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  1. #1
    I have a question about my fireplace. I took down all the wallboard around my fireplce because it had gotten wet many times before the leaking roof was repaired. When I started to remove the wallboard directly above the firebox I noticed that there is no insulation whatsoever. My question is this, can I put insulation in this very large cavity? In the winter I could feel cold air entering the house from this area. The fireplace is ducted and I don't believe it is the double duct kind- exhausts and intakes with the same pipe- Any help will be appreciated.

  2. #2
    Join Date
    May 2005
    Madison, WI
    Every fireplace can have different clearance requirements, as well as each brand of venting.

    You want the fireplace to be inside the envelope of the house so it would be a very good idea to insulate and drywall (or thermoply) the outside walls of the chase. When doing this make sure all combustible clearances are maintiained. In no circumstances do you want insulation touching the fireplace or the vent. Some venting and fireplaces I have seen can have as much as 3" or more clearance requirements.

  3. #3
    Join Date
    Aug 2004
    S.E. Pa

    Exclamation ditto JTP, as usual

    Stated clearances are air spaces and cannot be filled with anything, whether combustible or not. The problem with insulation is, it works! Great for starting fires where packed around hot things like fireplaces, chimneys, gas vents, etc. unit and venting must be installed to the mfrs. listed instructions or not at all.

    Bring the Fp into the home by weatherizing the chase:
    caulk, foam, and seal air gaps, insulate, then sheath with Thermoply and foil tape if your local code nazi allows it. Best overall performer and Tply is a lousy food for mold unlike drywall. For above the Fp, make a sheetmetal pan, then R-30 unfaced batt up to a firestop insulation shield.

    JTP knows what he's talking about. -Has the heat up there just made your mosquitoes grow bigger and juicier? ;-)


  4. #4
    Thanks for the input.

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