ThermalSheet Insulating Underlayment (2’ x 3’) - 6 Sq. Ft. - 1 Sheet
Features
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Single 2' x 3' sheet of synthetic cork insulating underlayment that functions as a thermal break
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Heat and cold resistant, and will not rot, support mold and mildew, or absorb moisture
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ThermalSheet has a 1.5 R-value, and it offers crack isolation of up to 1/4”
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This lightweight insulating underlayment will increase the energy efficiency of your floor heating system
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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.
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 |
Logistics
| Country of Origin (COO) | United States of America |
Product Dimensions
| Coverage | 6 ft² |
| Depth | 0.2362″ |
| Length | 36″ |
| Width | 24″ |
Identifiers
| SKU | TS-SH6MM-24x36 |
| UPC (GTIN-12) | 881308077037 |
Warranty / Certifications
| TCNA Robinson test | Residential |
| Warranty | 5 years |
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.
How many square feet of floor heating can be connected to one thermostat?
One thermostat can control multiple heating mats/cables as long as all the heating elements are using less than 15 amps:
TempZone™ will cover aprx. 120 sq. ft. for 120V systems and 240 sq. ft. for 240V systems on one thermostat.
Environ™ will cover aprx. 150 sq. ft. for 120V systems and 300 sq. ft. for 240V systems on one thermostat.
Slab Heat will cover aprx. 90 sq. ft. for 120V systems and 180 sq. ft. for 240V systems on one thermostat.
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.
View all 10 Questions and Answers
Customer Reviews
ThermalSheet Insulating Underlayment achieved an average rating of 4.5 stars with 2 reviews by our customers.
It’s not the same thickness as original version
Lanny M., Slave Lake, AB on 05/12/2024
We had ordered the original version of this product and our project got delayed. When we went to finally complete the floor, we found we needed more. We could not find the exact same item we originally ordered so ordered this instead and the specs showed the thickness as the same. When it arrived and we installed it, we found it was slightly thicker. If a person was using tile, it wouldn’t have been an issue as the thinset would have evened it out. As we were using laminate vinyl tile, we had to use a self leveling mixture first before we could put our flooring down. Just something to watch out for.
Good product, Easy to install
Jon B., Lansing, NY on 03/07/2024
The Thermalsheets were exactly as described, easy to cut and install on the floor, and really helped keep out the cold.