Black Mosaic Glass Backsplash

This homeowner chose a black mosaic glass backsplash to match his darker counters.

There was no trim available for this glass backsplash.   I pulled off longer strips of tile and ran them perpendicular, length-wise, at the open edges of the backsplash to serve as trim pieces.

Special problems with setting thin mosaic glass

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This kitchen backsplash was tiled in ultra thin 4mm glass mosaic.  The tile was difficult to work with for a variety of reasons.  Following the manufacturer’s instructions I used a 3/16″ v-notched trowl to spread white thinset.  I was then instructed by the company to knock down the ridges with the flat side of the trowel.

Because there were a lot of clear glass pieces on each sheet the manufacturer recommended using only white thinset and knocking down the ridges so that the thinset corrugation could not be seen through the tiles.  The instructions then said to beat the tile into the thinset with a stiff rubber grout float.  Once the first sheet was set I did a test to make sure enough of the thinset was covering the backs of the tiles by pulling that sheet off the wall.  Once that sheet was removed we discovered there was only 5% coverage at best–industry standards call for 85%.  Despite following the manufacturers instructions, we had to modify the way the thinset was applied.  We ended up doing a much thicker application of thinset, which then caused the thinset to ooze between the tiles when the tile sheets were pressed down.

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One of the other difficulties is that the back of the tiles were not connected to a mesh backing.  Instead the tile had very strong plastic adhesive tape on its face holding the pieces onto a 12×12″ sheet.  The manufacturers instructions indicated that the tile had to be in contact with the thinset for at least 24 hours prior to taking the tape off the face of the tiles.  

The next day we cut through the plastic facing every 4″ then peeled off the tape, exposing the overflowing thinset partially covering the face of the tile.  Since the customer insisted on charcoal grey grout two of us had to painstakingly clean out all the grout joints using razor knives so that the white thinset would not show through onto the dark grey grout.  Thankfully the plastic caused the thinset to cure more slowly, so it was easier to remove than had it dried rock-hard.  However, it still took a total of fourteen combined hours to remove overflowing thinset from 22 square feet of 3/4″ tiles.