QUESTION

What is the correct adhesive for installing my ceramic mural? One more question on mortar for setting ceramic tiles in a mural: you recommended a thinset mortar conforming to ANSI A118.11, on 1/4" concrete Hardiebacker board screwed and glued to 3/4" plywood.

I built the mural frames, complete with Hardiebacker board, and ordered the mortar, but received Rapid Set Mortar Mix (high strength construction mortar, to be applied 1/2 to 6" thick), conforming to ASTM C928 and ICC 5102. It states on the label it can be used with ceramic tile, as well as just about everything else mortar is used for.

Is this a suitable mortar for my mural?

ANSWER

ANSWER - I had said to use the ANSI A118.11 if you were bonding to wood, although it also works to bond to concrete or backer boards.

If you are bonding to Hardiebacker board, I think they recommend a regular ANSI A118.4 modified thin-set mortar.

If the Rapid Set Mortar Mix says it is a construction mortar that can be applied from ½” to 6” then that is not a thin-set adhesive and you should not use it to adhere the ceramic tiles to the Hardiebacker board.

The ANSI A118.4 modified thin-set mortars come in standard and rapid versions.  I don’t see why you would want to use the rapid version unless timing is important.  The tradeoff is the thin-set can set off too fast that doesn’t give you adjustability and it can be problematic if you are used to using them.