Installation Guide

10 WATERPROOFING — Floors, Interior
Every substrate presents unique challenges
WATERPROOFING
Floors, Interior - Ceramic or Stone Tile
DH-WP-17
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-HEAT and DITRA-HEAT-
TB matting and floor/wall transitions must be
sealed with KERDI-BAND using unmodified
thin-set mortar. Note: KERDI-BAND must lap
DITRA-HEAT at seams and at floor/wall
transitions by a minimum of 2" (50 mm) in
order to maintain waterproof integrity
Other Considerations
seaming DITRA-HEAT and DITRA-HEAT-TB,
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
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-HEAT and
DITRA-HEAT-TB applications. DITRA-HEAT/
DITRA-HEAT-TB 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-HEAT and DITRA-HEAT-TB is sealed
to the KERDI waterproofing collar on KERDI-
LINE using unmodified thin-set mortar.
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 covering above can be damaged as a result.
Typical areas that require waterproofing include tub surrounds and showers. However, 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.
DITRA-HEAT and DITRA-HEAT-TB installations can be made waterproof with minimal effort. Since the matting is made of waterproof
polypropylene, the only extra step necessary is to seal the seams and floor/wall connections. This is easily accomplished by applying
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. KERDI-DRAIN or KERDI-LINE may be used to provide drainage in DITRA-HEAT and DITRA-HEAT-TB
installations.
Tile or wood base
Ceramic, porcelain
or stone tile
RONDEC
DILEX-EKE
Unmodified thin-set mortar
KERDI-BAND
DITRA-HEAT
or DITRA-HEAT-TB
uncoupling membrane
and heating cables
Thin-set mortar
per appropriate
detail