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  1. #1
    Join Date
    Jan 2011
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    42

    Gas fireplace insert

    I have an existing masonry chimney with gas fire logs that I want to replace with an insert.


    - Should there be insulation around the vents from the inside of the chimney to prevent draft , and also between the insert the and masonry .

    I am getting different answers from the contractors.

    Any suggestion on an experienced licensed contractor around the Detroit metro area?

  2. #2
    Join Date
    Dec 2011
    Location
    PA
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    206
    Gas Insert or wood?

  3. #3
    Join Date
    Jan 2011
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    42
    Gas

  4. #4
    Join Date
    Dec 2011
    Location
    PA
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    206
    typically we insulate at the damper throat where the vent liners pass through. if the masonry fireplace is built properly you don't need insulation around the insert.

  5. #5
    Join Date
    Jan 2011
    Posts
    42
    What kind of insulation do you use...
    do you touch the vent with the insulation


    Quote Originally Posted by darthvader View Post
    typically we insulate at the damper throat where the vent liners pass through. if the masonry fireplace is built properly you don't need insulation around the insert.

  6. #6
    Join Date
    Dec 2011
    Location
    PA
    Posts
    206
    use ceramic blanket insulation, you are not allowed to use standard fiberglass insulation. If you don't have access to ceramic insulation, and don't want to buy it, it is not required to use it at all.

  7. #7
    Join Date
    Aug 2004
    Location
    S.E. Pa
    Posts
    6,294

    Question references on that prohibition

    Vader, do you have a reference for fiberglass blanket not being allowed to pack a damper area on a gas DV insert?

    You don't have the make and model of this fireplace so the only other reference would be the code, which points you to the listed instructions.

    What are the minimum specifications for an approved blanket packing? Can mineral fiber such as "Rockwool" or "Roxul" brand mineral fiber be used? What density? Is there a standard on how tightly it must be packed for air tightness? Moisture permeability? VOC content? R value or K factor? Can I make a sheetmetal panel tightly fitted around the liners instead? If so, can I caulk between the sheetmetal and liner and if so, what specified caulk?

    If the throat is not sealed, they will in all likelihood suffer from cold air infiltration. This also would be a violation of most current energy codes.

    Just wanted to caution you on such strong absolute terms spoken with authority.

    To orcking, I advise you to check out www.nficertified.org for a list of certified professionals in your area. Not a guarantee of quality or performance but a good place to start.

  8. #8
    Join Date
    Dec 2011
    Location
    PA
    Posts
    206
    You are correct Hearthman, there is no source that states you can't use fiberglass insulation specifically. All of the install manuals for our inserts state use "non-combustible insulation" which would obviously exclude faced insulation, however the use of non faced fiberglass would be allowed as long as it passes the ASTM E 136 test, which i assume would be all major brands? I never knew non faced fiberglass insulation was classified as non-combustible

  9. #9
    Join Date
    Aug 2004
    Location
    S.E. Pa
    Posts
    6,294

    Cool

    My point was to point the inquiry back to the listed instructions rather than generic information or heresay. I have read manuals stating to stuff "fiberglass insulation" in the throat. They didn't even say to use unfaced batts. There was no specification for "non-combustible" in some manuals. Sure, ASTM E-136 is the recognized test std. for what constitutes "non-combustible" but the instructions must specify one term or the other. That's all.

  10. #10
    Join Date
    Jan 2011
    Posts
    42
    Thanks for both inputs..
    some nficertified contractors said they put fiberglass around the damper and some say if you seal the cap vent properly then no need for insulation.

    Its really hard to find a good quality contractor.

  11. #11
    Join Date
    Dec 2011
    Location
    PA
    Posts
    206
    Quote Originally Posted by orcking View Post
    Thanks for both inputs..
    some nficertified contractors said they put fiberglass around the damper and some say if you seal the cap vent properly then no need for insulation.

    Its really hard to find a good quality contractor.
    do both for best results

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