You would be better asking that question here: http://www.johnbridge.com/vbulletin/
I am in the process of installing waterproofing system for a shower wall.
I know this is a plumbing forum, and my question is more for tiling professionals, but I appreciate the level of expertise here, and hope there are a few people out there with some experience on the following products:
1) Kerdi Membrane
2) Mapei Aqua Defense
Item 1) makes sense to me, but I'm told it requires unmodified mortar, which doesn't make much sense. Using a mortar which offers no plasticity seems like a great way to have your shower membrane sheer off from your backerboard.
Item 2) offers serious plasticity, and my tile suppliers use it on their jobs and recommended that I use it. I'm leaning in this direction, but the idea of just painting on a waterproofing system, well, I'd like to hear from more people who have used the product, for better or for worse.
Thanks in advance,
The fleece on the Kerdi membrane gives it a microscopic amount of flexibility in shear. Under any normal circumstances, you'd likely crack the tile or wall before you sheared off the membrane when properly installed.
Important note - I'm not a pro
Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013
Foot man there are more points to the puzzle. We noticed a few months back that some Aquadefence ripped right off the wall in massive sheets. This happened when the framers came back to demo a short wall that was framed wrong and then waterproofed by me.
The ease in which the liquid membrane came off was alarming. We are not in the habit of demo'ing our work so we had never seen this before.
We started skimming out our boarding work so that the entire board was skimmed or scratch coated with thinset before waterproofing. We still tape the seams but skim out all walls.
This has greatly increased the bond strength on the liquid membranes.
This summer I had another "Bubbling Issue" with Aquadefence durning a three day flood test. I quit using the product after this and made the switch to cementious membrane called 8+9. I'm still testing and playing with the product but love the difference in strength over liquids.
Kerdi DS is finally here from Germany. This might become my new goto system since when used in conjuction with Ardex setting materials you get the benifit of extended warranties and local tech support. We have almost finished out first Kerdi DS 8+9 hybrid shower and it is pretty special.