Clearence question. New Hearth

Post in 'The Hearth Room - Wood Stoves and Fireplaces' started by Nimrod1911, Nov 18, 2012.

  1. Nimrod1911

    Nimrod1911
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    I'm putting in a new hearth. I haven't purchased my new stove yet. Currently I use a pre-EPA beast of a stove. Heavy steel plate.

    We built the hearth with 2x6 treated lumber (in basement on cement) covered by 3/8 wafer board (I put in several cross pieces of 2x6 for support). I have some thin backer board, I think it is 1/4 inch. I will then lay down mortar and full size bricks (2").

    How is that for R value protection?

    Also, do you guys coat your bricks with anything? Do you find they scratch easily when moving stove?
     
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  2. EatenByLimestone

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    If the stove is sitting directly on the basement slab, you do not need to build a hearth.

    If it is not sitting on the basement slab, but on a combustible surface... Once you pick the stove, you can verify that the R value is high enough. Otherwise, you can build to an R value of 3 if I remember correctly and be safe for Pre-EPA stoves.

    Here is a site listing common R values so you can decide how much you need once you figure out how much your stove requires:

    http://www.chimneysweeponline.com/horvalue.htm

    I would not use 2x6 lumber for my hearth. It burns a bit too easily. It could be used as a form for pouring concrete, but then I'd remove it.

    Matt
     
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  3. Slow1

    Slow1
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    I don't know what that comes out to exactly, but I don't think it is much over "ember protection" - Believe it or not the brick doesn't really add much R value. What stove do you plan to install? I'd really suggest figuring that out before spending all the time and effort building the hearth so you don't have to re-build, exclude desired stove, or worse rationalize yourself into using a hearth that isn't up to spec.

    My hearth is tile on top so no coatings or anything and I haven't had any scratches.. then again the stove doesn't move too often either.
     
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  4. webby3650

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    If it's on concrete, why did you build it up with wood? If you take the wood out of there and built it up out of bricks, or additional poured concrete and then cover it with bricks then no worries.
     
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  5. Nimrod1911

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    Another question. My stove will sit in an alcove. The ceiling of the alcove is about two feet by five feet. The chimney goes up into this ceiling where it connects to the inisulated pipe. Right now the ceiling is really just the floor joist and insulation. I need to put something on it that is non-combustible. My thought was to just put cement backer board on it and paint it. You can't really see this ceiling unless you bend over the stove and look up.
    What do you suggest?
     
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  6. Sprinter

    Sprinter
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    It sounds like you may be putting the cart before the horse. All stoves have differing requirements for clearances and hearths. Alcoves generally have specific requirements of their own. Some hearth pads require an insulating value, some do not (all have to be at least non-combustible of course). As mentioned above, though, the concrete floor is fine by itself, assuming that it is poured on grade. Am I right that this hearth is the one used for the old stove? If so, you may be able to just remove it unless you want a raised hearth anyway.

    Do have a specific model in mind? Welcome to the forum. The members here can help you with all the aspects of buying, installing and operating your new stove.
     
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  7. John_M

    John_M
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    Nimrod, "...The CHIMNEY goes up into this ceiling where it connects to the insulated pipe...." Did you mean to say the STOVEPIPE goes up into the ceiling where it connects to the insulated chimney?

    Is there a ceiling support box to support the total weight of the chimney?

    Many basements have a lower ceiling height than rooms in the living space of the house. Some stoves have a Required Minimum Clearance between the top of the stove and the combustible ceiling. Will that be an issue with your installation and the consideration of a raised hearth?

    If the alcove is 2'x 5', the 2' dimension might present a "Clearance to Combustibles" problem without a ceiling support box. Based on your description of the alcove, it appears to be very deep top to bottom. This enclosed alcove space will probably hold much extreme heat from the stovepipe and stove and might therefore require additional shielding. Just a "heads up" for your consideration.

    Best wishes and good luck:)
     
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