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Finally got around to insulating my fireplace

Post in 'The Hearth Room - Wood Stoves and Fireplaces' started by mellow, Nov 13, 2011.

  1. mellow

    mellow Resident Stove Connoisseur

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    Been able to run for a few days straight with the cold temps, I really do not see that much difference in everyday operating, where I see the difference is in how much longer the fan stays on because the insert stays warm longer and I now have large coals in the morning after an overnight burn to get the stove going again, before I would just have a few small coals and it would take more effort to get the fire started.

    So far it was well worth the $40 for the Roxul and the time to install it.

    The insert runs as normal with peaks to 550-575 top plate temp. then back down, the added insulation does not make the insert over fire.

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  2. BKInsert

    BKInsert Member

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    Thank you for the update! Sounds like it was well worth it. I just insulated the attic above the den where the stove is at, put 8x R30 (9") rolles for a total of 200 feet. I only had 6" insulation before, I hope this will help with retaining the heat in the house longer.

    Did you paint the insulation?
  3. mellow

    mellow Resident Stove Connoisseur

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    Nope, if there are fibers that drop the surround will block them from coming into the living area. The secondary air intakes feed the fire box so no fibers would get into the house.
  4. Ram 1500 with an axe...

    Ram 1500 with an axe... Minister of Fire

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    Could the bigger coals be from using a different type of firewood? Thanks....
  5. mellow

    mellow Resident Stove Connoisseur

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    It was the same type wood back then, I burn a lot of Maple and Gum. This was posted back when I had my XTD insert, I now have a larger catalytic insert.

    Needless to say the Roxul helps a lot to keep the heat in the fireplace which translates to longer burn times, also helps to have an insert that will have meaningful heat for 12 hours per load.
  6. resonator

    resonator New Member

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    Hello. So you just lined your fireplace with Roxul, it comes in contact with the insert on the sides but not the top? Any problems since you did this? Do you see any problems if the Roxul comes in contact with the top of the insert?

    I've had an insert for a couple of years (Drolet 1800, bought used, some cracked bricks but works great) but like you, I'd been putting off the insulation part but there's a serious draft. I'm getting around to it now, and I happen to have Roxul soundproofing (denser than the thermal insulation but they don't report an R-value). Your post is the most relevant thing I've found. Thanks for posting those pics.
  7. BrotherBart

    BrotherBart Hearth.com LLC Mid-Atlantic Division Staff Member

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    Last edited: Nov 20, 2013
    tfdchief likes this.
  8. BrotherBart

    BrotherBart Hearth.com LLC Mid-Atlantic Division Staff Member

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    Something I have to ask. If there is a draft around that insert it means air is going up that chimney somehow. Do you have a chimney liner and is there a top plate up top that is sealed?
  9. mellow

    mellow Resident Stove Connoisseur

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    Drolet (sbi) is fine with using roxul up against the insert, but do me a favor and start a separate thread with your issue.
  10. mellow

    mellow Resident Stove Connoisseur

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    Ok sooo.. I was outside the other day and just happened to put my hand on the outside brick of my fireplace, it was warm, so I went out today with it being in the upper 30's and according to the IR gun my outside brick right up the middle where my insert sits was at 60 degrees.

    Roxul alone is not cutting it for keeping the heat in the fireplace.

    Im up in the air with pulling the Roxul and putting in Durock around the sides and back and making a block off plate out of cement board as well and then putting Roxul on top or behind that. Durock will be lighter so If I make some metal support beams to hold it up and drill a hole for the liner just to try something different, most of you guys are using metal.

    Got a break in the weather on Saturday so might let the insert go out then pull it out (fun!) to get this done.
  11. mellow

    mellow Resident Stove Connoisseur

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    Updated my insulated fireplace, went with Durock for Back and block off plate with Roxul behind and on top of that for extra insulation. Pictures can be found here: Got the itch again... Jotul C450 Kennebec
  12. warm kitty

    warm kitty New Member

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    Thank you for your post. I was concerned about the insulation in direct contact with the stove. I have always burned a Consolidated Dutch West small Federal (free standing). In our new home we have an old Appalachian wood insert, which is all very new to me. Our fireplace was a steel prefab. In order to get the insert in, we had to plasma cut the damper and back out of the firebox. Of course leaving a gapping hole. I know we are losing a ton of heat up the chimney. On the first nice day, (it's 0 outside) I WILL be installing the Durock and the Roxul. I am confident this will make our stove more efficient.
  13. mellow

    mellow Resident Stove Connoisseur

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    Since the Durock+Roxul is doing such a good job on blocking the heat on the back and top I will be lining the sides of my fireplace with it as well this weekend. I will be anchoring it to the steel fireplace box.

    [​IMG]
  14. mellow

    mellow Resident Stove Connoisseur

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    After seeing the gains from just the back piece of cement board I have gone ahead and done it properly on back,side,bottom,top.

    Just about finished:
    insulated fireplace 1.jpg

    Finished and painted with high temp black paint in case I decide to run with no surround:

    insulated fireplace 2.jpg


    Will let you guys know how it does.
    ddddddden, warm kitty and Jags like this.
  15. warm kitty

    warm kitty New Member

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    Did you go with just the Durock? I'm not seeing the Roxul. I'm keeping close tabs on your project : )
  16. mellow

    mellow Resident Stove Connoisseur

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    Roxul is behind the Durock on the back, no Roxul on the sides as I do not have the room. Also have a block off plate made from Durock on the top with Roxul on top of that.
  17. ozibit juice

    ozibit juice New Member

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    have you fired it up yet? noticeable burn time difference then before?

    it looks amazing man good work!
  18. mellow

    mellow Resident Stove Connoisseur

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    got the Appalachian reinstalled yesterday, checked the exact spot on the brick outside after running the insert for 12 hours and I was pleased to see that it was at 50 degrees. With the 30 degree elbow I just installed the liner is closer to the brick where I measure above the block off plate, guessing I would have seen lower temps without the elbow.

    It is still to early to report on overall performance gains, but it does seem to be holding temps longer.
  19. mellow

    mellow Resident Stove Connoisseur

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    Loaded the insert last night at 9pm, came down this morning at 8am to the cats still purring along at 1000 degrees and the downstairs at 73, had a low of 25 overnight so I think it is safe to say the updated insulated fireplace with Roxul and cement board IS helping to keep the heat in the firebox resulting in even longer burns.

    My block off plate is half inch Durock with a layer of Roxul on top of that. The side cement boards do not have Roxul behind them, the back has Durock and Roxul behind it. The insert does sit on top of half inch cement board now.

    The addition of cement boards also helps to block out the fibers from the Roxul as a bonus.

    My next upgrade will be when I redo my hearth I will get some sheets of Micore, I will upgrade the Durock to Micore for better R value.
  20. mellow

    mellow Resident Stove Connoisseur

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    Just wanted to do an update with the temps in the teens and windchill in the negatives I can see a big difference between Roxul only and Roxul + Durock, the Appalachian was a pain to get hot enough to heat the room in windy freezing temps, now it is keeping up, when I went home for lunch it was 71 degrees with the cat purring at 1500. No other changes have been made, just the addition of Durock.
  21. jatoxico

    jatoxico Minister of Fire

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    Mellow how is the Durock holding up? Get different info on it. When installed it will prob almost touch the side of the insert in a few spots. Any issues in your estimation?

    My installer is coming Monday and while he has the stove out I am going to add more Roxul in the damper and 24 ga metal block off. Want to line the box w/ Durock and hopefully, like your install I will have room for some Roxul in the back. Prob not on the sides.
  22. mellow

    mellow Resident Stove Connoisseur

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    Mine touches the Durock in the back, it is concrete board it will take quite a bit of abuse and heat. I will have to be more careful with the Micore as it is more fragile.

    No Roxul on the sides I don't believe is a deal breaker due to the heat going to the brick inside the house, the back is what you really want to insulate that heat loss against. I would still suggest Durock/Micore on the sides to help reflect some of that heat back to the firebox, I do believe it has helped but I can't quantify it like I can the back. And by quantify the back I mean stop all heat loss by measuring the bricks on the outside and seeing no temperature differences.
    jatoxico likes this.
  23. Nelson

    Nelson New Member

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    Interesting idea. I have a similar set up with an exterior masonry fireplace, in which I have a small insert at the moment (looking to upgrade in the fall).

    How did you go about attaching the durock/roxul to the back of the fireplace?
  24. mellow

    mellow Resident Stove Connoisseur

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    It was all tight fitting, the only place I needed to attach it to the wall was the back top, I used some 2" metal sheet screws with washers so it didn't crack the durock.
  25. Nelson

    Nelson New Member

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    Cool, thanks!

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