Schluter-DITRA Technical Data Sheet

UNCOUPLING MEMBRANES
3
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/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.
DITRA/DITRA-XL’s waterproofing ability not
only protects the substrate from moisture
and harmful substances, it also slows the
drying of fresh concrete, thus reducing the
chances of cracking and curling.
The free space beneath the DITRA/DITRA-XL
matting provides a route for any residual
moisture in the concrete slab to escape.
This allows the installation of DITRA/DITRA-
XL and the tile covering as soon as the slab
can be walked upon. Vapor management is
also essential for slabs subject to moisture
migration.
Since DITRA/DITRA-XL is virtually
incompressible within the tile assembly,
the advantages of uncoupling are achieved
without sacrificing point load distribution
capabilities. This allows DITRA/DITRA-XL
to be installed in commercial and industrial
applications exposed to heavy vehicular
traffic, provided the type, format, and
thickness of the tile are appropriate for the
application.
Industry standard guidelines referencing
uncoupling membranes over concrete
substrates include method F128 in the
TCA Handbook for Ceramic Tile Installation
and method 311F (Details A, C and D) in
the Terrazzo, Tile and Marble Association
of Canada (TTMAC) Specification Guide
09 30 00 Tile Installation Manual.
Gypsum
Bonding ceramic or stone tiles directly
to gypsum concrete substrates is
generally considered questionable or not
recommended. The challenges associated
with gypsum-based underlayments include
the requirement of an extended drying period
before installing tile and continued sensitivity
to the reintroduction of moisture throughout
the life of the installation. In addition, since
the coefficient of thermal expansion of
gypsum concrete is substantially greater
than that of ceramic tile, shear stresses
caused by temperature fluctuations can
result in delamination or cracking of the
tile covering. This is particularly important
when gypsum concrete is used as a
thermal mass for radiant heated floors.
With the increasing popularity of radiant
heated floors, which typically utilize gypsum
concrete, tile installers need a reliable
installation system to address these issues.
DITRA/DITRA-XL’s uncoupling function
protects the ceramic or stone tile covering
by neutralizing the differential movement
stresses between the gypsum concrete
substrate and the tile, thus eliminating the
major cause of cracking and delaminating
of the tiled surface.
DITRA/DITRA-XL’s waterproofing function
prevents the reintroduction of moisture
to gypsum concrete underlayments,
which, if not prevented, could significantly
compromise performance of the
underlayment and lead to damage of the
tiled surface. The residual moisture in
gypsum concrete is allowed to escape
through the air channels on the underside
of the matting. This is particularly important
since gypsum concrete must dry in order to
gain strength.
Since DITRA/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 gypsum
substrates include methods F180 and F200
in the TCA Handbook for Ceramic Tile
Installation and method 314F (Details B and
F) in the Terrazzo, Tile and Marble Associa-
tion of Canada (TTMAC) Specification Guide
09 30 00 Tile Installation Manual.
Heated Floors
Radiant heating is one of the fastest
growing market segments in the
construction industry. Unlike other surface
coverings, the low thermal resistivity of
ceramic and stone tiles allows them to be
used in radiant heat applications without
sacrificing the energy efficiency of the system.
However, there are inherent challenges
in combining rigid surface coverings with
radiant panel heating systems. A viable
installation system must address the
magnified fluctuations in temperature that
contribute to increased shear stresses
between the heated assembly and the
tile covering. The system must also limit
thermal striping by promoting even heat
distribution and protect the assembly from
moisture, which is particularly important
when gypsum concrete is used as the
thermal mass. Differential movement
stresses are magnified in radiant-heated
floor applications because of significant
temperature gradients.
DITRA/DITRA-XL’s uncoupling function
protects the ceramic or stone tile covering
by neutralizing the differential movement
stresses between the heated assembly and
the tile, thus eliminating the major cause
of cracking and delaminating of the tiled
surface.
DITRA/DITRA-XL’s waterproofing function
provides simple, effective, and permanent
protection for moisture-sensitive substrates,
such as gypsum concrete and wood, used
in heated floor applications.
UNCOUPLING MEMBRANES
3