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Weight of stone too much for the wall?

Post in 'DIY and General non-hearth advice' started by cgbills, Feb 11, 2011.

  1. cgbills

    cgbills New Member

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    I have a 14 ft high vaulted ceiling. I plan to run the chimney of the stove through the highest point and directly through the peak in the ceiling. Also I plan to put natural stone mosaic up the entire height of the wall, from floor to ceiling, and it will be about 3 feet wide. The backing for the stone mosaic will be concrete board that has about an inch gap between the board and the drywall for cooling and air flow. The board will be secured to the studs and the spacers for the inch of space will be ceramic. My first question is will the concrete board be enough to support the weight of the stone mosaic all the way up the wall? My fear is that even if it is properly secured to the studs, the weight of 14 feet x 3 feet of stone mosaic (even though it is small almost pebble stone) will break the concrete board and cause the whole thing to come down. Do you think this would be a problem too if I didn’t do the air space, increased clearance to the stove and put the stone mosaic direct on the drywall? Would the weight of the stone mosaic be too much for the drywall? I have not put tile or stone mosaic all the way up a wall like this and I am worried about the weight of it and the wall being able to handle it. The attachment of the stone directly to the wall is different than say brick because the wall takes all the weight of the stone while the brick bears some of its own weight. Thoughts?

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  2. tiber

    tiber New Member

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    I skipped the spacers and went with metal studs. While they DESTROY drill bits to get them installed properly, they also give you much more support than the little spacers do.
  3. Eaglecraft

    Eaglecraft Member

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    cgbills:

    The additional dead load imposed on your floor by the new structure that you propose might be of concern. You don't say exactly what the construction of your stove hearth might be - for example if your stove will be located above a structure that has an independent concrete footing, as a typical masonry fireplace would have.

    I would take a sketch of your proposal to a structural engineer and obtain an opinion. What you are proposing has no place for error. The engineer should be able to offer an opinion about the ability of your floor and your proposed concrete board being able to support the weight of the stone mosaic all the way up the wall.

    Good luck.
  4. southbalto

    southbalto Feeling the Heat

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    All comes down to how thin the stone/mortar veneer is. If it's a 1/2" or less I don't thin it will be a problem.
  5. Lumber-Jack

    Lumber-Jack Minister of Fire

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    Do you even need that air space? Most modern stoves and double walled chimney have very close clearance requirements, unless you are have some reason you need to cram the stove and chimney real tight to the wall, or you have an older stove with wide clearance requirements it seems like a waste of time and materials to build in that extra wall with air space.
  6. jbrown56

    jbrown56 Feeling the Heat

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    I'd be worried more about the weight on the floor. If there is a basement below, you will have to build a weight bearing wall below to take the weight of the stone wall above. I would use wire lath scewed to cement board. Mastic over the wire and imbed the stone into the mastic. Grout it when finished. Have you looked into cultured stone? It looks real and is lighter.

    Jim
  7. begreen

    begreen Mooderator Staff Member

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  8. webbie

    webbie Seasoned Moderator Staff Member

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    I agree with this comment - the thing to look at is the construction of the floor underneath that area!
    If this wall, for instance, is in the center of a large span of floor joists, that is 100% different from it being above or near a foundation wall. If it is later, you are probably OK - you could probably park a car over or near a foundation wall.

    It would be relatively easy to buttress things up from below also - in any case. Most of the real weight would seem to end up on the floor....although some stress is taken off by tying things to the wall.

    When it comes to floor and wall loads, the idea is to spread them out a bit. Also, keep basic common sense in mind. If you had 10 people, each weighing 160 lbs, standing in one area of your room - that's 1600 lbs, quite a lot! Yet the floor is not going to cave in.

    Having a total weight for the end assembly might be a good start.
  9. ironpony

    ironpony Minister of Fire

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    from everything I"ve ever read on cultured (fake, veneer) stone
    as long as the wall it is being applied to is structurally sound
    the weight of the stone is not an issue
    although I am sure there are exceptions
    check the stone manufacturers website
  10. cgbills

    cgbills New Member

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    The stove will sit directly over the main floor joist that runs the length of the house and the cinderblock footer that holds up the joist in the crawl space. I do not see floor weight being an issue, there is plenty of support, but will have an engineer check it out. My main concern is the wall being able to take the stone and not bringing down the drywall. I think I will forgo the airspace because it was just there for cushion, I can meet clearance requirements without it and I am using a modern Napoleon 1450. Also I do not plan on building a brick hearth. Rather I will put down two layers of concrete board then stone mosaic, all over the joist and footer. I will look at some of the lighter weight cultured stone. Also maybe some of that glass mosaic, but like the look of stone.
  11. dvellone

    dvellone Feeling the Heat

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    I wouldn't veneer the drywall with stone. You need a surface that can hold the mortar and drywall isn't designed for this. The cement board is a better option and diamond lath, suggested by others, will give you as strong a stone-mortar-cement board bond that you can get.
    The load of this veneer won't be on the wall but on the floor. It's your base that you want to focus on and it's easy enough to check on the load ratings of your joists and put in a support beam and a couple pipe columns. Even if the joists can support the weight their movement and flexing could cause cracking in your veneer wall. Getting the floor good and stiff might be worth the few extra bucks and time.
  12. Eaglecraft

    Eaglecraft Member

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    cgbills:

    Your thoughts about having your proposal evaluated by an engineer is a good thing. In your case seeking the advice of a qualified professional is a wise investment. Checking out the views and opinions of others on the Internet is OK. But you wouldn't obtain medical treatment based solely from views expressed on the Internet.

    In your geographic area, you may be required to obtain an engineer's approval prior to construction. Even if your construction project does not require an engineer's stamp to obtain a building permit, you will want a professional opinion for peace of mind.

    Your project may seem somewhat trivial from an engineering point of view, but many have suffered because no one did the math. Recommended reading: How Structures Fail: Why Buildings Fall Down by Levy and Salvadort.

    Good luck with your project.
  13. dvellone

    dvellone Feeling the Heat

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    I've got to add... go with your first choice and use real stone. As long as you can support the weight it will look great!
  14. Lumber-Jack

    Lumber-Jack Minister of Fire

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    If you are not building a separate shield wall, and you have a footer directly under the wall you plan to put the stone mosaic on, then basically all you need is something solid to attach the stone to. Drywall alone won't be enough, as devellone says, "it's not designed for that", so you need to reinforce the wall. Diamond lath and a base coat of mortar is probably your cheapest option.
    Is the wall 2x6 studs? Hopefully so. If it is only 2x4 studs and a straight free standing wall, I would reinforce the wall with at least 1/2" plywood (or OSB) before putting the lath on, that would give the wall some extra stability. In any case you need to figure out how you'll finish the side edges because the lath and or plywood will stick out from the wall a bit,,,, Perhaps a rustic wood trim boarder?
  15. cgbills

    cgbills New Member

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  16. Lumber-Jack

    Lumber-Jack Minister of Fire

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    Just drywall will be fine then. :p
  17. cgbills

    cgbills New Member

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    Sorry I figured that my explanation in my first post was a little lacking, guess i should have made the back-splash comparison sooner :(


    Thanks for all the help!
  18. jimbom

    jimbom Combustion Analyzer

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    Three foot wide by 14 foot ~ 42 ft^2. If the tile is 0.25 inch thick, you will only be adding about 150 pounds to your wall. Should not be an issue. If you are close to Kentucky(ie New Madrid fault) or have experienced any of the Wabash earthquake activity, you might want to make sure your flue and stove are secure. Mild shaking is the most you might expect. USGS has maps on line: http://earthquake.usgs.gov/hazards/products/conterminous/2008/maps/ceus/ceus.2pc50.pga.jpg

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