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Community and Q&A

Durock in lieu of Sheetrock

askeena7 | Posted in General Questions on

Hi all,

I’m wondering if Durock can be used instead of Sheetrock? Many of the exterior walls will have wood paneling on top of said Durock. Is Durock an acceptable alternative to Sheetrock if it’s seams are taped and plaster venner skimmed? I can’t seem to find any info on if it is airtight/ what its vapor perm is. The reason I am considering Durock instead of Sheetrock is the structure is in the hot humid flood prone south where moisture and mold is a big factor. 

Any insight would be great!

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Replies

  1. ohioandy | | #1

    Durock is a great product, but I'm not sure it makes sense for areas larger than a bathroom or kitchen backsplash. The 1/2" version comes in 3'x5' sheets, which isn't convenient for standard stud spacing, and there's no taper on the edge for mudding. It's just another gypsum variant; but more expensive than the various other drywall products intended for high-humidity and room-size applications.

    EDIT: Subsequent comments make me realize I mixed up my brand names. I was thinking of Fiberock, which is a USG gypsum tile backer. You referred specifically to Durock, which is most certainly a cement board. FWIW, I have never found a use for true cement board that can't be served with a more user-friendly material.

    1. Expert Member
      MALCOLM TAYLOR | | #2

      I agree I wouldn't use Durock (but it is cement based, not gypsum). Maybe something like DensArmor?

  2. askeena7 | | #3

    Yes! I am definitely interested in that paperless drywall. Seems like the best bet as it would be easier to work with and still pretty good in humid climates. For walls under the wood wall covering I assume I could just tape and mud the seams and focus on air tightness?

    Thanks for the insights.

  3. walta100 | | #4

    So when the flood happens what is the plan?

    It seems to me the inside of the walls will be stinking rotting mess unless you tear it all off so it can dry.

    If I remember correctly the cost per sqf was 3 to 4 times the cost of drywall.

    I say put the house up on stilts above the record flood line.

    Walta

  4. Expert Member
    AKOS TOTH | | #5

    I've used densglass for areas that might see liquid water. It doesn't have tapered edges but you can mud and tape as regular drywall. Needs a skim coat of mud if you want it smooth to paint. It is much more than drywall though.

  5. Expert Member
    BILL WICHERS | | #6

    +1 for Densglass over durock. Densglass is a glass mat reinforced gypsum board commonly used for things like exterior facades and the like. Lots lighter than durock which is a cement board. Either one needs a skim coat prior to painting (they have a texture a bit like window screen otherwise), so labor is about the same — but Densglass is much lighter weight, more like regular drywall.

    Bill

  6. askeena7 | | #7

    Excellent. Can the densglass be left unfinished with seams taped and mudded if under wood paneling? Anybody have specs on its vapor perm and if it is an effective air barrier?

    1. Expert Member
      MALCOLM TAYLOR | | #9

      DensGlass is an exterior sheathing. The two drywall replacement panels Georgia-Pacific makes are DenShield and DensArmor. Taped, they are both vapour/air-barriers.

      1. Expert Member
        AKOS TOTH | | #10

        You have to be careful with some of the interior products. Since they are designed for bathroom, most are semi or non permeable. 1/2 densglass is very permeable, something like 20 perms, much better than almost any sheathing product.

  7. askeena7 | | #8

    Also good point about flood plan. Yes typically pull everything. So yes maybe cheaper route is way to go?

  8. tommay | | #11

    If your plan is to plaster, then use blueboard. The finished plaster is virtually waterproof. You can prove this by throwing water on the finished plaster and watch it bead off, especially if troweled real smooth.

    1. Expert Member
      MALCOLM TAYLOR | | #12

      Tom,

      Blueboard has a very absorbent paper finish, and the plaster used to skim-coat it is water soluble. It may initially bead water, but it absorbs moisture readily if immersed, by capillary action from nearby sources, or high humidity conditions.

      1. tommay | | #14

        That's why blueboard is designed to work with plaster. The chemical composition of the board reacts with the plaster to create heat from a mild acid when water is added to aid in the setting and bonding of the plaster. That is why you can't plaster on regular wallboard. Once set, the plaster is pretty much waterproof since it can no longer absorb water once the chemical reaction is done.
        i can give you the chemical components of each and explain the reaction if you like or you can find out the ingredients on your own and figure out the reaction process for yourself. It's actually quite simple chemistry.

  9. nickdefabrizio | | #13

    Many years ago I did my basement using Dense Armor Plus-the interior version of Dense Glass. It is essentially drywall/sheetrock faced with a thin layer of fiberglass. I also used synthetic tape. It has worked great-no evidence of mold. Of course, I also put foam board on the block walls, built walls inside the block out of steel studs and left a gap and insulated below the bottom plate with sill insulation-so the complete design contributed to reducing mold/moisture issues.

    My recollection is that these sheets are a little bit more expensive and heavier than paper faced drywall/sheetrock. Also, the surface is a rougher texture so I did end up skim coating (I would see if they make skim coats that are less moisture prone than typical mud). Otherwise it handles and goes up just like drywall. Remember it does have fiberglass strands in it so you should definitively wear a mask and gloves.

    I understand that there are other products that have no facing material-just solid panels. I am not sure how they work. There are also hardie panels....

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