ThermalSheet Insulating Underlayment (2’ x 3’) - 6 Sq. Ft. - 1 Sheet

4.88
Based on 8 reviews
  • Single 2' x 3' sheet of synthetic cork insulating underlayment that functions as a thermal break
  • Heat and cold resistant, and will not rot, support mold and mildew, or absorb moisture
  • ThermalSheet has a 1.5 R-value, and it offers crack isolation of up to 1/4”
  • This lightweight insulating underlayment will increase the energy efficiency of your floor heating system
  • Can be used under a wide range of floor coverings like tile, stone, LVT, and laminate and can be used over any acceptable subfloor
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ThermalSheet Insulating Underlayment Description

ThermalSheet is a synthetic cork underlayment that is installed on top of a subfloor and below a heating element. It is recommended when installing an electric floor heating system over a concrete slab to prevent heat loss. By creating a thermal break, the heat is prevented from sinking into the concrete, and more heat radiates into the floor covering and room. In addition to preventing unnecessary heat loss, ThermalSheet provides sound dampening benefits and double the crack isolation benefits when compared to cork.

ThermalSheet is lightweight—up to 25 times lighter than traditional 1/4" backer board. This product is a 6 mm (less than 1/4 in.) thick, synthetic cork underlayment that can be installed with modified thinset and is specifically designed for setting tile and stone. It is an excellent insulation choice under our TempZone™ or Environ™ electric radiant floor-heating products. It’s a very resilient underlayment with compressive strength of 41 psi at 25% strain, 54 psi at 50% strain, and 110 psi at 75% strain. ThermalSheet has been rated for residential use according to the Robinson Test.

This item is a 2' x 3' (6 sq. ft.) single sheet. 

Specifications

Insulation Specification

Acoustic testing on 6" slab, no ceiling IIC 52 wood construction. FIIC 59 - 7.5″ concrete slab. ΔIIC 20 - 6″ concrete slab
Compressive Strength 41 psi at 25% strain, 54 psi at 50% strain, and 110 psi at 75% strain
Material Expanded Polypropylene (EPP)
Thermal Insulation 1.5 R-Value

Product Dimensions

Coverage 6 ft²
Depth 0.2362″
Length 36″
Weight 0.4 lbs
Width 24″

Identifiers

SKU TS-SH6MM-24x36
UPC (GTIN-12) 881308077037

Warranty / Certifications

TCNA Robinson test Residential
Warranty 5 years

Frequently Asked Questions

Please keep in mind that you must check your electric floor heating system with a digital ohmmeter in conjunction with a Circuit Check™. Take an initial reading as soon as you take the product out of the box to verify that it is within -5% / +10% of the values stated on the product’s label. This will give you a basis of comparison for future readings. Take a second reading once you have positioned the system to match your custom installation plan. It is also advisable to take an additional reading in the middle of the tile installation, just to make sure that the Circuit Check™ is doing its job. Then, take a final reading when you are finished with the floor installation and are ready to hook up the thermostat.

The Circuit Check™ is a tool developed by WarmlyYours to give you peace of mind and ensure trouble-free installations. Simply hook up the cold leads to the tool while you position the system to match your custom installation plan.

The Circuit Check™ will continuously monitor the continuity of the circuit during the installation of your system and during the installation of your flooring. The Circuit Check™ beeps immediately when a short in the system is detected, alerting you to a potentially damaged cable in the area you are working, before you lay the tile over the electric floor heating system.
 The WarmlyYours technical support team is available 24/7 to provide assistance if the alarm sounds, or if you would have any questions during your installation.

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When installing electric floor heating over a concrete slab, an insulating underlayment like ThermalSheet is highly recommended to ensure efficient operation, faster heating times and warmer floor temperatures.

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Insulating underlayments and uncoupling membranes share some key characteristics like providing crack isolation benefits, but they are separated by their primary functions.

Insulating underlayments, like WarmlyYours ThermalSheet, provide a thermal break between a subfloor and the heating elements, which can help prevent the concrete from acting as a “heat sink” and increase energy efficiency. ThermalSheet has a 1.5 R-value, and it offers crack isolation of up to ¼”. This can be particularly beneficial if you are trying to heat a room above a cement slab or above an unheated garage. 

Uncoupling membranes, like the Prodeso membrane, are great for protecting relatively fragile floor coverings like tile from foundational movement. They also allow for faster installation times than many other types of floor heating.

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No, an underlayment isn’t always necessary. 

However, there are some situations in which the use of an underlayment would be required, such as heating over a cement slab (where an insulating underlayment would most likely be required). When heating over a cement slab, our recommendation is to use ThermalSheet as your underlayment. 

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Typically, an uncoupling membrane like Prodeso will be best for this application because it can be paired with accessories to effectively waterproof the subfloor. 

However, if you have a cement subfloor, then ThermalSheet synthetic cork is a good choice because of its high 1.5 R-value and moisture resistance. 

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Customer Reviews