About Glass Tile

mscocolat · Joined: 07 Sep 2004 Posts: 1 Location: SF Bay Area

Hi everyone.

I am redoing a tub/shower combo.

Granite tile will be used on and above the tub, vertically transitioning to Oceanside Glass 4x8 field tiles (0.25 in thick), then transitioning to a 12-in wide border of ceramic tile mosaic (.375 in thick), and back to 4x8 glass field tiles up to the ceiling. Vertical edge will be done with the Schluter Rondec in stainless.

My concerns are cracking, the thickness variation, and installation of a frameless glass shower door afterward.

Cracking: I will be following Oceanside's installation instructions, but notice that Interstyle recommends a crack suppression membrane. I will be using Schluter Kerdi membrane - will this be sufficient or do I need a separate crack suppression membrane?

Is it also a good idea to put Kerdi flex between the glass zones and the granite & ceramic zones to allow for variation in expansion/contraction modulus? Is it even better to put something like Schluter Deco between the different tile materials or am I then adding just another material into the mix?

Shower door: should I have the glass tile pre-drilled before installation at the glass shop so the drilling for the shower door mounts does not have to be done post installation (with possible cracking & messy replacement issues)?

Thickness: Since Schluter Ditra is 1/8 in thick, AND uncouples the stresses between the substrate and tile (to some extent), can I use this in just the glass tile area and solve both the cracking and thickness issue together?

Thank you in advance for any advice you can give on these subjects!
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MsCocolat

khauner · Joined: 11 Apr 2004 Posts: 30 Location: Vancouver, Canada

Hi Mscocolat:

It sounds like you have your work cut out for you! Let's see if we can help:

1- Cracking. Glass is not very flexible and will crack if exposed to forces such as bending or pulling (things that may happen near cracks and seams in the substrate). For that reason Interstyle recommends a crack suppression membrane and the use of a flexible thinset mortar with latex additive to contain these forces. Granite and ceramic tiles will also crack when exposed to bending forces, but the effect is less visible. Granite in particular has natural cracks that more easily blend in. Glass on the other has a shiny smooth finish and translucent body that makes any crack very visible.

Here is a difference between Interstyle and Oceanside: Interstyle's tiles generally have a clear body with the color melted into the back of the tile to enhance the appearance of glass. Interstyle also makes larger format tiles, up to 12"x12". All things being equal, larger format tiles can be more prone to cracking than smaller ones. Also, translucent tiles tend to show cracks more; therefore Interstyle says that the installation of anti fracture membranes is mandatory.
Oceanside's tiles, on the opther hand, are more able to hide the effect of cracks because their finishes are rustic and tile modules smaller. Oceanside colors the body of the glass so that the tile does not appear translucent and the color is viewed from the surface. For that reason they do not make anti-fracture membranes mandatory (although in my opinion there is no ill effect in using an anti-fracture membrane in any case: you gain stablility, and some other benefits such as waterproofing).

As for the best brand of crack suppression membranes, you should use the manufacturer as your guide. I looked at the Ditra site (http://www.schluter.com/english/products/2002/sectionf/ditra/601-index.html) and Kerdi http://www.schluter.com/english/products/2002/pdf/Kerdi_20041.pdf and they do not mention glass tile specifically, but I suspect that they work well.

I am not sure I understood correctly, but if you are applying Kerdi under the glass to thicken it, you will only get the benefit of the waterproofing and anti-fracture under the glass tile. Granite is quite porous, and depending on the substrate you may find yourself with a water problem down the road. I would recommend applying an anti-fracture/waterproofing membrane under the entire installation and then adding some more membrane under the glass tile to assist in leveling (you may be doing this anyway, but I thought it should be mentioned). Schluter Deco is only cosmetic and should only be used for decorative purposes (if anything it is likely to leak water into the joint).

As for shower doors, holes can be cut before at a glass shop if needed, or later on site if you have access to a diamond hole saw and water (to cool the blade and protect the diamonds). Keep in mind that you want to make the hole in the glass larger than the anchor, so that the anchor is embedded in the substrate and will not rest (and cause stress) to the glass.

I hope some of this helps. Good luck.
Kim