A.Michael Byrne, a JLC contributing
editor, responds: Your question would be simple to answer
if I could refer only to the tile, but given your uncertainty
about such a basic issue, I wonder what your thinking is on the
other important aspects of the installation? For instance, what
do you consider an “appropriate” thinset? And how
will you be using the Hardiebacker?
This is one of the most difficult of all tile installations
to properly specify and install. First, I would stay away from
using any unglazed tile in this area except for the floor,
where slip resistance is desired. Unglazed tiles in a steam
room may cause maintenance problems because salts tend to build
up in such areas; salts are more easily cleaned off glazed
tiles and may prove difficult to remove from the surface of
unglazed tiles.
Have you checked with the backerboard manufacturer to see if
its product can be used in a steam room environment? Some
backerboards may not be suitable for such use.
You say nothing about how the floor of the shower will be
built. Certainly, you should not expect to use backerboard
there, since the floor must be sloped to the drain. Also,
cement backerboards are known to wick moisture: Therefore, the
junction between the wall and the floor setting bed will
require a waterproofing detail that may differ from one brand
of backerboard to the next.
On steam units, I always recommend a surface-applied
waterproofing membrane (liquid or sheet). Membranes located
behind the backerboard will allow steam vapor to enter the wall
cavity.
I suggest that you obtain a copy of the TCA Handbook
(864/646-8453, www.tileusa.com) for details on steam showers
and other ceramic tile installations. In the meantime, see the
illustration below.
STEAM ROOMS
Membrane
Requirements:
• steam rooms require a waterproofing membrane on all
surfaces to prevent moisture from penetrating adjoining
spaces.
• some membranes will require insulation on walls and
ceilings to protect them from excessive heat.
• slope ceilings (2” per ft. minimum) to avoid
condensation from dripping onto occupants (sometimes sloped to
center to minimize rundown on walls).
Material and Tile Installation:
• attach four equally spaced tie wires to the supporting
members and through the insulation. Attach 1/4” D steel
pencil rods vertically over the insulation. Attach metal lath
to pencil rods on both walls and ceilings.
• install open slip joints in all corners between walls
and ceilings and to divide areas that exceed 16’-0”
in length.
• floors—follow Method F121.
• walls and ceilings–follow Method W221.
NOTE: Waterproof membrane is shown in two different
installation locations on wall. Specify one or the
other.
Requirements:
• steam rooms require a waterproofing membrane on all
surfaces to prevent moisture from penetrating adjoining
spaces.
.• slope ceiling (2” per ft. minimum) to avoid
condensation from dripping onto occupants (sometimes sloped to
center to minimize rundown on walls).
• waterproof membrane must be capable of withstanding heat
exposure.
.Material and Tile Installation:
•tile—A137.1 and certified by manufacturer for wet
environment.
• cementitious backer units—ANSI A108.11 and
A118.9.
bull; reference and follow membrane manufacturer’s
installation directions for placement of membrane.
• install open slip joints in all corners between walls
and ceilings.
• floors—follow Method F121 or F122
• walls and ceilings—follow Method W244 or B415.
NOTE: Any penetration of the membrane should be sealed
with appropriate sealant before installing tile.
Courtesy of the Tile Council of America, Inc., ©
2002