Schluter is smart in choosing their words. If they never say it, they haven't said it.

Kerdi and thin glass may be incompatible because of the additional thickness of Kerdi on the overlaps. Some glass mosaics are made of 1/8" thickness tiles. Workarounds can be found. But Kerdi loses the advantage of time and ease, and other membrane types look better.

Kerdi and large glass tiles may be incompatible because of the type of thinset. Before we can discuss all this, someone has to report back after a phone call to Schluter. A modified thinset is used here or there, or an "unmodified" thinset. That's with or without the latex additive. Glass tile manufacturers may insist on one or the other, and Schluter may insist on the opposite. Avoiding mentioning glass tiles is one good way to avoid the issue.

Hth

Unmodified mortars will cure without the presence of air. Modified types must have air, so if you sandwich them between two impermeable materials like glass or porcelain and a membrane, modified stuff will take forever to cure, as air is only admitted @ the grout lines. Small mosaics have enough grout line area so the curing is not really an issue.
disclaimer: I'm probably wrong.
Casey

Glass and Kerdi are fine together.

The only reason I would think that would cause a conflict is the fact that Schluter recommends the use of unmodified thinsets over Kerdi, and all glass tiles recommend the use of a very highly modified thinset. To that end, I say there's still no problem. When I do a Kerdi shower, regardless of Schluter's recommendations, I still use the most modified "mix with water" thinset that Laticrete makes-- their 255 non-sag. That's with ANY tile-- ceramic, porcelain, stone, or glass. It just so happens it's also very highly recommended by many glass companies. Many will tell you that the minimum would be their 254 Platinum. The 255 is actually a step above that.

I just gave the long winded version of Mongo's post--

Glass and Kerdi are fine together.

Of course, Glass goes great with the hybrid installation using Schluter's drain and Laticrete's Hydroban roll on waterproofing, as well. ;-)

Then you don't have to worry about the seam build up that David spoke of, and Laticrete WILL back the installation. Completely seamless.

I would not be installing glass tile over Kerdi. Not unless I get a letter of permission from Schluter head office.

If you are in this pickle before purchasing your Kerdi - switch hats and use Nobel TS. If the Kerdi is all ready installed call Schluter for an OK. Hold off on the install until you get one.

Schluter reps have been known to tell the tile boys in their towns it's OK to use modified and the best installers in NA (like Bill) understand how to pull it off. For the average installer or DIY you can cause lots of problems and in the end have lost your warranty.

We stopped using Kerdi nearly 18 months ago because of this crazy warranty issue of Schluter. It's wrong they strip the warranty when modified thinsets are used - and they make getting one near impossible. In fact I know of not one single person every to receive one. Lots of advice will tell you its Ok or it will work - but don't you want to hear it from the company themselves?

Since we switched to Hydro Ban and Nobel TS our installs are better and have a longer warranty. Just doesn't make sense to loose your warranty as a DIYer.

JW