Low-E in Concrete Pad/Basement Floor

Low-E Slab Shield is a trade name for ESP Inc's underslab concrete insulation. Slab Shield is intended to be used as a vapor barrier in concrete applications where a vapor barrier and R-Value is needed. Slab Shield is not intended to be used on walls, attics or any other place where fire or flame may come in contact with the product.

Please consult your local codes for proper placement of your concrete vapor barrier.

The best time to install Low-E Slab Shield is:

  • After site has been leveled, compacted and set to grade
  • After all under slab plumbing, sewage and electrical has been installed
  • After all concrete column and pillar forms have been installed
  • Before any rebar, road wire or other type of steel reinforcing
  • Before radiant heating tubes

Advantages to Using Low-E Slab Shield

  • Easy Installation
  • Vapor Barrier
  • Thermal-Break Reduces Cracks in Concrete
  • Acts as a Dual Layer Termite Shield Under Concrete
  • Reduces Concrete Dry Time and in Turn Reduces Labor
  • Creates a Cushion for Installer While Adding Reinforcing Steel
  • Separates Ground from Building Temperature
  • Withstands Punctures When Walking On and Installing Reinforcing Steel
  • Creates a Cushion Under Concrete Minimizing Cracks in Concrete Slab
  • Helps Eliminate Ground Moisture Entering Building Through Slab<

Let's Compare Low-E Slab Shield to Visqueen Plastic

Many people install up to 10 mil thick Plastic, or Visqueen. Visqueen is made from low grade resins, most Visqueen does not even comply with a permeance rating of 0.10 required by many Engineers and Architects. During installation, Visqueen is walked on creating holes in the plastic, then punctured with the steel reinforcing. This will cause it to deteriorate in time. It's a waste of time and money placing a low grade vapor retarder under a slab expecting it to last and work like a vapor barrier should.

Slab Shield is made from 2 layers of polyethylene heat laminated to a center layer of foil. The permeance rating is 0.002 which is much better than Architects and Engineers require. Slab Shield is not a vapor retarder like many plastics; it is a true vapor barrier. While walking on Slab Shield, it not only custions your step, most rocks will not penetrate the 2 layers of polyethylene foam. Slab Shield has a bursting strength of 92.9 psi which makes it strong enough to hold up to most construction practices.

As an added bonus it has a layer of aluminum foil. The foil is sandwiched between two layers of foam to help protect the foil from any lime it may come in contact with. The dual action system helps restrict heat from leaving your building and keeps the cool moist ground temperature from cooling your freshly poured concrete. This allows the heat from the concrete to cure your concrete faster saving time and labor on your concrete pour. Another added bonus Slab Shield has a tested R-Value of 2.9.

A difference between Slab Shield and foam boards is its ability to mold itself to the contours of your grade. Slab Shield is flexible enough to adjust to the high and low areas helping to create a stronger finished concrete pour. Slab Shield also does not crack or crumble when faced with the normal abuses the job site throws at it.

Three Forms of Ground Moisture

In it's liquid or vapor form ground water can enter through your concrete slab and cause extensive damage to personal property by three forms of migration.

Hydrostatic Pressure:
Water pressure created from water table.

Capillary Action:
The ability of liquid to move upward through a material due to the adhesive and cohesive properties of a liquid and barometric pressure.

Vapor Migration:
The movement of vapor from a high humidity environment to a low humidity environment through the process of diffusion. The amount of vapor transferred is directly related to the pressure between the two environments.

Why use a Vapor Barrier?

According to HUD, a slab building which does not have an adequate moisture protection system, up to 80% of the moisture withing the building originates from ground water.

Many experts in the construction industry feel a good vapor barrier must be used under concrete slabs, heated or unheated in order to prevent moisture infultration through the slab. The moisture has been known to cause:

  • Poor indoor air quality health issues, due to the creation of mold, mildew and fungus
  • Damage to the slab and its components
  • Increased building heating costs due to high humidity levels caused by moisture from the slab
  • Damage to building contents due to high moisture levels
  • Increased moisture in floor covering causing premature floor system failures

All of the problems from the vapor movement in a concrete slab will go away as the slab dries, as long as there is no source of additional water going into the slab. The most common source of moisture is from the ground beneath the slab. In order to fix this, you have to stop the ground vapor from entering the slab. The best way to accomplish that is with an under concrete vapor barrier.

Vapor retarders have been used for years. Recently, though, research has shown us that the old tradition layer of Visqueen under the slab is not very effective for two main reasons:

  • Even though we think it is water tight a lot of vapor can pass through this product.
  • Plastic gets damaged while placing reinforcing steel and concrete, creating holes which allow large amounts of vapor into the building.

Slab Shield vapor barrier does not allow water vapor to penetrate into the slab. Vapor retarders only slow down the vapor but will not stop it. Slab Shield has a permeance of 0.002 and completely eliminates moisture migration from going through the concrete slab which allows it to dry out quickly and stay dry.