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Durock installation tips.

Post in 'The Hearth Room - Wood Stoves and Fireplaces' started by Rickb, Apr 9, 2013.

  1. Rickb

    Rickb Minister of Fire

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    So the chimney is installed and its time to get the cement board up. The guy is coming next week to do all my drywall work and I would love to have the cement board up before hand.

    Anyone have any tips or tricks to cutting/installing it?

    Also for the hearth anyone have any recommendations for screw spacing and 1 layer or 2? Also did you glue it down or just screw?

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  2. bag of hammers

    bag of hammers Minister of Fire

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    I'm not sure what your layout is. Perhaps a bit more detail about your install (stove, model, etc.) would be helpful for others here to understand what you're trying to accomplish..?

    In general, I use an old skil saw with masonry blade to cut durock (incredibly dusty - wear a mask and cut it outside). You can also score and snap it but the saw / blade makes a nice clean edge and it cuts like butter. There are special screws you can get at the box store for fastening durock or other similar products - this may be more of a concern for projects like wet areas (screws won't rust) but they have more bite and wider head than standard construction screws, or drywall screws. May not be as much of a worry for a hearth project, but I like to use them.

    My hearth is 1 layer 3/4" plywood, durock glued (PL Premium) and screwed over that, a layer of Ditra (left over from bathroom project) and thinset / tile over that. Been solid now for just over 3 years. I imagine your hearth may be built differently to satisfy your stove requirements (R-value, etc.) and other considerations, so YMMV. Hope this helps somewhat. Good luck with the project....
  3. begreen

    begreen Mooderator Staff Member

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    I have used score and snap with Durock. Do it over a sharp edge and it breaks cleanly. Follow the mfg. directions for screwing. I think the spacing is every 8".
  4. BobUrban

    BobUrban Minister of Fire

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    I use an angle grinder with a cutting wheel and x2 on outside, preferably a windy day and stand up wind. A dust mask is required as well.
    ScotO likes this.
  5. bag of hammers

    bag of hammers Minister of Fire

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    I've heard others also say the same thing - I don't have much luck with it (and I have lots of outdoor space with no neighbors to choke out on the dust) so I just run the saw over it. I haven't used the newer Durock (next gen?) so maybe that's a bit better to work with?

    The saw was also a great way to make a couple of small "plunge" cuts in the center of the durock layer to accommodate an OAK connector under the pedestal.

    On the flip side, if the edges are not going to be exposed or an issue (e.g. the durock is buried under other layers, trimmed out, etc.) then a super clean edge isn't such a big deal so score and snap would prevent some dusty mess.
  6. BobUrban

    BobUrban Minister of Fire

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    Next Gen may be better at something but that "something" is not making less dust!!
  7. begreen

    begreen Mooderator Staff Member

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    Score it, snap it no dust at all. Here's how to do it, snap cut instruction starts at 1:00.

  8. DAKSY

    DAKSY Patriot Guard Rider Staff Member

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    Last time i worked with it was for a substrate for tile shower walls & seeing as the wet saw was on location already, I used that & I'll tell ya, beeeyootifully clean cuts & minimal airborne particulates...
    ScotO likes this.
  9. jdp1152

    jdp1152 Minister of Fire

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    Pick up one of those cheapie grout remover tools at Home Depot. Use that to score it. Works great and minimal mess
  10. bag of hammers

    bag of hammers Minister of Fire

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    Could be the tool I was using to score it wasn't great - or just that, in my never ending list of projects, I'm learning that there are some things I'm pretty good at, and some things I suck at (even some simple things). This might be the case here.
  11. bag of hammers

    bag of hammers Minister of Fire

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    A couple pieces of durock used for a heat shield on my old stove looked much nicer with the smooth saw cut (a couple of exposed edges there). Scoring is a clean cut, but not "smooth" which is nice to have in certain cases. Just stirring the pot some more ;).

    Bob - the wet saw would be nice. I have to agree that the dust is crazy, this is not an indoor job (if using a skilsaw) - or outdoors either, if you're anywhere near / upwind of anyone who might not appreciate it. And silica dust is not something you want a lung full of.

    Did I just talk myself out of the skilsaw? lol...
  12. Rickb

    Rickb Minister of Fire

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    Great suggestions so far thanks everyone. I think the new next gen stuff is easier to score/snap then the older stuff. Will be trying to do it this weekend. Will post pics of how it works out.
  13. Cynnergy

    Cynnergy Feeling the Heat

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    We just scored and snapped our Durock NextGen last weekend using an X-acto (sp?) knife. Worked great. The edges were a bit rough, but we rasped them smooth easily with minimal dust.
  14. ScotO

    ScotO Guest

    score-snap works fine on straight cuts, doing curves or angles it gets a little trickier. I use my 4" angle grinder with a dry masonry bit and a dust mask. Do it outside, as was recommended, and it'll be a breeze.

    Also, I would shy away from adhesives. Keep in mind if your durock is in an area where clearances are in question, most adhesives are considered combustibles......
  15. bag of hammers

    bag of hammers Minister of Fire

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    Never even thought about that. I glued and screwed the durock (probably overkill - not like it's gonna walk away under @ 500 lb of stove and tile). But my stove only needs ember protection, so I'm not sweating it too much. But otherwise something to consider.
  16. ScotO

    ScotO Guest

    I think you'd be fine with ember protection, but if it was for a surround with close clearances, I'd shy away from using adhesive....
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  17. ScotO

    ScotO Guest

    I'm getting ready to install the Durock on my floor in the living room entryway as I type this. Hoping to do it this evening. I always put a scratchcoat of mortar directly on the floor, use the notched trowel on it, then lay the Durock right over top of that and screw it down. When the mortar underneath the cement board dries, it fills the voids and low spots under the durock, helping your tile stay stable.....

    Nothing wrong with a little 'overkill'.....::-)
  18. TheBean

    TheBean Member

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    +1 on staying away from adhesives. Best to use thinset between layers and over the initial subfloor. It helps to moisten plywood or OSB just a touch before laying out the thinset otherwise the thinset could set up too quickly and compromise the bond. Cut or score & snap- always best to do either outside.
    bag of hammers and ScotO like this.
  19. bag of hammers

    bag of hammers Minister of Fire

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    Guys thanks for the insight on the adhesive use.
  20. Rickb

    Rickb Minister of Fire

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    So for the base I have 2x6's on 8 inch centers with 3/4 plywood over it. Then I will do a scratch coat of thin set with like a 1/4" notch trowl with 1 layer of 1/2" durock?

    Then I will be doing something on top of it. I haven't decided on what yet. (Tile, maybe some thin flagstone things, something else.....)
  21. TheBean

    TheBean Member

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    Confirm the required "R" value for the unit you are installing. You may need an additional layer of durock. Used to have a worn down 1/4" trowel for the initial scratch coat.

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