Installation Guide

ALTERNATIVE FLOOR COVERINGS 17
Engineered wood, vinyl, WPC/LVT/LVP, SPC tile/plank, and
laminate flooring over Schluter
®
-DITRA-HEAT
ALTERNATIVE FLOOR COVERINGS
This section summarizes the requirements, limitations, and general installation guidelines for installing alternative floor coverings over
Schluter
®
-DITRA-HEAT and Schluter
®
-DITRA-HEAT-DUO membranes and Schluter
®
-DITRA-HEAT-E-HK heating cables. It also explains
the limitations of these flooring materials when used over a floor warming substrate compared to ceramic and stone tile. Please use this
section in conjunction with the Schluter
®
-DITRA-HEAT Installation Handbook to help ensure a successful installation. Table 1 below lists
the various types of alternative floor coverings tested.
The Schluter DITRA-HEAT system was designed for use with ceramic, porcelain, and stone tile coverings. It is important to note the
alternative flooring materials have heat conductivities which are on average 10 times lower than those for ceramic, porcelain and stone.
Also, not all brands and products that fall into the alternative floor coverings types listed in Table 1 are compatible with radiant floor warming.
It is essential to read the floor covering data sheet, or installation instructions, or to verify directly with the manufacturer that
the chosen floor covering is compatible with radiant floor warming and that the temperature limit is at minimum 85°F (29.5°C).
Notes
1. The temperature values reported above are based on laboratory testing; they can serve as estimates of performance in the field, but cannot predict project-specific results.
2. Surface temperatures will vary with room temperature; those reported above are based on a thermostat set point of 82°F (28°C) and room temperature of 72°F (22°C).
3. Surface temperature ranges are reported because results will vary based on floor covering thickness and installation method.
4. For floating laminate flooring and engineered wood, the foam pad or mat used was 3/32" (2.4 mm) in thickness. Expected flooring surface temperatures will be lower with
thicker foam pads or mats.
* Most SPC flooring materials withstand higher sub-floor temperatures than 85°F (29.5°C), please consult with manufacturer's data sheet or installation instructions to determine
how high your choice can be set.
Floor Covering
Type
Thickness
Self-Leveler Min. Thickness
Over DITRA-HEAT
Membrane Studs
Expected
Average Surface
Temperature
1, 2, 3
(in) (mm) (in) (mm) (°F) (°C)
SPC (Vinyl-Based LVT/LVP &
1/8 – 9/32 3 – 7 0.25 6 80.5 – 79 27 – 26
Non Vinyl-Based Tile & Plank)*
Vinyl/WPC/LVT/LVP 1/16 – 5/16 1.5 – 8 0.25 6 80 – 77 26.5 – 25
Engineered Wood 3/8 – 9/16 10 – 15 0.25 6 77 – 76 25 – 24.5
(Adhered) 5/8 – 3/4 16 – 19 0.31 8 75 24
Laminate & Engineered Wood
9/32 – 19/32 7 – 15 0.25 6 77 – 76 25 – 24.5
(Floating)
4
Ceramic, Porcelain,
1/4 – 1/2 6 – 12.5 N/A N/A 82 28
and Stone Tile
Table 1: Expected Flooring Surface Temperatures and Thickness Requirements for Self-Leveling Underlayment
REQUIREMENTS AND LIMITATIONS
Schluter
®
-DITRA-HEAT is suitable for applications with engineered wood, vinyl, wood plastic composite (WPC), luxury vinyl tiles (LVT),
luxury vinyl planks (LVP), stone plastic composite (SPC) tiles and planks, and laminate flooring, subject to the following requirements and
limitations:
Verify with the floor covering manufacturer that the selected product is
suitable for radiant floor warming applications and that it can
withstand a temperature of 85°F (29.5°C) at minimum.
If floor covering to be used in a wet area, verify with the floor covering
manufacturer that the selected product is suitable.
The floor covering, including any foam/rubber pad or mat must not
exceed a thermal insulation value of R1 (Rsi of 0.18). All floor
coverings listed in Table 1 have a R-value below 1.
Carpets are generally not recommended, but if installed, they must not
exceed a R-value of 1, including any rubber pad or mat used.
Any floor covering adhesive must be recommended by the manufacturer,
suitable for use over a cementitious substrate, and compatible with
radiant floor warming.
A cementitious self-leveling underlayment is used to fill the
membrane and encapsulate the heating cables. Verify with the
underlayment manufacturer that it is suitable for the application. The
underlayment is applied to a level above the studs in the membrane as
specified in Table 1, according to the type and thickness of the floor
covering. The underlayment should be applied in a single pour.
Any floor leveling must be done prior to the DITRA-HEAT system
installation. Thicker than necessary, or uneven thickness of self-leveling
underlayment above the DITRA-HEAT system will affect performance.
The thermostat must be set at 82°F (28°C) or lower at all times.
This can be done manually or by selecting “Laminate Flooring” in the
“Floor Protection” section of the “Installer Settings” menu of any of the
Schluter
®
-DITRA-HEAT-E thermostats.
If the floor covering is SPC type, the thermostat set point could be set
higher, but verify the limit with the manufacturer's data sheet or installation
instructions.
Solid hardwood is not recommended in floor warming applications due
to its thickness and risk of damage caused by excessive drying of the
wood while exposed to heat.