Installation Guide

BATHTUB SURROUND 21
Areas of Application
• Interior bathtub surrounds.
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 bathtub surrounds or
may require special setting materials. Consult stone supplier and Schluter
®
-
Systems for more information.
• KERDI-BOARD not for use in exterior applications.
Requirements
• Solid backing – gypsum wallboard, cementitious backer unit, fiber-cement
backerboard, fiber-reinforced water-resistant gypsum backerboard, coated
glass mat water-resistant gypsum backerboard, Portland cement mortar,
concrete, or masonry.
• The structure must be designed and built to meet the building code
requirements applicable in your area. This may require the services of a
qualified design professional (e.g., architect, engineer, etc.).
• Solid backing panels or KERDI-BOARD shall either be installed flush with
the tub flange or over the tub flange leaving a minimum space of 1/4"
(6 mm) between the board and the tub deck.
• 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.
• KERDI waterproofing membrane or KERDI-BOARD waterproof building panel
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.
• It is the specifier's responsibility to treat and address all penetrations
through the KERDI membrane or KERDI-BOARD (e.g., showerhead, mixing
valve, etc.) in the installation. All penetrations must be treated with
KERDI-SEAL-PS/-MV seals, KERDI-FIX, or other suitable sealant.
• All horizontal surfaces (e.g., window sills, shelves, etc.) must be sloped
toward the bathtub drain.
Substrate Preparation
• When using KERDI waterproofing membrane, verify that solid backing is
properly fastened to framing members.
Solid Backing Materials
• Gypsum wallboard – ASTM C1396/C1396M
• Cementitious backer unit – ANSI A118.9 or ASTM C1325
• Fiber-cement backerboard – ASTM C1288
• Fiber-reinforced water-resistant gypsum backerboard – 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, or A118.7
Installation Specifications
• Solid backing panels – follow manufacturer’s instructions
• Portland cement mortar bed – ANSI A108.1B
• Tile – ANSI A108.5
• Grout – ANSI A108.6, A108.10
Other Considerations
• 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.
• Shower grab bars must be anchored in the structure or solid blocking behind
KERDI-BOARD.
• Schluter
®
-Systems profiles may be used to finish and protect outside corners
and eliminate the use of sealant at inside corners; see page 43.
• Schluter
®
-SHELF-E/-W/-N are alternatives to tiled shelves that can be easily
installed on walls and in corners and niches; see page 43.
• Where a waterproof floor adjacent to the bathtub is desired, DITRA/-XL
uncoupling membrane, DITRA-HEAT/-PS or DITRA-HEAT-DUO/-PS electric
floor warming and uncoupling membrane shall be installed. Floor/wall
connections shall be sealed with KERDI-BAND. Completely fill the gap
between the tub and DITRA/-XL, DITRA-HEAT/-PS or DITRA-HEAT-DUO/-PS
membrane with KERDI-FIX or other suitable sealant.
Bathtub surround – Ceramic or stone tile
Schluter
®
-KERDI waterproofing membrane
or Schluter
®
-KERDI-BOARD waterproof building panel
K-TS