Q:
In the “Q&A” column of FHB #126, Pat Wehrman’s suggestions for creating a removable tile mural were fine for most dry installations, but her approach could seriously compromise the water-resistant integrity of the walls for wet installations such as showers or tub surrounds. What does Pat recommend in these situations?
Jim Hassberger, Livermore, CA
A:
Pat Wehrman of Dodge Lane Potter Group in Sonora, California, replies: Making a mural removable in a wet application is a little different, but not impossible. First, the backerboard that you mount the mural on should be impervious to water (many are not). One such product is Dens-Shield, made by Georgia-Pacific (800-284-5347; www.gp.com). And the shower wall should be prepared as you would a regular shower with a felt-paper membrane under the backerboard.
Mount the mural on a piece of backerboard cut so that the edge of the board falls in the middle of the rows of field tile on all four sides of the mural (or at least 2 in. beyond the edge). A matching hole should be left in the backerboard on the wall. As with a dry installation, strategic tiles should be loose where the board attaches to the framing behind the mural, and the hole’s sides should be blocked to support the board’s edges.
Screw the backerboard with the mural attached into place using stainless-steel screws. Take a photograph to record the loose tiles as well as the excess backerboard surrounding the mural. Next, tape and mud the seam between the mural board and the wallboard, and install the field tile using latex-modified mortar. I’d seal the screw heads under the loose tiles with silicone, and then install the loose tiles with dabs of silicone, just as with a dry installation. The whole tile job should then be thoroughly grouted and sealed.
The row of field tile closest to the mural bridges the backerboard seam and helps to make the installation waterproof. This row of field tile is sacrificial and has to be broken out when you’re ready to remove the mural, so keep extra replacements on hand.
