Specification

UNCOUPLING MEMBRANES
3
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.
DITRA and 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 and
DITRA-XL matting provides a route for any
residual moisture in the concrete slab to
escape. This allows the installation of
DITRA and 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 and DITRA-XL is virtually
incompressible within the tile assembly,
the advantages of uncoupling are achieved
without sacrificing point load distribution
capabilities. This allows DITRA and
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 TCNA Handbook for Ceramic,
Glass and Stone 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 and 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 and 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 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 gypsum
substrates include methods F180
and F200 in the TCNA Handbook
for Ceramic, Glass and Stone Tile
Installation and method 314F (Details B
and F) in the Terrazzo, Tile and Marble
Association 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 and 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 and DITRA-XL’s waterproofing
function provides simple, effective, and
UNCOUPLING MEMBRANES
3