Installation Guide

18 ALTERNATIVE FLOOR COVERINGS
INSTALLATION
The following installation method has been developed and evaluated through a series of tests to ensure practicality and successful
results. This information below is meant to provide the highlights of a typical installation. Please refer to detail DH-AFC and the Schluter
®
-
DITRA-HEAT Installation Handbook for complete installation guidelines.
1. Provide perimeter joints at the outer edges of the installation to
accommodate movement due to changes in moisture, temperature, and
loading. Sill seal (a polyethylene foam gasket) is an effective quality control
measure to provide perimeter movement joints.
2. Install the DITRA-HEAT or DITRA-HEAT DUO membrane using thin-set
mortar.
3. Test the DITRA-HEAT heating cable(s) prior to installation.
4. Embed the heating cables between studs at continuously alternating
3-2 stud spacing.
5. Install the tip of each floor temperature sensor in the middle of a 2
stud cable spacing section, instead of a 3 stud cable spacing section.
6. Retest the heating cable(s) to verify no damage occurred during the
installation.
7. Fill the membrane and encapsulate the cables with a cementitious self-
leveling underlayment. Apply the underlayment to a level according to
Table 1.
8. Once the self-leveling underlayment has set, retest the heating cable(s) to
verify no damage occurred during the installation.
9. Allow the self-leveling underlayment to cure according to the underlayment
and floor covering manufacturers’ instructions prior to the installation of
the floor covering.
10. Install the floor covering according to the manufacturer’s instructions.
11. Install the DITRA-HEAT-E thermostat in the electrical junction box,
connecting it to the heating cable cold lead and to the electrical power
supply.
12. Start up the floor warming after any waiting period required by the self-
leveling underlayment and floor covering manufacturers.
13. The thermostat must be set to “Laminate Flooring” in the “Floor
Protection” section, and to “Floor” in the “Sensor Application”
section, both in the “Installer Settings” menu. The set point
temperature of the thermostat must remain at 82°F (28°C) or below at
all times, unless the floor covering is a SPC type. If an SPC type, verify
with manufacturer's data sheet or installation instructions if the set point
temperature can be raised to a higher level.
Floors, Interior - Engineered Wood, Vinyl,
WPC, LVT/LVP, SPC, and Laminate
DH-AFC-20
Engineered Wood, Vinyl, WPC, LVT/LVP,
SPC, and Laminate
Floor covering adhesive
or foam underlayment,
if required, per manufacturer
Cementitious self-leveling
underlayment
DITRA-HEAT
or DITRA-HEAT-DUO
uncoupling membrane
and heating cables
Thin-set mortar
per appropriate
detail
Alternative Floor Coverings
Areas of Application
over any even and structurally sound
substrate
interior dry or wet areas (verify suitability of
floor covering material for wet areas)
Limitations
DITRA-HEAT-DUO not recommended over
hydronic heated floors
withstand temperature for floor covering:
85°F (29.5°C) or greater
maximum thermostat set point 82°F (28°C)
in service, unless floor covering is SPC type
and can withstand a higher temperature
maximum thermal insulation of floor
covering R1
moisture-sensitive floor coverings not
recommended for wet areas
Requirements
floor covering must be recommended for
the application by the manufacturer
DITRA-HEAT-E-HK heating cables spaced
at continuously alternating 3-2 stud pattern
floor temperature sensors must be placed
between heating cables spaced at 2 studs
minimum self-leveling underlayment
elevation over studs 1/4" (6 mm) or 5/16" (8
mm), as per Table 1
Substrate Preparation
in accordance with applicable DITRA-HEAT
Installation Handbook detail and floor
covering manufacturer’s directions
any leveling of the subfloor must be done
prior to installing DITRA-HEAT and DITRA-
HEAT-DUO
Movement Joints
DITRA-HEAT and DITRA-HEAT-DUO do not
eliminate the need for movement joints,
including perimeter joints. Movement joints
must be installed in accordance with
industry standards and floor covering
manufacturer’s directions
Setting Materials
unmodified thin-set mortar – ANSI A118.1
modified thin-set mortar – ANSI A118.11
cementitious self-leveling underlayment –
recommended by SLU manufacturer
Installation Specifications
cementitious self-leveling underlayment –
ASTM F2873 and manufacturer’s directions
floor covering – follow manufacturer’s
directions
Other Considerations
alternative floor coverings have lower
thermal conductivity than ceramic and
stone tile and surface temperatures will be
lower in these applications at the same
thermostat set point; this effect is magnified
as the alternative floor covering thickness is
increased
where a waterproof floor is required, all
DITRA-HEAT and DITRA-HEAT-DUO seams
and floor/wall transitions must be sealed
with KERDI-BAND using Schluter SET
®
,
Schluter ALL-SET
®
, Schluter FAST-SET
®
, or
unmodified thin-set mortar; see DH-WP in
the DITRA-HEAT Installation Handbook
vapor barrier on crawl space floors
according to regional building codes