+ Reply to Thread
Results 1 to 4 of 4

Thread: Mysterious flue

  1. #1
    Join Date
    Oct 2007
    Location
    Bethesda, MD
    Posts
    3

    Default Mysterious flue

    I have a house built in 1951 with 3 separate flue stacks in the chimney - one each for fireplaces upstairs and downstairs in the basement, and one flue in the middle for the wood box in the brick right next to the upstairs fireplace. There is no smoke box; it is a straight flue.

    First, why would a wood box have a flue in the first place? It is evident that nothing has ever been burned in the wood box. If there is a good purpose for the flue I'd love to know (and maybe it would be helpful for something).

    Second, we discovered this had a flue after the first big rain - we could hear dripping in it. Turns out a previous owner put fabric over the flue and then just masonry over the fabric, so the fact there is a flue there is not evident from the top of the chimney. The chimney sweeps missed it too. The masonry is porous so water leaks into the flue and down into the wood box (which has a cover so the water just drips on there).

    The chimney sweeps want to completely redo the masonry chimney cap to prevent the leak. Instead, I took asphalt shingles and used roofing caulk and construction adhesive to secure them to the top of the chimney over the flue. So far, no more leaking. Any reason this would be a bad idea?

    Thanks in advance for any insight or advice.

  2. #2
    Join Date
    Jun 2007
    Location
    Fayette County, Ohio
    Posts
    5,939

    Default Re: Mysterious flue

    It's hard to guess why you have this arrangement unless there was a building chance during construction or there was originally a fire place on the first floor that was closed and the wood box was cut into it's flue.
    As for your "repair" a real danger would be if you have a chimney fire and it sets the asphalt roofing, roofing caulk, and construction adhesives on fire you would have that dropping down on you wood box.
    Jack
    Be sure you live your life, because you are a long time dead.-Scottish Proverb

  3. #3
    Join Date
    Oct 2007
    Location
    Bethesda, MD
    Posts
    3

    Default Re: Mysterious flue

    Thanks for your replies. I don't think my description was clear enough in my original post. The chimney (the brick structure) is 14 feet long. There are two stacks at either extreme end that go to fireplaces in the basement and the main level of the house, each steel stack about 8 inches in diameter. These stacks are taller than the brick structure. The whole top of the brick structure (besides the two stacks) is covered in masonry (from the link provided by DwarfWatch, the cap). Each stack has a cap and spark arrestor on top of them. In the center of the brick structure is a covered flue. The shingles are solely on top of that hole; the shingles are still not within 3 feet of either stack. The actual roof line is probably closer to the stack than the shingles on top of the brick structure. I appreciate both of your concerns, but I am not worried about the shingles on top catching fire - merely trying to seal this ineptly covered flue.

    The quotes I have received to redo the whole cap are $1500 and up due to the length of the chimney. Besides the open flue leaking, the cap is properly constructed and in good condition, according to the chimney sweeps I've had out to give estimates.

    On the main level of the house, there are two openings in the brick chimney - one is this "wood box" as I am calling it, as I cannot figure out any other purpose for it, and right next to it is the fireplace. It does not appear that anything has been burned in the "wood box" in the past 60 years as the brick inside is the same color / construction as the whole chimney. The fireplace has different bricks - flatter - and a smokebox before going up the flue.

    No ideas why there would be flue for this "wood box"?

  4. #4
    Join Date
    Jun 2007
    Location
    Fayette County, Ohio
    Posts
    5,939

    Default Re: Mysterious flue

    I still don't kmow why that open flue is there, but if the cap is in good shape I don't see why you would have to redo the whole thing. Go to a gardem center and get a concret paving block 2" thick and bigger than the opening, lay a bead of mortar on the cap around the opening, and set the paver in place . That should seal the opening and work as a perminant fix.
    Jack
    Be sure you live your life, because you are a long time dead.-Scottish Proverb

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •