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Chase for direct-vent fireplace

Post in 'It's a Gas!' started by ellenjo53, Feb 18, 2010.

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  1. ellenjo53

    ellenjo53 New Member

    Joined:
    Feb 18, 2010
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    Loc:
    Western PA
    We had a direct-vent fireplace installed on an interior wall in a newly constructed home. The fireplace leaks a lot of cold air at the bottom -- we've caulked around the soapstone face and taped where the gas line comes in. LSS, the chase is not enclosed -- it is open to the air space above this sun room area in our house, and merely has insulation (in the ceiling above) laying on top with the vent pipe passing through the insulation. The builder is trying to rectify this situation for us, but I'm not sure that he knows what he is doing. I've read about proper construction of a chase for direct-vent fireplace, but am wondering what the thoughts are in the Hearth Room. Many thanks.

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  2. begreen

    begreen Mooderator Staff Member

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    Loc:
    South Puget Sound, WA
    Moved to the gas forum for a more targeted response.

    Was this installation inspected? I would expect a metal firestop if the vent passes through floors.
  3. ellenjo53

    ellenjo53 New Member

    Joined:
    Feb 18, 2010
    Messages:
    2
    Loc:
    Western PA
    There is a firestop around the vent pipe, but the chase is open at the top. In other words, the firestop is installed around the pipe, but there are open gaps all around the firestop because the top of the chase is not enclosed. I've had our local building inspector look at it and compare it to the installation manual that came with the Heat & Glo fireplace. Heat & Glo says that the chase should be sealed and treated as a part of the interior of the house to prevent drafting. I am also reading (on a Vermont Castings website) that there should not be any exposed insulation inside the chase that could fall onto the firebox. In fact, this has already happened, and my builder is planning to "fish" it out of the chase. My feeling is that the fireplace needs to be removed, the wall opened up, and the chase constructed safely and properly. They want to attempt to fix it from the crawl space above the room by enclosing the top of the chase only -- no sheetrock on the inside. Any thoughts out there?
  4. DAKSY

    DAKSY Patriot Guard Rider Staff Member

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    Loc:
    Averill Park, NY, on Burden Lake II...
    You have a cold install on an interior wall? That's pretty uncommon.
    Externally installed units generally exhibit cold drafts which are
    in fact reverse convection air movement.
    If you install a gas fireplace on an interior wall, the only insulation
    required is in the ceiling above the unit & below the attic space.
    Plywood firedecks are required at every ceiling/floor level (8 or 9ft),
    with firestops installed in each deck.
    That being said, you should probably have an insulation shield where
    the vent pipe passes thru the insulated area.
    If you're getting cold air thru the gap between the firestop & the vent pipe,
    seal it with tape-style stove gasket or aluminum tape.
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