When to Use Under Concrete Insulation

Published on: Feb 24 2016 by EcoFoil

Sean Waters, Product Specialist

I receive many questions from customers about using our radiant barrier products to increase efficiency in their slab. Concrete floors have a reputation for being cold, and it’s true that concrete has a lower insulation value than most other building materials.  Many times there is a bit of confusion as to which product works best to battle these cold floors.  Fortunately, our under concrete slab insulation is designed specifically for this purpose.

Under slab insulation

Under Concrete Insulation


Some questions I hear regularly are, “What is the difference between bubble insulation  and under concrete insulation?” And “Can’t I just use the bubble insulation under the concrete?”  The bubble insulation is designed differently with a metallic foil radiant barrier on the outside of one or two layers of polyethylene bubbles, while the under concrete radiant barrier has a patented design with the metallic foil radiant barrier in the center of two polyethylene bubbles. This is important because aluminum and concrete don’t play well together; there is an adverse chemical reaction when the aluminum in the foil comes in contact with the lime in the concrete. In fresh concrete, bubbles will form on the surface as the concrete cures. Foil will not damage cured concrete, but the concrete will cause the foil to corrode which will greatly reduce its effectiveness.


EcoFoil’s under concrete insulation- also sometimes called under slab insulation- has a layer of reflective foil sandwiched between two layers of polyethylene bubbles. These bubbles protect the foil from the corrosive properties of the concrete while simultaneously stopping heat transfer through conduction.


The first response I usually get is “Won’t those bubble pop?” The answer is “NO.” Our concrete slab insulation is specifically designed to handle the abuse during construction and withstand the weight of the slab. With a compression strength of 140psi and a puncture resistance of 85 lbs/sq. in, it’s virtually indestructible. The regular bubble insulation does not have the compression strength or puncture resistance.



This product works great with in-slab radiant heated floors as well as creates a 100% vapor barrier when using our 3” white insulation tape to seal off the seams. With both sides of the product being the same, installation is virtually foolproof. The patented design isolates the foil from the concrete and from the humid conditions below the slab increasing the effectiveness and lengthens the life of the foil.


ef4All of these great benefits make our under concrete insulation ideal for alternative uses as well.  We’ve had customers share their experiences of using it in horse watering systems, portable living structures known as yurts, and underneath in-ground swimming pools.  Have you used insulation for an alternative use?  Let us know, we’d love to hear about it and share it with our readers. Send your story to: CustomerService@EcoFoil.com. For all questions and order call us at 888-349-3645 or go to www.ecofoil.com.

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