Use and Care Guide

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UNCOUPLING MEMBRANES
DITRA and DITRA-XL provide reliable
waterproofing in interior applications. Its
polyethylene composition protects the substrate
from moisture penetration, which is particularly
important in today’s building environment where
most substrates are moisture-sensitive.
Vapor management
The distinguishing feature of DITRA and DITRA-
XL is the existence of free space created by the
configured channels on the underside of the
matting. The free space provides a route for
excess moisture and vapor to escape from the
substrate that could otherwise cause damage
to the tile layer above. Thus, DITRA and DITRA-
XL effectively manages moisture beneath the
tile covering.
Support/load distribution
When placed on a solid foundation,
columns or pillars can support tremendous loads.
The same physical principle applies to DITRA
and DITRA-XL installations. Column-like mortar
structures are formed in the cutback cavities
of the matting. Loads are transferred from the
tile covering through these column-like mortar
structures to the substrate. Since the matting is
virtually incompressible within the tile
assembly, the advantages of uncoupling
are achieved without sacrificing point load
distribution capabilities. The ability of DITRA and
DITRA-XL installations to support and distribute
heavy loads while preserving the integrity of
the tiled surface has been verified through
extensive laboratory and field testing, including
applications exposed to vehicular traffic.
Material Properties and
Areas of Application
DITRA and DITRA-XL are manufactured using
high-density polyethylene (HDPE), which does
not rot and is inert, non-toxic, and physiologically
safe. The material is highly resistant to solutions
containing salts, acids, and alkalis, as well
as many organic solvents, alcohols, and oils.
Resistance to specific stresses can be provided
if concentration, temperature, and exposure
time are known. DITRA and DITRA-XL are
waterproof and minimize the transmission of
vapor (water vapor permeance of DITRA is
0.006 perms per ASTM E96).
DITRA and DITRA-XL meet the American National
Standard for Load Bearing, Bonded, Waterproof
Membranes for Thin-Set Ceramic Tile and
Dimension Stone Installations (ANSI A118.10),
are listed by cUPC®, and are evaluated by ICC-
ES (see Report Nos. ESR-2467 and PMG-1204).
For copies of the above listing or report,
please contact Schluter
®
-Systems at
800-472-4588 (USA) or 800-667-8746 (Canada)
or by e-mail at [e-mail]. Links to the
listing and report can also be accessed at www.
schluter.com.
DITRA and DITRA-XL were evaluated
according to the "Standard Method for the
Testing and Evaluation of Volatile Organic
Chemical Emissions from Indoor Sources
Using Environmental Chambers, Version 1.1"
for California Specification 01350 and found to
comply with the VOC requirements. California
Specification 01350 is referenced by various
green building standards and rating systems.
Note: Due to air space within the assembly,
tile coverings installed over DITRA or DITRA-
XL may have a hollow sound when they are
walked upon with hard shoes or tapped with a
hard object.
Suitable Substrates
For complete installation guidelines and
warranty criteria, please contact Schluter
®
-
Systems at 800-472-4588 (USA) or
800-667-8746 (Canada) or by e-mail at
[e-mail] to receive a copy
of the Schluter
®
-DITRA Installation
Handbook and a step-by-step installation
video. To download a PDF version of the
Handbook or to view the installation video
online, please visit www.schluter.com.
All
substrates must be clean, even, and load
bearing. Bond-inhibiting surfaces must be
removed prior to the application of DITRA and
DITRA-XL.
Note: Type, thickness, and format of the tile or
stone surface covering must be suitable for the
intended application. Minimum tile format is 2"
x 2" (5 x 5 cm).
Wood
All wood materials, including OSB, plywood,
and framing members, are subject to
expansion, contraction, bending, and deflection
as a result of changes in moisture content
and loading. Further, these deformations
fluctuate over the life of the building structure.
DITRA and DITRA-XL’s uncoupling function
protects the ceramic or stone tile covering
from the aforementioned deformations by
neutralizing the differential movement stresses
between the wood structure and the tile, thus
eliminating the major cause of cracking and
delaminating of the tiled surface. Therefore,
DITRA and DITRA-XL can replace a second
layer of plywood in most applications. Since
the uncoupling function of the matting is based
on its geometric configuration, the increased
thickness of DITRA-XL results in increased
uncoupling capacity. Thus, DITRA-XL is
optimized for tile installation over bending and
deflecting substrates such as plywood and
OSB, including applications over single-layer
plywood/OSB subfloors on joists spaced at 24"
(610 mm) o.c.
Wood continually absorbs and releases
moisture. The free space beneath DITRA and
DITRA-XL allows the wood to breathe and
provides a route for any residual moisture in the
wood substrate to escape.
Since DITRA and DITRA-XL is virtually
incompressible within the tile assembly, the
advantages of uncoupling are achieved without
sacrificing point load distribution capabilities.
Industry standard guidelines referencing
uncoupling membranes over wood
substrates include methods F147 and F148 in
the TCNA Handbook for Ceramic, Glass and
Stone Tile Installation and method 313F (Detail
D) in the Terrazzo, Tile and Marble Association
of Canada (TTMAC) Specification Guide 09 30
00 Tile Installation Manual.
Note: DITRA and DITRA-XL may be installed over
existing vinyl floors (no cushioned or perimeter
bonded vinyl). However, various steps must be
taken to ensure a successful installation. Please
refer to the Schluter
®
-DITRA Installation Handbook
for details.
Concrete
There are various challenges associated with the
installation of hard surface coverings on concrete
substrates. To begin, the coefficient of thermal
expansion of concrete is close to twice that of
ceramic tile. Additionally, tile contractors are
often expected to install tile over young concrete
(concrete cured less than 28 days). However,
rigid surface coverings installed over young
concrete are susceptible to damage as a result
of shrinkage during curing. Pre-stressed/post-
tensioned concrete slabs are also commonplace
in today’s construction environment. Although
pre-stressing is used to help control deflections
in concrete structures, these slabs are still
subject to deformations caused by changes
in moisture, temperature, and loading. Many
concrete slabs on or below grade are subject to
moisture migration, which can be problematic.
Furthermore, these structures experience the
same deformations as stated above.
DITRA and DITRA-XL’s uncoupling function
protects the ceramic or stone tile covering by
neutralizing the differential movement stresses
between the concrete substrate and the tile,
thus eliminating the major cause of cracking
and delaminating of the tiled surface.
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