Installation Guide

SHOWER ASSEMBLY — Barrier-free 11
Areas of Application
Interior showers with barrier-free access.
Over wood or concrete subfloors.
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-ST/-L/-LS or Portland cement mortar bed.
Ramp – KERDI-SHOWER-SR or Portland cement mortar bed.
Bench –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 screws
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.
KERDI or DITRA 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.
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-ST/-L/-LS /-SB/-SR 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
Barrier-free 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 uncoupling membrane over plywood/OSB or
concrete subfloors. All seams are sealed using KERDI-BAND. Please
refer to the Schluter
®
-DITRA Installation Handbook for complete details
and warranty criteria.
If KERDI-LINE is placed at shower entrance, it is recommended that grate
assembly A or 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.
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-ST/-L/-LS tray dimensions do not match the
dimensions of the shower compartment, the tray may be cut or extended
with Portland cement 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 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. 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 35.
Barrier-Free Showers – Ceramic or stone tile
K-SHBF-14
Schluter
®
-KERDI waterproofing membrane or
Schluter
®
-KERDI-BOARD waterproof building panel