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insert block off questions before i attemp to put one in

Post in 'The Hearth Room - Wood Stoves and Fireplaces' started by tumm21, Jul 28, 2013.

  1. tumm21

    tumm21 Member

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    I have a regency medium insert that I have been using for about 6 years now. It currently does not have a block off plate above it right now but am going to install one but would like to ask some questions first. First off is 26 gauge steel ok and how much rock wool insulation should I stuff in the damper area. My chimney is in the middle of the house so its an interior chimney. Also how much of a difference will me doing this make as far as the amount of heat I will get after I do this. In your opinion is it really worth doing this on an interior chimney. I can tell you I do feel the walls get warm above the insert on the second floor. So I must be loosing some heat but is this really worth the work and material. Also does anyone have any rock wool they dont need. I am in North Jersey. Thanks All.

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  2. Don2222

    Don2222 Minister of Fire

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    Hello
    The rock wool (Roxul Brand) insulation is great stuff! It keeps your precious room heat from going up the chimney and it is 100 percent Fire Proof! I bought a bag of R23 sheets a few years ago. It is a bit pricey but Am getting my money back now!
  3. begreen

    begreen Mooderator Staff Member

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    Pack the Roxul fairly tightly, but not enough to dent the liner. 26 ga is fine for the block off plate. It's easy to work with. That said, I would probably skip the plate and just use the Roxul on an interior chimney. A more dramatic effect is usually seen with exterior chimneys. You will still feel some warmth on the upper parts of the chimney. We did in spite of packing around the liner. The liner still will be carrying 4-600F flue gases on a regular basis. Some of that heat gets radiated to the chimney walls.
    Woody Stover likes this.
  4. Stax

    Stax Minister of Fire

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  5. tumm21

    tumm21 Member

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    So I should not bother with the metal block off? Just stuff insulation? WillI get the same efficiency? If so it would be alot quicker and easy.
  6. begreen

    begreen Mooderator Staff Member

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    What got you thinking about this in the first place? Is the stove not heating the house well?
  7. tumm21

    tumm21 Member

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    No its ok just dont know if there is more II can do to keep the stove hotter longer for overnite burns.
  8. begreen

    begreen Mooderator Staff Member

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    I don't think a block-off plate will help achieve that. Short of having more capacity, burning locust, osage orange, white oak at night may be the best bet. How tall is the liner on the stove? How do you load it (E/W or N/S)?
  9. tumm21

    tumm21 Member

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    liner is 25 ft and I load east west most times But will I get more heat out of the stove with the block off
  10. KaptJaq

    KaptJaq Minister of Fire

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    How well sealed is the top of your chimney? Is hot house air able to escape at the top?

    I have a similar setup, an insert on an internal masonry fireplace/chimney. I used stainless bailing wire to hang a small cage at the ceiling level and around the liner. This stops the rock wool from settling further down and towards the stove. I used a long pole to stuff rock wool/roxul down from the top to fill the gap around the liner above the ceiling/heated part of the house. I then bent the stainless top plate to fit snugly over the top of the tile liner, sealed it with a lot of silicone, and tightened it with over-sized worm clamps.

    The masonry chimney in the living area warms nicely and radiates a gentle heat in all the rooms it passes through.

    KaptJaq
  11. Tom Wallace

    Tom Wallace Member

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    I don't mean to hijack the thread, but I have related question. Is it advisable to add some roxul just below the chimney cap, around the liner? Does it make any difference? I imagine it would help keep some heat inside the chimney, radiating heat into the bricks. In my case, a little over half the chimney is above the living space anyway, so it may not make any difference.
  12. begreen

    begreen Mooderator Staff Member

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    Some, but not as much as when there is an exterior chimney.
  13. Nick Mystic

    Nick Mystic Minister of Fire

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    When I installed my Jotul F600 this past February I installed a block off plate inside the fireplace and laid insulation on top of it to help hold a bit more heat and to muffle any noise the metal plate might make while heating and cooling. My massive brick chimney is located in the middle of my house, so I wanted some heat to reach the thermal mass for slow heating over an extended time. That's why I did not insulate the entire liner. However, I did pack my tile flue with insulation for the top several feet where the chimney is above the roof line. I also sealed the top plate with a thick bead of silicone caulk to keep any heat inside the chimney from escaping. I wanted to keep my SS liner as warm as possible up top to minimize any creosote build up. This approach seemed to work well since I was getting some impressive IR readings off my inside chimney and my liner had very little creosote up top when I recently cleaned it.
  14. KaptJaq

    KaptJaq Minister of Fire

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    As mentioned above, this is what works best for me:
    If you have questions specific to your install you can always start a new thread...

    KaptJaq

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