mosaic glass tile over wallpaper?

bobbo · 02-26-2009, 11:18 AM

planning to install 4' high wall of mosaic tile in bathroom. Should I remove the wallpaper? It is a better idea to screw in concrete boards over the wallpaper?

Bob Mariani · 02-26-2009, 11:36 AM

I would apply a 1/4" cement board. Use thinset not mastic for glass tiles. You also need a glass tile cutting blade, not the regular tile diamond blade to avoid chips in the cut tile.

bobbo · 02-26-2009, 03:18 PM

Great advice on the glass blade Bob!! Excellent explanation. Thank you so much.

What's the reason for using thin set instead of mastic? If I know the reason, then I will NEVER EVER forget about not using mastic on glass tile. Thank you in advance.

JazMan · 02-26-2009, 04:24 PM

If you install glass tile with mastic, we will have to send the "Tile Police".

Is there even a mastic that anyone claims would work?

Same if you install 1/4" CBU over wallboard. !/4" is not stiff enough because it can only be fastened on 16" o.c. It will flex. Plus how will you finish the exposed board where the tiles end?

Obviously this is a dry area (?), so you can install over regular wallboard once the paper and paste is removed. Otherwise remove the wallboard and install 1/2" backer, then tile just a bit higher past the seam.

The blade advice is good though.

Jaz

Bob Mariani · 02-26-2009, 05:13 PM

how would 1/4" over drywall flex? but not the drywall itself.... mastic takes too long to dry under the glass tiles. I never like thinset on drywall. The paper on the drywall absorbs too much of the water in the thinset. Removing the drywall and adding 1/2" backer is not a bad idea either. If using the 1/4" I just build a caulking edge and it seems to look fine. But this may be harder for others with less experience in tooling caulk. I would go with Jazman on this one.

bobbo · 02-26-2009, 11:42 PM

Jazman and Bob, You guys rock!!!! I didnt even think about the seam.

Now, all I have to do is to figure out which will require less work; removing wallpaper or demo wall and install 1/2 cement board.heheeheehehe