ThermalSheet Insulating Underlayment (2’ x 3’) - 6 Sq. Ft. - 1 Sheet
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
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.
|Acoustic testing on 6" slab, no ceiling
|IIC 52 wood construction. FIIC 59 - 7.5″ concrete slab. ΔIIC 20 - 6″ concrete slab
|41 psi at 25% strain, 54 psi at 50% strain, and 110 psi at 75% strain
|Expanded Polypropylene (EPP)
|Country of Origin (COO)
|United States of America
Warranty / Certifications
|TCNA Robinson test
Documents & Manuals
Customer Questions & Answers
ThermalSheet Insulating Underlayment has 10 Questions and Answers.
Should I add insulation before installing electric floor heating and how will that affect the system's performance?
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.
Is a floor heating underlayment always required?
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.
How are insulating underlayments different from uncoupling membranes?
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.
Which floor heating underlayment is best for a high-moisture installation like a bathroom?
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.
Do I need to adhere the ThermalSheet underlayment to the subfloor when installing an Environ heating system with a floating floor, such as laminate?
No, ThermalSheet underlayment floats over the subfloor, adjacent sheets are staggered and taped together to prevent any overlapping.
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