Installation Guide

24 DITRA-HEAT-TB
Solution to improve floor warming response time
DITRA-HEAT-TB
The challenge of concrete substrates
Concrete substrates can absorb enough heat energy to significantly increase the time it takes for floors to warm up, particularly when there
is no insulation layer below the concrete. In some cases, floors may never reach the desired temperature. There are solutions to address
this challenge, such as installing the heating cables at closer spacing for increased energy output or installing a thermal break prior to
heating cable installation to reduce heat loss into the substrate. However, both of these solutions increase material and labor costs.
A one-step solution
Schluter
®
-DITRA-HEAT-TB offers the same functions as the Schluter
®
-DITRA-HEAT membrane, but also features an integrated thermal
break in the form of a thicker bonding fleece. The thermal break reduces heat loss to the substrate and improves the floor warming
response time at the standard three stud cable spacing. Since an effective thermal break can be created with a relatively low R-value, the
DITRA-HEAT-TB membrane is only 5/16" (8 mm)-thick, compared to DITRA-HEAT at 1/4" (5.5 mm)-thick.
Thermal resistance
The DITRA-HEAT-TB thermal break was tested according to the ASTM C518 “Standard Test Method for Steady-State Thermal Transmission
Properties by Means of the Heat Flow Meter Apparatus” and determined to have an R-value of 0.35. This value may seem low, but it is
sufficient to improve the system warm up time. Increased thermal resistance may be required if improving overall energy efficiency is also
desired and the floor warming system is to be used for extended periods instead of limited hours during the morning and at night.
Floor warming performance
In laboratory testing, DITRA-HEAT-TB reduced floor warming response time from 68°F (20°C) to 78°F (25.5°C) by approximately 80% (90
minutes) compared to DITRA-HEAT over a concrete substrate.
Wood substrates act as insulators and typically do not pose the same challenges as concrete substrates. In the same laboratory testing,
DITRA-HEAT-TB only reduced floor warming response time from 68°F (20°C) to 78°F (25.5°C) by approximately 20% (5 minutes) compared
to DITRA-HEAT over a plywood substrate.
Schluter
®
-DITRA-HEAT-E-HK heating cables were spaced at three studs in all of the above tests.
Results above are based upon laboratory testing. Actual results may vary depending on various factors, including concrete substrate
thickness, concrete substrate temperature, room temperature, heat losses, etc.
0 010 1020 2030 3040 4050 5060 60
67.0
68.0
73.0
78.0
83.0
88.0
93.0
69.0
71.0
73.0
73.0
77.0
79.0
81.0
83.0
85.0
70 7080 8090 90100 100120 120110 110
Time (minutes) Time (minutes)
Temperature (ºF) Temperature (ºF)
DITRA-HEAT
DITRA-HEAT-TB
DITRA-HEAT
DITRA-HEAT-TB
Figure 1 - DITRA-HEAT-TB Performance over Concrete Figure 2 - DITRA-HEAT-TB Performance over Wood