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Green Board or Wonder Board or Both

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  • #16
    Re: Green Board or Wonder Board or Both

    DG:

    Thanks for the link, but it appears that the term: "Load bearing" refers to a vertical load applied to a flooring substrate (that makes sense), therefore a "slip sheet".
    A load bearing, bonded, waterproof membrane works well for a thin-set application over concrete slab to reduce minor shrinkage cracks from transferring up through the tile assembly and prevents moisture/dry problems of moisture wicking up through the concrete slab. Follow manufacturers directions.
    Is Michael referring to installing a slip sheet on shower walls?
    "The only communists left in the world are in American Universities."

    --Mikhail Gorbachev

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    • #17
      Re: Green Board or Wonder Board or Both

      it is load bearing BONDED ......
      within the standard is the shear,and astm c-627 (method for evaluating ceramic floor tile installations).The standard has been around since 1993 and many of the membranes have been around since the 80s..
      Dick ..You need to get out some more..by the way 4-6 mil poly or tar paper wont pass the vapor requirments of a perm rating less the 1. So they really are a moisture barrier not a vapor barrier.
      Last edited by inkster; 01-11-2007, 06:26 PM.

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      • #18
        Re: Green Board or Wonder Board or Both

        the question about using greenboard for this kind of install does not warrant a serious response, but like inkster said why would anybody consider big pieces of stone for a shower floor? I also wonder why this thread got a reply but the question about polishing granite bullnose got snubbed.

        Byrne's book on installing tiled showers is must reading if you want to know what it takes to build a good shower. To my knowledge its the only book available that contains detailed instructions on leak proof showers. I used the detail to build and tile my first shower job. Buy the book. A greenboard in shower question is not well enough researched to start a decent estimate.

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        • #19
          Re: Green Board or Wonder Board or Both

          Dick,

          We are getting hung up on semantics. I believe "slipsheet" has different meanings to different people. I just call it a "crack isolation membrane", as that is how the manufacturers refer to it and is unambiguous. Typically it is either a liquid elastomer that is painted on or a fabric that is glued on.

          Matthew,

          You forgot to mention greenboard is no longer code under IRC.

          DG

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          • #20
            Re: Green Board or Wonder Board or Both

            John Bridge has also written a couple of books on leak proof showers.

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            • #21
              Re: Green Board or Wonder Board or Both

              Jones199,
              What do you do for a living?

              You said in one post you were a software developer, and now your presenting yourself as a contractor. Which is it?

              I could be wrong, but I'm thinking your the HO.
              Rob
              O'Brien and Sons Construction
              Swansboro NC

              Comment


              • #22
                Re: Green Board or Wonder Board or Both

                Originally posted by O'BrienConstruction View Post
                Jones199,
                What do you do for a living?

                You said in one post you were a software developer, and now your presenting yourself as a contractor. Which is it?

                I could be wrong, but I'm thinking your the HO.
                I think there is more than one harry homeowner posting here.

                I havent touched greenboard for years except to pull it off the wall and get it into the dumpster . it has mold on it 90% of the time.
                work...

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                • #23
                  Re: Green Board or Wonder Board or Both

                  Originally posted by Dick Seibert View Post
                  I use Vycor (or some Bituthene like product) to waterproof behind my mortar beds
                  I would like to pick your brain a bit about your method if you do not mind. I have been following this thread with interest. You do a full mortar bed for the walls ? I guess it would be Vycor, metal lath, then mortar ? Is there a specific reason you do it this way ? (vs. CBU)

                  I use CBU and have been covering it with Redgard for a few years (prior I did the felt paper behind the CBU). I have been thinking about giving Kerdi a try mainly because I like the drain system, I presently build the pans with a liner, drain, etc. comes out good but a PITA. Basically the same type of thing as redgard, the vapor/moisture barrier on the outside of the CBU.

                  I always have several feet of Vycor lying around, I have been thinking about using that as I used to put felt against the studs, then the CBU, tape the joints with thinset, then tile. Basically this would mimic what you do with your mortar bed.

                  Do you (or anyone) have an opinion on which placement of the vapor/moisture barrier is superior and why ? I have been happy with the redgard, I used it on my own shower a few years ago and it has held up great, 2 months ago I opened the other side of the wet wall (building a closet) and the wall looked as good as the day I sealed it up. I know if I have a method that works I should stick with it but thinking about the kerdi and reading this thread had me thinking about the entire methodology.

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                  • #24
                    Re: Green Board or Wonder Board or Both

                    Some of the advantages of the Kerdi system are:
                    Consistant thickness of water/vapor barrier, no lap marks etc.
                    Tougher, more resistant to damage as you set tile and comb thinset.
                    If under board cracks, it acts as a slip sheet and canstill provide water proofing. Probably won't tear unless huge movment.
                    Drain tie in
                    No Killer fumes, just sets with standard thinset. You do have the dust when you mix the thinset though. So there are less ventilation problems and you can just wear a nuisance dust mask.
                    No Solvents needed for clean up.
                    Can use standard drywall behind so easier to cut and install than CBB
                    No need to separately tape seams of board as it is done while applying the Kerdi.

                    I like the idea of any surface applied membrane as I prefer not to allow water into the support bed, drywall, morter or CBB. Also there are no nail holes put in your water/vapor membrane.

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                    • #25
                      Re: Green Board or Wonder Board or Both

                      Thanks for the reply ... I like the points you brought up. I have been curious to give the product a try for a while now but I really don't want to use a customer's bathroom as a guinea pig. Plus since I have never worked with it I wouldn't begin to know how to price it out.

                      My G/F has been bothering me sometime about converting her half bath to a full bath. Her design is a PITA, strange shape, seat, recesses, etc. I like the idea of building everything then wrapping it in the membrane ... I think that will be my test project this spring.

                      Thanks again.

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                      • #26
                        Re: Green Board or Wonder Board or Both

                        Foxtrot,

                        Nothing wrong with Kerdi, but I don't agree with kgphoto's arguments.

                        Redgard does not need solvents. Tools clean up with water. You can dilute it, so you know it's water soluble.

                        Redgard does not evaporate with objectionable fumes or strong smell.

                        Constant thickness and lapmarks are not an issue as long as you have sufficient thickness.

                        Biggie: NO you CAN'T use drywall of any kind as tile backer in a wet area if you're under IRC, regardless of Kerdi, Redgard or any other membrane.

                        I prefer liquid membranes when there are a lot of corners and features, as Kerdi needs a lot of patching. Liquid, you just keep painting. I sure would hate wrapping Kerdi into a small niche with a middle shelf.

                        By the way, the new Laticrete liquid is approved for changes of plane without fabric reinforcement.

                        But to your original question, waterproofing is best in front of the backer. Mud beds, regular cement board and Hardi will fill with water if the barrier is behind.

                        DG

                        Comment


                        • #27
                          Re: Green Board or Wonder Board or Both

                          Originally posted by Matthew.Mobley View Post
                          Byrne's book on installing tiled showers is must reading if you want to know what it takes to build a good shower. To my knowledge its the only book available that contains detailed instructions on leak proof showers.
                          Are you referring to his book Setting Tile (C) 1995, Taunton Press, or is there another book he wrote that is specifically about showers?

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                          • #28
                            Re: Green Board or Wonder Board or Both

                            Setting Tile has very good instructions for building a mortar bed shower pan, and for the whole shower building process.

                            Comment


                            • #29
                              Re: Green Board or Wonder Board or Both

                              DG is correct! I made a mistake in lumping Redguard in with other liquid membrane products like the laticrete products. It does clean up with water and I don't know how it smells.

                              I would also agree that it is easier to paint corners, rather than line them, but I don't necessarily agree that easier is better. :-)

                              Since we are not under the IRC I am not familier with thier code issues, but I would expect there is a similar provision for installing non code approved products as long as there was information to back up their application. This is what archs and enginneers do all the time. That is why this is a prescriptive code that you can design around.

                              In the IRC, do they allow drywall behind felt and lath as a substrate to motar?

                              And let's not forget that the UBC code still allows greenboard as a substrate for tile in wet areas, and we all know that is a no no now.

                              Comment


                              • #30
                                Re: Green Board or Wonder Board or Both

                                2006 IRC:

                                Section R702.4.2
                                “Cement, fiber-cement or glass mat gypsum backers in compliance with ASTM C1288, C1325 or C1178 and installed in accordance with manufacturers’ recommendations shall be used as backers for wall tile in tub and shower areas and wall panels in shower areas.”

                                Section R702.3.8.1
                                “Water-resistant gypsum backing board [Greenboard] shall
                                not be used where there will be direct exposure to water.”

                                DG

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