Renovator8-the original paperwork description simply states "apply tar-based foundation coating and install buried liner system". To me the liner looks compatible with 6 ml visquen polyethylene. Tar may be roofing cement aka mastic. I have asked for a better written explanation of what precisely was done from the company and it has not been forthcoming. That was before I grasped the significance of the liner's unevenness and lack of being secured. I didn't know to ask these questions before the job, which makes me feel even worse. It's a highly positive reviewed company so I don't understand just what went wrong with our job such that I can't even grade now. This post was edited by SparklingWater on Tue, Sep 2, 14 at 9:29

I'm new here, joined just this past weekend, but my input would be to leave well enough alone. Hindsight being 20/20, perhaps you'd have done it differently. And in the future, you will. In this case, you didn't, and as DH often tells me, ''if-dog-rabbit.'' Saving $400 to not use the waterproofing at the outset and now to consider throwing an additional $2000 at the completed project, for a fix that would potentially be the most half-assed way to do it, seems questionable to me. On top of that, the original work was done by a man with a good reputation and messing with it at this point might cause him to withdraw his original workmanship guarantee. Honestly, you have the best of all worlds right now. You were lucky enough to have a good worker to begin with, saved the original $400, plus you have the opportunity to check in the situation behind the walls to catch any problems in their infancy. Enjoy the shower, save your $2000 and maybe use it to go on a trip.

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

Well, geez. Who said anything about inadequate backfilling? In our last new build (15 years ago), our builder thoroughly coated the blocked basement walls with "black tar" (I know that's not what it was but for lack of proper terminology right now, let's call it that). He also backfilled with gravel with two layers of of corrugated drain lines (one near the bottom of the walls and one about halfway up that was properly). The gravel went to about 2 ft below grade and then was dirt on top of that. We spent a FORTUNE on gravel on that house. We lived in an area hit heavily by the 2010 floods of Tennessee and Southern Kentucky. If any basement was going to leak, it would've certainly leaked then. Ours didn't AT ALL. My friend's basement filled all the way up to the main level of her house. It was a disaster. These walls are poured concrete this time and the backfilling will be the same as before with the same exterior coating applied. DH's friend (a contractor in the Nashville area) had suggested adding this additional membrane layer as just another layer of protection. I'm simply doing research as to which membrane is most often used and recommended. "It appears you have confused a vertical wall drainage/protection membrane with a waterproofing material so it's difficult to answer your question." And that's quite possible that I did confuse the two but I was hoping the link to the product in the OP would've helped clear up the confusion as to what specific type product I was looking at :)