Insul-Tarp Technical Product Information

Insul-Tarp® Insulation Materials and Construction

Insul-Tarp in-slab insulation features a unique design and construction that includes the following top-quality materials:

  ●  Cross-woven polyethylene for rugged durability

  ●  High-density closed-cell foam

  ●  High-density polyethylene bubble

  ●  Two layers of reflective aluminum

Physical Properties of Insul-Tarp Ground Insulation
Property Test Method Insul-Tarp
Average Thermal Resistance ASTM C 518 R - 7.5
Tensile Strength and Elongation*
ASTM D 412 136 PSI
Tensile Strength** ASTM D 751 45lbs-f/in.
Compression Set ASTM D 3575 4.3 %
Bursting Strength* ASTM D 751-73 90 PSI
Maximum Use Temperature 180°F
Minimum Use Temperature -60°F
Water Vapor Permeance ASTM E 96 .002 Perms

  * Denotes testing on bubble pack only

  ** Denotes testing on cross woven polyethylene only

Insul-Tarp in-slab insulation attached to wire mesh under radiant floor heating element.

Tested R Value (R-7.5)

Insul-Tarp was tested in accordance with ASTM C 518, Standard Test Method for Steady-State Heat Flux Measurements and Thermal Transmission Properties by Means of the Heat Flow Meter Apparatus. See the Non-Radiant Testing PDF in the table below for a detailed summary of the testing procedure and results.

Performance Equivalent: R-10 (Under Radiant Heating Systems)

When calculating heat loads for radiant heating systems, a performance equivalent of R-10 can be used. Although this is not a tested R-value, field and laboratory tests support this number as a reasonable gauge for measuring performance. The Lab Test 1 and Lab Test 2 PDFs in the table below illustrate Insul-Tarp's radiant heating performance.

Insul-Tarp Specifications and Test Result Documentation

Insul-Tarp Product Documentation

»  Insul-Tarp Installation Guide

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»  Insul-Tarp Product Specifications

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»  Insul-Tarp vs. Bubble Foil and Foam Board

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»  Insul-Tarp vs. Bubble Foil Test

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»  Non-Radiant Test Data Sheet


»  Insul-Tarp Lab Test 2

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»  Click here to Download Adobe Reader.

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A roll of Insul-Tarp Insulation.


"The absolutely incredible thing about Insul-Tarp was the performance during heat up times of the slab. Projects done with 2-inch polystyrene seem to take up to 30 percent longer to get up to temperature. This product works better than any other product we have tried."

  – Michael W., Hi Valley Supply

"When compared to the cost of styrofoam and the cost of installing and cutting styrofoam, it is much more cost efficient to use Insul-Tarp."

  – Carlo S., United Plumbing

Insul-Tarp under slab insulation may be the easiest ground insulation to install and the most effective. For more information about Insul-Tarp or radiant floor heating, snow melting or roof de-icing solutions, call Warmzone today at 888.488.9276.