Installation Guide
STEAM ROOM ASSEMBLY — Schluter
®
-KERDI-DS waterproofing membrane 19
Areas of Application
• Interior continuous use steam rooms (e.g., applications in spas, fitness
centers, etc.).
• Over wood or concrete subfloors. See the Base information under
Requirements (below) for details.
• Areas requiring disabled access/curbless applications; see detail K-SHBF on
page 12.
Limitations
• Certain glass tiles may not be compatible with bonded waterproof membranes
and/or may require special setting materials. Consult glass tile manufacturer
and Schluter
®
-Systems for more information.
• Certain moisture sensitive stones, e.g., green marble, or resin-backed tiles
may not be appropriate for use in wet areas such as steam showers or
may require special setting materials. Consult stone supplier and Schluter
®
-
Systems for more information.
• When KERDI-BOARD is used, steam room must be operated in a manner
such that the maximum service temperature of KERDI-BOARD 158°F (70 °C)
is not exceeded.
• Gypsum-based solid backing panels shall be limited in use to intermittent use
steam showers (e.g., residential applications)
• Do not use sawn lumber curbs on concrete subfloors subject to
moisture migration.
• KERDI-BOARD not for use in exterior applications.
Requirements
• Plywood, OSB, or concrete subfloor must be clean, even, and load bearing.
• Ensure suitable and structurally sound construction for the shower floor. This
may require the services of a qualified design professional (e.g., architect,
engineer, etc.).
• Provide insulation in wall and ceiling cavities to reduce moisture condensation
on the tiled surface.
• Solid backing – KERDI-BOARD, cementitious backer unit, fiber-cement
backerboard, Portland cement mortar, concrete, or masonry.
• Base – Portland cement mortar bed.
• Curb – KERDI-BOARD-SC, KERDI-BOARD, concrete, masonry block, or
sawn lumber sheathed with solid backing (see above).
• Bench – KERDI-BOARD, KERDI-BOARD-SB, concrete, masonry block, or
sawn lumber sheathed with solid backing (see above).
• KERDI-DRAIN/-LINE shall be properly supported.
• KERDI-DRAIN/-LINE shall be connected to the waste line; use ABS cement
for ABS drains, PVC cement for PVC drains, a no-hub coupling for stainless
steel drains with no-hub outlets, and thread sealing compound or tape for
stainless steel drains with threaded outlets.
• Slope ceilings 2" (50 mm) per foot minimum to avoid condensation from
dripping onto occupants (may be sloped to center to minimize rundown on
walls).
• Minimum KERDI-BOARD thickness – 1/2" (12.5 mm) for studs spaced at 16"
(40.6 cm) o.c. and 3/4" (19 mm) for studs spaced at 24" (61 cm) o.c.
• KERDI-BOARD shall be fastened to wood or metal framing with appropriate
screws (i.e., coarse thread wood screw for wood studs and self-tapping for
metal studs) and corresponding KERDI-BOARD-ZT washers. Screws must
reach a depth of at least 3/4" (20 mm) in wood studs and 3/8" (10 mm) in
metal studs. Maximum allowable on-center fastener spacing is 12" (30 cm)
for walls and 6" (15 cm) for ceilings.
• Install KERDI-DS waterproofing membrane on all surfaces, including
the ceiling. For enclosed areas, also install on door jambs, door header and
past the door frame gasket, as applicable.
• It is the specifier's responsibility to treat and address all penetrations through
the KERDI-DS membrane (e.g., steam inlet, lights, etc.) in the installation. All
penetrations must be treated with KERDI-FIX, KERDI-SEAL-PS/-MV seals,
room temperature vulcanizing sealant, or other suitable sealant. Steam
inlets must be treated only with KERDI-SEAL-PS seals, room temperature
vulcanizing sealant, or other suitable sealant. KERDI-FIX is not suitable for
use around the steam inlet.
• When using the stainless steel KERDI-DRAIN bonding flange, use
KERDI-FIX to bond KERDI-DS to the drain.
• Schluter
®
-DITRA-HEAT-E-HK heating cables must be spaced a minimum of 8"
(200 mm) from steam inlets in intermittent use steam showers and continuous
use steam rooms.
• Movement joints shall be provided at all changes in plane, including floor/
wall, wall/wall, and wall/ceiling transitions. Schluter
®
-Systems prefabricated
movement joint profiles (e.g., DILEX-EKE) provide a maintenance-free
alternative to sealant; see page 40.
• All horizontal surfaces (e.g., benches, curbs, window sills, shelves, etc.) must
be sloped toward the shower drain.
Substrate Preparation
• Verify that subfloor panels and solid backing are properly fastened to framing
members.
• Any leveling of the subfloor must be done prior to installing
KERDI-SHOWER-R and KERDI-BOARD-SC/-SB.
Solid Backing Materials
• KERDI-BOARD
• Cementitious backer unit – ANSI A118.9 or ASTM C1325
• Fiber-cement backerboard – ASTM C1288
• Portland cement mortar – ANSI A108.1B
• Concrete
• Masonry
Setting and Grouting Materials
• Unmodified thin-set mortar – ANSI A118.1
• Grout – ANSI A118.3, A118.6, A118.7
Installation Specifications
• Solid backing panels – follow manufacturer’s directions
• Portland cement mortar bed – ANSI A108.1B
• Tile – ANSI A108.5
• Grout – ANSI A108.6, A108.10
Other Considerations
• Shower grab bars must be anchored in the structure or solid blocking behind
KERDI-BOARD.
• When KERDI-DS and tile are installed on the ceiling, the solid backing and
fasteners must be able to support the load of the tile and setting and grouting
materials.
• A water test is strongly recommended before setting tile to verify a successful
installation. Wait 24 hours minimum after the membrane installation is
complete to allow for final set of thin-set mortar and ensure waterproof
performance at seams and connections. Refer to local plumbing codes for
any specific requirements in your area.
• Schluter
®
-Systems profiles may be used to finish and protect outside corners
and eliminate the use of sealant at inside corners; see page 40.
• Schluter
®
-SHOWERPROFILE-S/-R profiles eliminate the need for cutting
wedges of tile by covering the exposed wall area where the floor slopes to
KERDI-LINE.
• Schluter
®
-SHELF-E/-W/-N are alternatives to tiled shelves that can be easily
installed on walls and in corners and niches; see page 40.
• Where a waterproof floor adjacent to the shower is desired, DITRA or DITRA-
HEAT uncoupling membranes shall be installed. Floor/wall connections shall
be sealed with KERDI-BAND.
Continuous Use Steam Rooms – Ceramic or stone tile
Schluter
®
-KERDI-DS waterproofing membrane
K-SR-22