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Insul-Tarp Technical Product Information

Insul-Tarp® Insulation Materials and Construction

Insul-Tarp in-slab insulation is constructed of features a unique 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

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
»  Non-Radiant Testing
»  Insul-Tarp Installation Guide
»  Insul-Tarp Product Specifications
»  Insul-Tarp Test Data Sheet
»  Insul-Tarp Lab Test 1   
»  Insul-Tarp Lab Test 2   

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Under-slab Insulation

Insul-Tarp ground insulation under radiant heating cables.

Insul-Tarp under slab insulation is the easiest ground insulation to install and the most effective. The picture above shows Insul-Tarp in-slab insulation installed under radiant floor heating cable attached to wire mesh.


"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