What do we need to consider when installing 18x18 inch tiles on walls?


We’re wanting to install ceramic tile 18”x18” on two walls of our bathroom. Are there special considerations? Do we need to lay a row and let it dry, then add the next? Different glue/mud or trowel size? Thanks!
Jennifer Brown


ANSWER - First of all you need to make sure that the substrate to which you will be adhering the tiles are suitable for the application.  In bathrooms you want to use materials that are not moisture sensitive.

Cement mortar beds are the best substrate if you have the skill for installing mortar beds.  Cement backer board or other tile backer boards that are not moisture sensitive will work as long as they are properly attached and shimmed to be plumb and square. You might want to consider painting a liquid applied waterproof membrane over the wall and floor substrate if you are installing the floor at the same time.  This will help contain water in the bathroom if there was a leak in order to limit collateral damage.

For installing large porcelain tiles you need to use a non-sag thin-set mortar that at least meets the requirements of ANSI A118.4 or ANSI A118.15.  They will have less of a tendency to slide down the wall.  Although you still need to use spacers/wedges between the tiles to help hold them in place as the adhesive cures.  For sure start installing at the bottom and work up, but you don't have to wait for the first row to dry.  You may need to shim up the first tile to hold it in place.

Make sure you use a 1/4 x 1/4 inch square or v-notch trowel.  Or get a Euro Trowel or slanted trowel that will help ensure you get full contact between the back of the tile and its substrate.

Also before you start installing the tile layout it by measuring the wall and determining if you are going to have a cut tile at the top.  You could consider have the tile at the top be a full tile or have the bottom and top tiles be both cut tiles to give symmetry.   It just depends on where the focal points are and what your preferences are.  Make sure you install movement joints at the perimeters of the tile installation.

Download our free installation guidelines that you can find in the same Ask the Expert section of our website.

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