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Flue liner insulation.

Post in 'The Hearth Room - Wood Stoves and Fireplaces' started by Marty, Aug 21, 2006.

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  1. Marty

    Marty Feeling the Heat

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    I am still waiting to hear back from my dealer on this question so I thought 'why not get a second opinion first'?

    They are telling me a combination of vermiculite fill with a few alternating layers of morter is a good option that they often use. But to fill a glass it needs a bottom, I dont understand what goes under the vermiculite to prevent it from just filling the house!

    What product would be good to stuff down in to form a base layer that would hold the vermiculite or similar product and where can I get it?

    My Clay flue is 16"x16" and the liner is 6".
    My chimney has no bends... when you look down from the top you see the floor of the firebox.

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  2. MountainStoveGuy

    MountainStoveGuy Minister of Fire

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    They should install a block off plate around the damper, the liner will pass throught the block off plate, and the plate will hold the insulation.
  3. heydan

    heydan New Member

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    My dealer installed a flexible stainless steel liner into my chimney with no insulation at all. Am I losing something by not having insulation?

    My chimney is in the interior of the house and it already had some kind of liner over the brick (tile or clay or something). I was not required to use a stainless steel liner but I did anyway.
  4. MountainStoveGuy

    MountainStoveGuy Minister of Fire

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    Its not 100% needed in every application, but it never hurts to have one. You did the right thing by installing the liner, it will draft better then a direct connect 8x8 flue, and it will be much easier to clean. Insulated liners draft even better. It cost almost twice as much to have a unlined flue cleaned because they have to pull the insert.
  5. elkimmeg

    elkimmeg Guest

    The block offf plate should be part of any fireplace installation. I'm puzzled about filling that large of liner with Vermiculite. That's cheaper than an insulation wrap?. Something does not sound right here? Using motar then vermiculite is cheaper or better? To fill that large cavity???

    The person giving you this advice would't have a last name of Howard, Fine, or Howard would they?
  6. MountainStoveGuy

    MountainStoveGuy Minister of Fire

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    I dont know what the price difference is, but they do offer pourable insulation throug sweep supplies. Every installer has there own way of doing things, and my guess is this guy likes the pourable stuff. Probably easier to install? But your right, thats a huge chimney to fill.
  7. Marty

    Marty Feeling the Heat

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    Even bigger than that...
    16" x16" is only the first 10' down from the top then it widens as it descends 7' more to the top of the damper.

    No one in particular giving out the advice so much as me soliciting it from them.

    Today I removed my giant stone cap and swept about 2 gallons of ash off the walls.

    I am progressing toward installing her myself so I have to beg borrow and read whats not in the manual.

    i will try and get som pics up so you guys can get a better idea of what I am dealing with here.

    Thanks.
  8. Marty

    Marty Feeling the Heat

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    This shot is from about even with the damper.

    Attached Files:

  9. BrotherBart

    BrotherBart Hearth.com LLC Mid-Atlantic Division Staff Member

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    Wow! A chimney Santa could actually climb down.
  10. skypager

    skypager New Member

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    Will definetly need to have some sort of insulation in there. I'm sure that's one cold chimney and it doesn't have a clay liner. I would use the wrap. Definetly not a problem fitting a wrapped liner down it. The quantity of vermiculite to fill that chimney will be enormous and I don't see any advantage of doing so.
  11. Marty

    Marty Feeling the Heat

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    The top 10' (which is outside chimney) is clay lined.

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  12. webbie

    webbie Seasoned Moderator Staff Member

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    I don't like that idea.

    I did it once, and the stuff found a TINY hole and all leaked out like sand.

    Wrap the pipe - or use a 100% poured liner with bladder.
  13. Marty

    Marty Feeling the Heat

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    Well the dealer just called me back.

    He says he could sell me a blanket but doesn't think it's necessary.

    He says the way they do it is to pack 'yellow' high temp insulation up around the liner from the bottom and down around the liner from the top.

    What do you guys think about useing both methods...
    Wrap the liner in a blanket where it is an outside fireplace, then sorround it with this high temp yellow insulation of his at the top and bottom and install a blockoff plate on either end.

    I want to do this right but wouldn't mind saving a few bucks if there is a good safe way to do it cheaply.
  14. BrotherBart

    BrotherBart Hearth.com LLC Mid-Atlantic Division Staff Member

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    As short as that chimney is I would wrap it top to bottom, do the filling with insulation thing at the top and the bottom and a bottom block off plate with a top sealing plate.

    A draft issue as much as a safety issue. Of course I am not a stove expert. Just an old wood burning nut but I would want to coax as much draft out of that seventeen feet as I could get.
  15. Marty

    Marty Feeling the Heat

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    by the way here's a pic of the dead old stone chimney cap...

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  16. webbie

    webbie Seasoned Moderator Staff Member

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    I don't know! That yellow stuff sounds like it might be regular fiberglass and might be used instead of a proper metal sealing pan at the bottom.

    A 6" pipe which was spaced so that it ws somewhere in the middle of that large chimney should be extremely safe - but insulation would help it warm up faster. Just make certain they use a tight fitting metal seal at the bottom. That "yellow stuff" sounds hokey.....

    Stuffing insulation at top and bottom is not needed whether or not you insulate pipe. If you really want to go overboard, glue some insulation to the top of the damper sealing plate - but this is not needed either.

    If you need to get more height (you didn't tell us what stove or where you are located - climate), then you can install one of my little extendaflue castings up there and run the stainless liner up through it.

    http://www.extendaflue.com
  17. BrotherBart

    BrotherBart Hearth.com LLC Mid-Atlantic Division Staff Member

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    BTW Marty, how many flues are in that chimney? It looks like at least a two holer.
  18. Marty

    Marty Feeling the Heat

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    That all sounds like good advice Craig and BB.

    I'm in Pittsburgh PA and am swinging towards a Mansfield.

    The chimney seems to have a nice draft as it's currently configured even today it was blowing some dust in my eye as I worked up top.

    What kind of spacer products or devices are available maybe this is missing piece of the puzzle that I'm not seeing.
  19. webbie

    webbie Seasoned Moderator Staff Member

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    Make 'em up on the job....

    Like a piece of metal with a 6" hole in it and then bend the ends up 1" around the 4 sides....make it fit loosely so it can easily slide down the stack.....might be harder with flex than rigid.

    Another option...would be small 90 degree angles made of sheet metal or ss that held pipe like an X. See drawing.

    One option shows a round spacer - this would work also...something like a large storm collar or trim ring.

    If pipe is held centered at top, you may only need one of these...especially with rigid. But it will help to keep the pipe straight, also help when cleaning so that pipe stays stable, etc.

    If you cannot fond something suitable local, PM me and I can make it in my shop - I have ss sitting around as well as a circle shear. Galvanized should work for this application also....paint it and it will last even longer (RED PRIMER).

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  20. suematteva

    suematteva New Member

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    BB is right on about the insulation on the draft issue...ours is in that ballpark (can measure this weekend if necessary), we have a 7" ss pre fab chimney running inside the house...when it is in the 50's humid outside, and all is cold stove and pipe(mostly spring and fall) , she takes some extra starting materials until the chimney gets warmed up and pulling...insulate well.
  21. Marty

    Marty Feeling the Heat

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    Good eye. Basement water heater is in the second hole, furnace exits at the front of the house through PVC.
  22. Marty

    Marty Feeling the Heat

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    So I should wrap it for 17', from the top of the block off plate to the bottom of the cap.

    Craig, those drawings make a lot of sense. How do the brackets attach to their positions on the liner... hose clamp?
  23. elkimmeg

    elkimmeg Guest

    Marty I was in Pitts last weekend saw the Cards Pirates game saturday night played golf there as well. Stayed at the Hilton right in front of the 3 rivers park.

    Back to business at hand. Your chimney and liner. You keep getting the type of advice from that dealer and I was not too far off in there description. Moe Larry and Curly. From the sounds of it you are far better off doing the work yourself.
    then letting the stooges work there.

    There is no high temp yelllow insulation wrap Instead of pink Owens corning they are using common fiberglass John Mansville yellow.
    What a BS line that one is.

    This is the right and correct way to do that job. Bottom sealed metal dasmper block off plate. Decent quality and brand ss 304 flex liner Wrapped with the proper insulation and outer mesh. At least on or two center spacers and galvanised Alumium or Stainless steel chinmey cap cover ant the proper termination cap RTV caulk, a gererous amount.where the liner penetrates the cap to seal out the weather Refactory cement sealing the liner t opening in the damper plate area. . Craig got it right I'm just emphasising what he said .
    Don't get talked out of not needing a metal damper plate for some common fiberglass . The common fiberglass approach is usually employed by stooges. The stooges humor is not directed at you Marty but to the source of the bad suggestions
  24. BrotherBart

    BrotherBart Hearth.com LLC Mid-Atlantic Division Staff Member

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    At the risk of incurring the ire of the webmaster, putting those things on that insulated pipe and then getting it down the chimney would be a nightmare. Your dealer is going to think so too and make ya pay dearly for it.

    Heck wrapped solid pipe with a plate top and bottom on that chimney isn't going to be touching the sides, spacers or no spacers. The only reason I can see for a flex liner is that you can wrap it all at once and then feed it down the flue. Can't do that with seventeen feet of straight solid pipe. You have to connect each section and wrap it one section at a time going in. That could be the deal killer for solid on this one. On any top down install for that matter.

    But even with flex, no longer than that run is a tug at the top and the bottom is going to straighten the sucker out enough that the plates will keep it away from the chimney walls.

    <ducking under the desk again>
  25. elkimmeg

    elkimmeg Guest

    If you read you furnace manual they will tell you instructions for proper hotwater heater venting without the burner assistance of heating the flue What chance do you think a 3" vent has drafting a in that flue or chase.. The furnace manual will detail the folly of your installation It is the responsibility of the furnace replacement installers to make your gas hot water heater draft compliant. It isn't plain and simple cross sectional codes applied. It requires its own separate 3 or 4" liner a chimney cap and proper termination cap
    Another way but not legal in an un lined chimney is a draft inducer. There is a good chance that draft hood in emitting carbon monoxides. Don't believe me read the burner installation manual
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