Installation Guide

SHOWER ASSEMBLY — Curbless 13
Areas of Application
Interior showers with curbless access.
Over wood or concrete 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, OSB, or concrete subfloor must be clean, even, and load bearing.
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.).
Solid backing – gypsum wallboard, cementitious backer unit, fiber-cement
underlayment, fiber-reinforced water-resistant gypsum backerboard/
underlayment, coated glass mat water-resistant gypsum backerboard,
Portland cement mortar bed, concrete, or masonry.
Base – KERDI-SHOWER-T/-TS/-TT/-LT/-LTS or Portland cement mortar
bed.
Ramp – KERDI-SHOWER-SR or Portland cement mortar bed.
Bench –KERDI-BOARD-SB, KERDI-SHOWER-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.
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" (61.0 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.
KERDI or KERDI-BOARD shall be installed up to the height of the showerhead
at minimum.
In enclosed shower areas, install KERDI or KERDI-BOARD on all surfaces,
including the ceiling, door jambs and the door header.
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.
Any protrusions through the KERDI or KERDI-BOARD (e.g., showerhead,
mixing valve, etc.) must be treated with KERDI-SEAL-PS/-MV seals, KERDI-
FIX or suitable sealant.
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/-SB/-SR and KERDI-BOARD-SB
prefabricated substrates.
Solid Backing Materials
Gypsum wallboard – ASTM C1396/C1396M
Cementitious backer unit – ANSI A118.9 or ASTM C1325
Fiber-cement underlayment – ASTM C1288
Fiber-reinforced water-resistant gypsum
backerboard/underlayment – ASTM C1278
Coated glass mat water-resistant gypsum backerboard – ASTM C1178
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
If installing the KERDI-SHOWER-TT thin tray, the installation of a 5/8" or 3/4"
plywood/OSB on top of a wood subfloor and Schluter
®
-DITRA-HEAT or
Schluter
®
-DITRA-XL is suggested to create a curbless shower application.
Due to the additional height, be sure to check the transition height at the
bathroom doorway.
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 page 35.
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.
Shower grab bars must be anchored in the structure or solid blocking behind
KERDI-BOARD.
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.
When KERDI or KERDI-BOARD 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. For curbless showers a temporary
dam (e.g., a 2x4 and silicone sealant, plastic sheeting and sand, etc.) 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 page 37.
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.
Curbless Showers – Ceramic or stone tile
K-SHBF-19
Schluter
®
-KERDI waterproofing membrane or
Schluter
®
-KERDI-BOARD waterproof building panel