Installation Guide

INSTALLATION 15
Schluter
®
-DITRA-HEAT membrane and heating cables
INSTALLATION
Preparation
• The substrate must be clean, even, and load bearing. Any leveling of the subfloor must be done prior to installing DITRA-HEAT and DITRA-HEAT-TB.
• For wood substrates, verify that panels are properly fastened. Tightly butted and/or tented plywood or OSB seams must be addressed prior to installing DITRA-HEAT and
DITRA-HEAT-TB. If a plywood/OSB underlayment is to be installed, follow the Wood Underlayment guidelines on page 14.
• For vinyl substrates, ensure that the structure beneath is sound and adequate and that the vinyl is well adhered. Remove any wax and clean the surface. For vinyl over wood
structures, nail off floor with ring shank flooring nails every 4" (102 mm) o.c. - fasteners must pass through entire thickness of assembly with minimal penetration into joists.
• For concrete substrates, remove any waxy or oily films and curing compounds (if present) by mechanical scarification. When bonding DITRA-HEAT and DITRA-HEAT-TB to
particularly dry, porous concrete, the slab should be moistened to saturate the concrete and help prevent premature drying or skinning of the bond coat. Excess or standing
surface water must be removed prior to installation.
• For gypsum substrates, residual moisture in gypsum screed must be 2.0% or less before installing DITRA-HEAT and DITRA-HEAT-TB. Follow gypsum manufacturer’s directions
for additional substrate preparation.
Membrane
Using a thin-set mortar that is suitable for
the substrate, apply the thin-set mortar
(mixed to a fairly fluid consistency, but still
able to hold a notch) using a 1/4" x 1/4"
(6 mm x 6 mm) square-notched trowel.
1
Apply DITRA-HEAT or DITRA-HEAT-TB to the
floor, fleece side down. Solidly embed the matting
into the mortar using a float, screed trowel, or
DITRA-ROLLER, making sure to observe the open
time of the bonding mortar. If the mortar skins over
prior to matting installation, remove and reapply.
Note: It may be helpful to back roll the end of the
matting before installation, or place boxes of tile on
top of the matting after installation, to avoid curling.
2
When using the DITRA-ROLLER, place a weight (e.g.,
bags of mortar/grout or box of tile) not to exceed 75
lbs on the DITRA-ROLLER shelf. Slowly move the
roller from one end of the matting to the other, slightly
overlapping successive passes.
Lift up a corner of the matting to check coverage.
Proper installation results in full contact between
the fleece webbing and the thin-set mortar. Note:
Coverage may vary with mortar consistency, angle
at which the trowel is held, substrate flatness, etc.
If full coverage is not achieved, remove and reapply,
making sure to verify proper mortar consistency and
application.
3
Abut end and side sections of adjacent sheets.
Note: Aligning the studs on the top of the matting
during installation can help make subsequent
heating cable installation easier.
4
ESTIMATED THIN-SET COVERAGE
To bond DITRA-HEAT to the substrate:
Use one 50 lb. (22.68 kg) bag of mortar per
100 ft
2
(9.3 m
2
).
To bond the tile to the DITRA-HEAT, using a
1/4" x 3/8" (6 mm x 10 mm) square- or
U-notched trowel: Use one 50 lb (22.68 kg) bag
of mortar per 40 - 50 ft
2
(3.7 - 4.6 m
2
).
To bond the tile to the DITRA-HEAT, using a 1/2"
x 1/2" (13 mm x 13 mm) square- or U-notched
trowel: Use one 50 lb (22.68 kg) bag of mortar
per 30 - 40 ft
2
(2.8 - 3.7 m
2
).
Planning
For access to the DITRA-HEAT Calculation Sheet and DITRA-HEAT Online Calculator, see www.schluter.com.
• Select DITRA-HEAT and DITRA-HEAT-TB membrane according to the size of the area to be tiled.
• Select DITRA-HEAT-E-HK heating cable according to the size of the area to be heated. Be sure to measure accurately. The heating cable CANNOT be cut to fit. The allowable
heated area is limited by the minimum required spacing from fixed elements such as:
• Walls = 3" (75 mm)
• Fixed cabinets = 2" (50 mm)
• Heat sources (baseboard heaters, fireplaces, forced air heating ducts, etc.) = 8" (200 mm)
• Floor drains = 6" (150 mm)
• It is helpful to plan the location of a buffer zone, as it is not possible to predict exactly where the heating cable will end. The buffer zone is an area where floor warming
is not essential and heating cable installation is not planned (e.g., behind a toilet or adjacent to a door opening). This area allows for placement of excess heating cable.
Heating cables may also be installed 6" (150 mm) from the wall to create a buffer zone.
• For more information on installing DITRA-HEAT-E-HK heating cables on 208 V circuits, please see page 25.
• Two DITRA-HEAT-E-HK heating cables can be connected and controlled by a single DITRA-HEAT-E-RT/-RSD/-R thermostat if the total current is less than 15 amps.
The heating cable leads must be wired in parallel according to applicable electrical and building codes.
• Multiple DITRA-HEAT-E-HK heating cables over 15 amps cannot be connected to a single DITRA-HEAT-E-RT/-RSD/-R thermostat. Additional DITRA-HEAT-E-RT/-RSD/-R
thermostats must be used or the DITRA-HEAT-E-RT thermostat may be combined with the DITRA-HEAT-E-RR power modules.