Installation Guide

12 WATERPROOFING — Floors, Interior
Every substrate presents unique challenges
WATERPROOFING
Floors, Interior - Ceramic or Stone Tile
Today’s construction methods, which include the use of lightweight, moisture-sensitive
materials, such as plywood, OSB, and gypsum concrete, have made the installation of
hard surface coverings particularly challenging. If wood or gypsum concrete substrates are
exposed to moisture, the tile layer above can be damaged as a result.
Typical areas that require waterproofing include tub surrounds, showers, and barrier free
showers. Barrier-free tiled showers eliminate the use of a curb and rely on the slope of
the floor to keep water inside the stall, thus improving accessibility. Waterproofing must
be installed in all areas subjected to water exposure in barrier-free shower applications.
Ideally, the entire floor is protected. There are other commonly tiled areas that may, through
unexpected circumstances, become exposed to significant amounts of water; for example,
an overflowed toilet, or ruptured dishwasher, icemaker, or washing machine lines, which can
result in flooding.
Waterproofing these floors can save an owner from replacing the tile assembly and
substructure in the event of a leak. Schluter
®
-DITRA and Schluter
®
-DITRA-XL
installations can be made waterproof with minimal effort. Since the mattings are made of
waterproof polyethylene, the only extra step necessary is to seal the seams and floor/wall
connections. This is easily accomplished by applying Schluter
®
-KERDI-BAND to these
areas using an unmodified thin-set mortar. The result is a waterproof installation that will
not suffer damage in the event of an unexpected water leak. Schluter
®
-KERDI-DRAIN or
Schluter
®
-KERDI-LINE may be used to provide drainage in DITRA and DITRA-XL installations.
DITRA and DITRA-XL meet the requirements of the American National Standard for Load
Bearing, Bonded, Waterproof Membranes for Thin-Set Ceramic Tile and Dimension Stone
Installations (ANSI A118.10), and are listed by cUPC® and evaluated by ICC-ES (ESR-2467
and PMG-1204).
D-WP-17
Tile or wood base
Ceramic, porcelain or stone tile
RONDEC
DILEX-EKE
Unmodified thin-set mortar
KERDI-BAND
DITRA or DITRA-XL
uncoupling membrane
Thin-set mortar
per appropriate
detail
Areas of Application
over any even and structurally sound
substrate where waterproofing is desired
Limitations
minimum 2" x 2" (50 mm x 50 mm) tile
Requirements
all seams in DITRA and DITRA-XL matting
and floor/wall transitions must be sealed with
KERDI-BAND using unmodified thin-set
mortar. Note: KERDI-BAND must lap DITRA
at seams and at floor/wall transitions by a
minimum of 2" (50 mm) in order to maintain
waterproof integrity
Other Considerations
seaming DITRA and DITRA-XL, including
floor/wall connections, with KERDI-BAND
may be appropriate in cases where a break
in the water line of an ice maker or dishwasher
can damage pre-existing moisture-sensitive
substrates and underlayments. KERDI-
BAND floor/wall connections are just as
easily concealed with wood base as with tile.
KERDI-BAND floor/wall connections in
dishwasher alcoves are parged with thin-set
mortar
in some applications the vertical section of
the floor/wall transition will not accept a bond
to unmodified thin-set mortar. Connections
to such elements can be achieved using
Schluter
®
-KERDI-FIX or suitable trowel-
applied waterproofing materials, such as
those that require atmospheric moisture to
cure (e.g., urethane sealant)
KERDI-DRAIN or KERDI-LINE may be used
to provide drainage in DITRA and DITRA-XL
applications. DITRA/DITRA-XL is sealed to
the fleece-laminated KERDI-DRAIN bonding
flange with a section of KERDI membrane
using unmodified thin-set mortar. KERDI-FIX
is used to seal the section of KERDI to the
stainless steel KERDI-DRAIN bonding flange.
DITRA/DITRA-XL is sealed to the KERDI
waterproofing collar on KERDI-LINE using
unmodified thin-set mortar