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.
• 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. 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 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. 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 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.
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
• Select DITRA-HEAT 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 or fixtures = 3" (75 mm)
• Heat sources (baseboard heaters, fireplaces, forced air heating ducts, etc.) = 8" (200 mm)
• Floor Drains = 6" (150 mm)
• Two or more DITRA-HEAT-E-HK heating cables can be connected and controlled by a single DITRA-HEAT-E-RS thermostat if the total current is less than 16 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 16 amps cannot be connected to a single DITRA-HEAT-E-RS thermostat. Additional DITRA-HEAT-E-RS thermostats must be
used or a control system comprised of relays and low voltage thermostats may be substituted (if the heating cables are in one room). The system must still incorporate a floor
temperature sensor and the circuit must be protected by a GFCI.