Replies

1. 
   Boxduh | Jan 20, 2003 12:58am | #1

   Everybody uses it here.  And try their fabric-faced membrane for doing shower pans and shower walls, too.  No one here is using cement board anymore.

1. 
   timkline | Jan 20, 2003 05:06am | #2

   What is it  ? I see a membrane product on their website, but I don't see and underlayment product.

   carpenter in transition

1. 
   Boxduh | Jan 20, 2003 06:01am | #3

   Ditra is the waffle-like membrane used under floors.  What I am talking about is the flat membrane, fabric-faced, for use behind and under shower tile.  It is called Kurdi, I believe.  Keep looking.  For a shower, you use moisture resistant drywall, then pop in a mud pan, without a membrane under, but using Schluter's drain, and the Kurdi membrane "washer" that installs with the drain, then Kurdi the whole enclosure, shingle-lapping, bonding the Kurdi to the pan and sides with thinset.  Then tile over.  There is a video at their website of a guy doing a whole shower, from the drain on up.

1. 
   Davo304 | Jan 20, 2003 07:15am | #4

   Could you post a link to this Ditra website?

   Thanks

1. 
   timkline | Jan 20, 2003 07:19am | #6

   http://www.schluter.com/index.html

   Could this be it ?

   carpenter in transition

2. 
   Davo304 | Jan 20, 2003 08:52am | #7

   Tim, Thank You.

   Davo

3. 
   Boxduh | Jan 20, 2003 04:07pm | #8

   The Kurdi fabric provides all the waterproofing you need for a shower.  Use the drywall underneath, and save the cement board for the fireplace front or something.  Try it on a small scale, if you like.  Get a little, make a small OSB box, say 24x24x24, no top, and thinset-bond a Kurdi floor in the bottom, lapped up 3 inches on the walls, then do the walls, lapped over, with the corners lapped.  Do it like you see it done in the video.  Then fill the box with water, and watch it for a few weeks.  I'll bet your OSB stays bone-dry.  The Kurdi membrane, being a polymer, can stretch and move if the substrate does, and will remain a solid long-term barrier.  The Germans, Dutch, and Swiss, all believe in it, and they build for the long haul.

2. 
   timkline | Jan 20, 2003 07:17am | #5

   Thanks for the response. I'll have to check out the video. I now understand the process although I don't understand taking a chance with MR drywall in a shower stall. Why do you want to save $100 in material in a $3000 shower stall by replacing cement board with a drywall product ? A leak in an adjacent sink could cause the shower to fall apart, not to mention a pinhole in this membrane. This sounds like an interesting idea, though. How much does the material cost per sq.ft. ? It's pretty rare that I hear about shower stall walls leaking that use cement board for a substrate. Is there an advantage to this product ?

   carpenter in transition

2. 
   Scooter1 | Jan 20, 2003 09:04pm | #9

   My experience with Ditra is one time. The stuff is impossible to get, and must be special ordered. It is a waffle plstic type stuff, a tad less than a quarter of an inch thick. It comes in rolls and one spreads modified thinset onto the substrate and then the Ditra. Then the tile.

   Advantages: This is a nice way to tile over plywood, without concrete board. It also adds a bit of waterproofing, allbeit not much. Finally, due to thickness, it doesn't add much elevation to the tile job.

   Disadvantages: Expensive. Hard to Get. Must buy full rolls to make it worthwhile. Hard to install, as it likes to curl on you.

   I won't use it again unless the job is over plywood and the elevation specs are such that quarter inch Hardi won't do.

   Kerdi is a waterproof matting that goes over the setting bed. It is used as a waterproofing membrane for floors and yes, showers. If used for showers, you must use the Shulter drain. No pre-slope or membrane sandwich is needed. If the installation is on floors, just tile away on the flat substrate; if on a shower floor, one must still slope the floor. Advantages: Less labor. Disadvantages: Not code in most areas, expensive, must use proprietory drain. I haven't used it yet, 'cause it aint Code here.

   Regards,

   Boris

   "Sir, I may be drunk, but you're crazy, and I'll be sober tomorrow" -- WC Fields, "Its a Gift" 1927

1. 
   RogerDumas | Jan 21, 2003 01:11am | #10

   I'm using it for the first time based on advice I got here.  It's easy to use and I can see how it'll work to prevent cracks.  It's a nice product.  But, yes, it's expensive.  I'd recommend it to anyone who doesn't mind paying a little more.

   Here's a pic... 

   If ignorance is bliss then apathy is sheer heaven...