How to Guide

Membrane is selected according to the size of the area to be tiled.
Heating cable is selected according to the size of the area to be heated. Be sure to measure the heated area accurately. The allowable heated area
is limited by the minimum required spacing from fixed elements such as:
Select a heating cable closest to, but not exceeding the total area determined in Step 3 below. Do not select a heating cable according to the size
of the area to be tiled; this will be too much heating cable. Only select a heating cable according to the size of the area to be heated, and to your
choice of cable spacing depending upon the specific application.
It is helpful to plan the location of a buffer zone. The buffer zone is an area where heating is not essential and heating cable installation is not
planned. This area allows for placement of excess heating cable. When using 3 stud cable spacing, any additional excess heating cable may be
used up by utilizing the continuously alternating 3-2 stud cable spacing at locations where more heat may be desired.
Using Multiple Cables
Multiple DITRA-HEAT-E-HK heating cables can be connected in parallel and controlled by a single DITRA-HEAT-E thermostat if the total current is less than 15 amps. Depending on
your applicable electrical and building codes, this work may need to be performed by a qualified electrician.
Multiple DITRA-HEAT-E-HK heating cables over 15 amps cannot be connected to a single DITRA-HEAT-E thermostat. Additional DITRA-HEAT-E thermostats must be used or the
DITRA-HEAT-E may be combined with the DITRA-HEAT-E-RR power modules.
IMPORTANT: HEATING CABLES CANNOT BE CUT TO FIT
Never install the heating cable under vanities with no air space beneath, bathtub platforms, free standing bathtubs with no air space beneath, kitchen cabinets or any other fixtures,
or in storage or clothing closets. Excessive heat will build up in these confined spaces and may cause cable overheating.
For additional information, please see the DITRA-HEAT Installation Handbook.
Step 1 - Draw room
Step 2 - Calculate membrane required
Step 3 - Calculate cable size(s)
Draw the room floor plan on the other side of this sheet.
Measure areas where the membrane will be installed. The total will tell you how much DITRA-HEAT or DITRA-HEAT-DUO membrane is required.
Measure areas where the heating cable is to be installed. The total tells you the maximum DITRA-HEAT-E-HK heating cable amount. Remember to account for required
clearances: walls, partitions, and fixed cabinets is 2"; plumbing drains is 4"; heat sources is 8"; centerline of toilet drains is 7"
Schluter
®
-DITRA-HEAT Calculation Sheet
Both membrane and cables need to be calculated. Follow the steps:
DITRA-HEAT or DITRA-HEAT-DUO
Membrane
DITRA-HEAT-E-HK
Heating Cable
64"
48"
72"
77"
A
1
A
2
25"
28"
45"
24"
72"
2" clearance
15"
68"48"
B
1
B
2
B
3
B
4
Buffer
zone
Example
Example
Area Dimensions Total
A
1
64" x 48" 3072 in
2
A
2
77" x 72" 5544 in
2
A
3
- -
A
4
- -
Divide total by 144 to get measurement in ft
2
8616 in
2
÷ 144
Grand Total Membrane 59.8 ft
2
Area Dimensions Total
B
1
15" x 48" 720 in
2
B
2
28" x 68" 1904 in
2
B
3
45" x 72" 3240 in
2
B
4
25" x 24" 600 in
2
Divide total by 144 to get measurement in ft
2
6464 in
2
÷ 144
Grand Total Heating Cable 44.9 ft
2
Try the Calculation Sheet…
or Download our App with
DITRA-HEAT Estimator!
scan here
• Walls, partitions, and fixed cabinets = 2" (50 mm)
• Plumbing drains and forced air heating vents = 4" (100 mm)
• Heat sources (baseboard heaters and other fixed heating
devices, fireplaces, etc.) = 8" (200 mm)
• Centerline of toilet drains = 7" (180 mm)
NOTE: This is a typical estimation for the installation of ceramic and stone tile.
For applications using alternative floor coverings, please refer to the AFC bulletin on Schluter.com
When choosing the appropriate heating cable(s)
size(s), please consider whether you require 3 stud
cable spacing or alternating 3-2 stud cable spacing.