Replies

1. 
   RW | Mar 10, 2003 01:10am | #1

   never heard of it. I've always used 1 layer, thinset the joints.

   " Shoot first and inquire afterwards, and if you make mistakes, I will protect you." Hermann Goering to the Prussian police, 1933.

1. 
   WorkshopJon | Mar 10, 2003 01:30am | #2

   Your way you suggest sounds a little less "backyard." Barring any other info, Ill probably do it that way. It certainly sounds easier. By the way, I like your person quote. Sure do miss C&H. My to 2 cats are named after the strip. Do you remember the one about the aliens in the "strange yellow ship that blinked as it twirled," my personal favorite.

   Thanks, Jon

1. 
   RW | Mar 10, 2003 05:14am | #4

   Gotta go with the snowmen series myself, the one with the cannonball through the gut still makes me laugh." Shoot first and inquire afterwards, and if you make mistakes, I will protect you." Hermann Goering to the Prussian police, 1933.

2. 
   Zano | Mar 10, 2003 03:21am | #3

   To stop the potential water leak between the boards I use silicon calk only.

3. 
   dieselpig | Mar 10, 2003 05:37am | #5

   Read the literature that comes with your board.  Pretty darn sure it says to use one layer of fiberglass tape made especially for cbu's and to ONLY use the thinset you plan to use on your tile.  Mixing could result in faulty bond of tile to substrate.  I just did this about a month ago and just taped and mudded the seams as I came to them.  I had no problems and a beautiful floor in my bath.

4. 
   AaronRosenthal | Mar 10, 2003 06:07am | #6

   It's not what the sheets say. Do it the way they tell you.

   I usually use glass tape and cement grout mixed like they suggest. Short working time, so do a little at a time. Smooth it in but you'll find it's gritty and not like mud or even cement.

   The reason you need the grout is because the Durock will leak through the back later when the tile grout fails and water gets in behind.

   At my age, my fingers & knees arrive at work an hour after I do.

   Aaron the Handyman
   Vancouver, Canada

5. 
   booch | Mar 10, 2003 06:23am | #7

   I don't know if anyone mentioned the issue of putting the fiberglass tape on at the same time you stick down the tile. That is supposed to make the tiles lay flatter as you adhere them later. With a big tile, 12x12, on a wall it is pretty hard to get the leverage to oomph those babies flat (coplanar) if the wall is fighting you. I guess the best advice is look over the surface with a critical eye for changes in the flatness of the durock before you add on more tape and layers.

   I just struggled thru a 2 sided shower surround in marble this weekend. When the tile get above your head there isn't much you can do to get them to lay flat except scooch it til the thinset oozes. Then you get to wipe,pick, and dig the excess from the grout joint area.

   Durock with thinset and one coat of fib tape is impenetrable. Play with it and you'll see. It is like a joint made with tightbond wood glue on parallel pieces of wood. The wood will break but not where the glue is. (in this case thinset & tape.)

   Oh yes use Modified Thinset mortar not just portland cement. Using the latex modified stuff triples the bond strength. Read a few bags and you'll see the difference in the material strength. Latex makes it tougher. Box stores and specialty stores have it in the tile area. Clean up your slops as soon as you can after 2 days it sets up REALLY Hard.

   Jack of all trades and master of none - you got a problem with that?

   
   

   ---

   Edited 3/9/2003 11:28:05 PM ET by Booch

6. 
   andybuildz | Mar 10, 2003 04:44pm | #8

   Jon

      Use liquid latex mortor additive with thinset leaving a small gap between boards.

   If its a wall in a shower area be sure to use 30# felt paper on the studs before you install the CBU as it will wick water should there be any leaks.

   If you use the suggestion that a previous poster mentioned of doing the glass tape as you do the tile be careful as you trowel not to pull it up. This could be a tricky deal. I never tried that trick myself other than in places I couldnt get to the day before I was ready to tile. Personally I wouldnt reccomend it. Just make the thinset float nice and thin and flat under the fiberglass tape and be sure to get it between the gaps in the boards

   a

   "As long as you have certain desires about how it ought to be you can't see how it is." 
   http://CLIFFORDRENOVATIONS.COM

1. 
   WorkshopJon | Mar 10, 2003 06:15pm | #9

   Andy,

   The boards are already up, and I did use 30# felt behind everything. A prior post said something about silicone caulking between the boards, any thoughts on that one? Off the topic, is that your house that pulls up in your profile? You did a nice job. I see you live in Cold Spring Harbor. My brother lives not too far from you out in Smithtown. He's got a house that has been having lots of renovations done to it (profesionally), and still many more as funds permit. I'm shocked at what they were able to get away with out there when they built in the 70's. It's about a 5500sq.ft. house, has aluminum wiring, had an underground (leaking) oil tank, saging floors, etc. In the three years he's been there I think he's dumped about $150K into correcting things (and still counting!). Wish he would have had me take a look at it before he bought it.

   Jon

1. 
   andybuildz | Mar 10, 2003 06:49pm | #10

   Jon

       The house on my website was a spec house I renovated but mostly built after ripping most of it down while I lived in the basement. It sold a few months ago but I'm still in the same town of Cold Spring Harbor.

    Bought a circa 1680 house in dier need of repair etc etc...its an historic landmark and have already had the plans approved by SPLIA (society for the preservation of Long Island Antiquities). Just waiting now for the plans to be approved bt the town of Huntington so I can start breaking ground for the additions.

   Thanks for the compliment by the way

   As far as the silicone goes on CBU's......Doesnt really make any sense to me being that the entire board is cement. I always stick with the cement product suck as thinset with additive instead of water to give it that extra stickiness and elasticity. Thats my answer!

   BE well

             Namaste

                        Andy...PS..If your brother needs any advice or work send him the link to my website (below all my posts here). I'd be happy to talk with him."As long as you have certain desires about how it ought to be you can't see how it is."  http://CLIFFORDRENOVATIONS.COM

2. 
   booch | Mar 10, 2003 09:09pm | #12

   Andy,

   The fiberglass tape is Durock brand made for the durock application. I think it is mentioned in the Taunton Tile book. You do have to be careful pressing it into the joint. I start laying/sticking it on dry then take and smear on a coat of thinset with the smooth side of the notching trowel. You do have to lighten up on the notch pressure when dragging over the joint to notch the thinset, but if the tape is set deep enough it rarely gets picked up. (1 time in 20)

   As for thinset with the latex liquid additive, There are multiple varieties of thinset available that have powdered latex additives in the mixture already. If the bag is read the yield strength gives a good indication of wether the additive is already in the mix. Polyblend or ...flex (Tec brand) are dry latexed thinsets.

   Just curious. Where does the moisture go that is trapped between the durock and the 30# felt?Jack of all trades and master of none - you got a problem with that?

1. 
   andybuildz | Mar 10, 2003 10:08pm | #13

   Just curious. Where does the moisture go that is trapped between the durock and the 30# felt?

   Booch.....I lay the bottom of my 30# felt directly onto the shower pan... and then some  (just enough to go under the CBU).... for instance on an acrylic shower pan. I naver lay the CBU directly on the pan (or tub). I lay it below the extended pan rim ("almost" to the shower pan base) just over the felt paper.

    After I lay the tile on the CBU and caulk the tile to the pan or tub (leaving about 1/4"-3/16" between the tile and shower pan)you should be leaving a weep hole in the caulking run ......in each corner. I also leave a weep hole in the center as well for the water or moisture to drain from. Never squeeze the caulk/silicone deeply into the tile or you will block the area that the water will want to flow through the weep holes.

    The rim on the tub or shower pan extends upwards a good inch or so for this purpose. The felt paper should touch the shower pan just below that rim and under the CBU.

   Also..I've never had a whole lot of luck putting down the fiberglass tape as I lay my tiles and wouldnt reccomend that to people starting out.

   I like my trowel to float/notch across the floor in a consistant pattern without having to compinsate for anything especially when I have lots of seams criss crossing each other in more complicated tile layouts.

   When I use the flat end of my trowel to get the mud down real good I push it to the CBU really hard to be sure it adheres,and that always screws up the loose tape if the notch end doesnt end up lifting it.

   Thats just me.....everyone has their own feel for things.

   Be well

            Namaste

                          andy"As long as you have certain desires about how it ought to be you can't see how it is."  http://CLIFFORDRENOVATIONS.COM

7. 
   jimwright | Mar 10, 2003 08:48pm | #11

   Ive always used 1 layer of mesh(4" wide ). Ask your local durock seller(but not Menards Home Depot or Lowes