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

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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No, ThermalSheet underlayment floats over the subfloor, adjacent sheets are staggered and taped together to prevent any overlapping.

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Any type of underlayment/padding may be used as long as it has a density of 6-8 pounds per cubic foot. Certain underlayment, such as ¼” (6mm) thick cork, or 6mm ThermalSheet are recommended for Environ™ Flex Rolls. It is also acceptable to place a vapor barrier, such as a plastic sheet, under the underlayment. Underlayment papers are not compatible with Environ™ Flex Rolls. Underlayment is necessary to prevent Environ™ Flex Rolls from damage from the weight of the floor, furniture, and people. Unavoidable wooden floor movements will not harm Environ™ Flex Rolls. Wooden floors expand and contract with temperature and moisture change. The wooden floor “moves” on top of Environ™ Flex Rolls. This movement will not damage Environ™ Flex Rolls when the installation is done correctly and the underside of the final floor covering is installed evenly. Some underlayment materials also have a noise reducing and insulating effect. When installing over concrete, a ¼” underlayment is mandatory. Any underlayment available in ¼” size is acceptable in most cases. ThermalSheet, cork, or ¼” to 3/8” of expanded polystyrene (EPS) with a density of 2 pounds per cubic foot or more, are recommended for installation under Environ™ Flex Rolls. When installing over a concrete slab, choose the underlayment with the highest R-Value.

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ThermalSheet Insulating Underlayment is a synthetic cork, a lightweight thermal barrier made of hemi-crystalline thermoplastic.

WarmlyYours recommends ThermalSheet underlayment when installing a floor heating system over a concrete slab to prevent heat loss and protect against moisture. It will not rot, support mold and mildew, or absorb moisture.

- ThermalSheet synthetic cork underlayment (6mm) has a 1.5 R-value, crack isolation up to 1/4“, reduces sound by up to 22 dB, and is Robinson tested (TCNA) and rated for residential loads.

- Cork (6mm) has a .72 R-value, crack isolation up to 1/32“, reduces sound by up to 23 dB, and is Robinson tested (TCNA) and rated for residential loads.

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No. Put a skim coat of SLC (Self-Leveling Cement), or even plywood over it first. Then, the vinyl flooring product can be installed.

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Yes, all pressure-sensitive adhesives are fine.

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Yes, ThermalSheet should be bonded to the subfloor with any high quality modified thin-set, or with a bond coat adhesive. Further installation information can be found in the installation manual. 

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Yes, unlike natural cork, ThermalSheet will not expand from self leveling cement (SLC).

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