Tape a plastic sheet over the front of the fireplace tightly and see if the odor goes away. I that occurs then a chimney professional needs to evaluate the fireplace and chimney and clean it properly. If the odor does not go away you need to look further around that area for moisture issues.
  • Carmen Carmen on May 19, 2014
    Thank-you. Yikes I would have gone from bad to worst!
    • @Carmen Yes your correct. There are many brick sealing products on the market and non of them work as they state. They do seal the brick, but they do not fill the cracks and voids because the product is to thin. And even if they were able to successfully achieve a seal, in a few months tiny openings would return due to expansion and contraction of the brick materials as well as the movement from winds and weather related issues. The result would be in some areas water would enter but the sealer would prevent it from naturally drying out.
  • Susan Bishop Susan Bishop on Jul 14, 2015
    It is not a shoot [sic], nor is it a tube. The shaft of a chimney is correctly called a flue. Here's a limerick to help you remember: A flea and a fly in a flue, were imprisoned, so what could they do? Said the fly, "Let us flee." Said the flea, "Let us fly." So they flew through a flaw in the flue.