Installation Guide

Areas of Application
interior showers with curbless access
over wood subfloors. See the Base information under
Requirements (below) for details.
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.
Requirements
plywood or OSB subfloor must be clean, even, and load bearing.
maximum spacing of joists is 19" (488 mm) o.c.
minimum subfloor thickness – 23/32", 3/4" nom. (19 mm)
tongue-and-groove OSB or plywood with 1/8" gap between
sheets. Canada: 19/32", 5/8" nom. (16 mm) tongue-and-groove
OSB or plywood in Canada with 16" (406 mm) o.c. maximum
joist spacing, but 23/32", 3/4" nom. (19 mm) subfloor
recommended.
existing subfloor panels extended over recessed panels to be
installed according to Schluter Wood underlayment fastening
schedule. See Wood Underlayment content in the Schluter
®
-
DITRA Installation Handbook. Our recommendations currently
support only dimensional lumber for floor joists. See alternate joist
manufacturer for attachment specifications. Dimensional lumber
shall not be ripped down from its original dimension and size.
Recessing the floor of a bathroom must be done in a way that
preserves the structural integrity and safety of the construction.
This may require the services of a qualified design professional
(e.g., architect, engineer, etc.). Verify with the local inspector or
authority having jurisdiction (AHJ).
Pre-drill holes in blocking and adjacent supports.
Base – KERDI-SHOWER-T/-TS/TT/-LT/-LTS.
Bench – KERDI-BOARD-SB, KERDI-BOARD, 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.
KERDI, DITRA or DITRA-HEAT shall be installed in all floor areas
subject to water exposure (i.e., wet area and drying area). Floor/
wall connections shall be sealed with KERDI-BAND.
When using the stainless steel KERDI-DRAIN bonding flange, use
KERDI-FIX to bond KERDI to the drain.
All horizontal surfaces (e.g. benches, window sills, shelves, etc.)
must be sloped toward the shower drain. This can be done by
sloping the substrate or the tile.
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-T/-TS/-TT/-LT/-LTS/-SR and KERDI-BOARD-
SB prefabricated substrates.
Setting and Grouting Materials
unmodified thin-set mortar – ANSI A118.1
grout – ANSI A118.3, A118.6, A118.7
Installation Specifications
tile – ANSI A108.5
grout – ANSI A108.6, A108.10
Other Considerations
curbless tiled showers rely on the slope of the floor to effectively
contain water in the immediate shower area and direct water to
the drain. Given the wide range of potential configurations, it isn’t
possible to address them all in this Handbook.
Waterproofing must be installed in all areas subject to water
exposure. Install KERDI over mortar beds and Schluter
®
prefabricated EPS foam substrates. Use the DITRA or DITRA-
HEAT uncoupling membrane over plywood/OSB or concrete
subfloors. All seams are sealed using KERDI-BAND. Please refer
to the Schluter
®
-DITRA or Schluter
®
-DITRA-HEAT Installation
Handbooks for complete details and warranty criteria.
If KERDI-LINE is placed at shower entrance, it is recommended
that grate assembly A, Pure, or the covering support (D) is
chosen and that the drainage openings span the maximum width
of the entrance to limit potential overflow; secondary drainage
(e.g., KERDI-DRAIN) may be required in the drying area.
Schluter
®
-SHOWERPROFILE-WS/-WSK system profiles can be
used to form a splashguard at the entrance of curbless showers.
See Schluter Illustrated Price List for more information.
Various building codes and other sources, such as the Americans
with Disabilities Act, include specific requirements for disabled
access in public buildings and must be consulted when applicable.
Areas of interest may include degree of slope, clearance, and
supporting structures such as grab bars.
When KERDI-SHOWER-T/-TS/TT/-LT/-LTS tray dimensions do
not match the dimensions of the shower compartment, the tray
may be cut or extended with dry pack mortar.
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. For curbless showers a temporary
dam must be provided at the threshold to perform the water test.
Schluter
®
-Systems profiles may be used to finish and protect
outside corners and eliminate the use of sealant at inside corners;
see Schluter Illustrated Price List for more information.
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.
SHOWER ASSEMBLY — Recessed Curbless 15
Recessed Curbless Shower
K-SHCR-20
Curbless Showers – Ceramic or Porcelain Tile