Installation Guide

ManualsBrandsSchluter ManualsFloor Patching, Self-Leveling & WaterproofingKerdi 3 ft. 3 in. x 98 ft. 5 in. Waterproofing Membrane

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-ST/-L/-LS 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.

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 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

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 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.

Schluter

-SHOWERPROFILE-WS/-WSK system profiles can be used to

form a splashguard at the entrance of curbless showers. See page 33.

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 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 36.

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-18

Schluter

-KERDI waterproofing membrane or

Schluter

-KERDI-BOARD waterproof building panel