Cork Insulating Underlayment (24″ x 36″ x 6mm) Pack of 4 Sheets

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.

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

Yes, radiant floor heating can be a primary heat source if its heat output exceeds the room's heat loss. For best results, we recommend using a 15-watt system, covering at least 80% of the floor, and ensuring the space is well-insulated. Use our Heat Loss Calculator to verify your specific needs.

Yes, radiant floor heating is an excellent primary heat source for tiny houses in mild to moderate climates. Because tiny houses have small footprints, the 15-watt output of TempZone™ can easily maintain comfort while saving valuable wall space. Ensure the structure is well-insulated and use our Heat Loss Calculator to confirm.

Yes, we strongly recommend installing insulation like ThermalSheet™ over concrete slabs. Concrete acts as a "heat sink," absorbing warmth that should go to your floor. Insulation directs the heat upward, significantly improving efficiency, reducing warm-up times, and allowing the system to function effectively as a primary heat source.

Underlayment is recommended for floating floors (laminate, LVP, wood) and installations over cold subfloors like concrete. It provides thermal insulation to prevent heat loss and improves system efficiency. For tile and stone, the system is typically embedded in thinset, so a separate underlayment is often unnecessary.

WarmlyYours TempZone™ Flex Rolls and Easy Mats deliver 15 watts per square foot, the maximum allowed by the National Electrical Code. This provides 25% more heating power than the 12-watt industry standard. TempZone™ Cable can be spaced to deliver between 8 and 15 watts per square foot depending on your needs.

Yes, electric radiant floor heating is ideal for basements because it warms the cold concrete slab and provides consistent heat from the ground up. In well-insulated finished basements, it can serve as the primary heat source, turning a typically chilly space into a comfortable, year-round living area.

Radiant floor heating can heat a sunroom if the space has high-quality insulation and double-pane glass. Since sunrooms have high heat loss, a 15-watt system is essential. In extremely cold climates or poorly insulated sunrooms, it is best used as a supplemental source to keep the floor comfortable.

Yes, radiant heating is highly efficient in cold weather. Unlike forced-air systems that lose heat through ductwork and rising air, radiant heat warms objects directly via far-infrared energy. This method is up to 45% more energy-efficient, providing consistent comfort while significantly lowering monthly heating costs in frigid environments.