I changed the entrance of my shower tub. The panel board was moldy; water was getting in between the top tiles and the panel board. the joint was not well sealed. I put new everything for the entrance, even a membrane between the plywood and the tiles. However, it seems to leak from the wall now. Water is coming out of the wall outside the shower tub. Would it be the grout, tiles...? Tiles and grout are probably 20+ yrs old ( turquoise tiles). I tried to put some ready grout ( in a tube), but it still leaks! Calking is well done. Should I remove the old grout and put new one everywhere? Thanks for your help!

What do you think, is Ditra worth the money? It's a good product but there is much better preforming options with less thin-set restrictions. Why not prepare the floors with Ardex 8+9? The cost is lower and Ardex 8+9 is also rated as a crack isolation membrane where Ditra is not. Ardex 8+9 is waterproof as well without all the banding work Ditra requires. ARDEX 8+9: Concrete sub floor This is the first coat of Ardex 8+9 over a concrete sunroom floor here in Vancouver. Crack isolation membranes should measure three times the length of the tile. Most crack isolation membranes are between 3'-6'. Since this room will get a 3' wide tile I needed one huge sheet. This is where the cementious memebrane from Ardex excels. I also like that there is no voids under the membrane for little silver fish bugs to crawl around in and make homes. I find silver fish a problem in many Vancouver high rise condo's and try and stop them from making new homes on my projects. Does your answer change if we install slate rather than porcelain? All the more reason to use Ardex or NobleSeal CIS. Both those tile choices will want to see a modified thin-set used.

I heard back from Schluter. Here's my question and their answer: Question: Can the uncoupling membrane be installed directly over existing ceramic tile? This is a basement - the tile is installed over the concrete subfloor. Tile is in good shape - just ugly. We don't want to remove it. So if the membrane can be installed over top, what type of thinset should we use to bond the membrane to the existing tile? Answer: If the following requirements are met, we expect this type of installation to be successful. However, given the wide range of potential existing conditions, this application is not covered by a specific detail in the Schluter-DITRA Installation Handbook and is therefore not covered under warranty. In principle, DITRA can be installed over existing tile. In general, the following minimum requirements must be met for a successful installation. The substructure must be adequate, per the DITRA Installation Handbook (e.g., joist spacing, plywood thickness, etc). The existing tile must be well bonded; any loose tile must be removed. The tile must be cleaned before the DITRA installation to remove any bond breakers. The DITRA can be installed in a similar fashion to what is called out in detail D-V-T in the DITRA Installation Handbook. (I looked this up, and it's referring to installing over vinyl.) Option 1. Use a rapid-setting modified thin-set mortar suitable for bonding to existing tile to install the DITRA Option 2. Skim coat the tile with a modified thin-set mortar or suitable cement-based embossing leveler, allow it to dry, and install the DITRA with unmodified thin-set mortar For further details please see attached Ditra installation Handbook

Flexbone is the superior product for most situations that truly need uncoupling. But, the whole project needs to be deconstructed and examined as to the actual needs of the job site. Are you looking for crack isolation? Waterproofing? Exactly what conditions are prompting this unanswerable question in a vacuum?