Facts About EPS and Water Absorption

By: Doug Wehrwein, Sales Representative

Extensive testing has confirmed that the closed-cell structure of EPS reduces moisture absorption over prolonged periods. Even when moisture absorption has reached the maximum threshold there is minimal effect on the thermal performance of EPS insulation. When you review the Expanded Polystyrene Industry Alliance Technical Bulletin 103 you’ll see that even when the moisture absorption level reached 4.8% the EPS insulation’s R value was still at 94% of what was expected. Conversely, the R-value of a comparable sample of XPS was only at 52% of what was expected and moisture level of the XPS sample was 18.9%.

The area in which water can migrate into in the EPS material is the tiny channels (or the interstitial space) between the fused beads of expanded polystyrene. These channels naturally exist in EPS rigid insulations boards and serve as the means to easily release the water when drying occurs. Moisture is present in the EPS long enough for adverse effects to take place. When XPS is exposed to bulk moisture repeatedly over long periods it may allow water in, where it them becomes trapped. See Expanded Polystyrene Industry Alliance Technical Bulletin 104 and 105. Generally, neither water nor water vapors affect the properties of EPS.

Foam-Control Plus+® Architectural EPS Insulation is a very cost-effective way to provide both superior thermal resistance and protection for underlying foundation moisture protection systems.

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Summer time, need to ship wine?

By: Bryan Buchanan, Packaging Specialist

1673DuraTherm® wine shippers is a great packaging solution for shipping your wine from summer through the winter months. It is designed to resolve any issues with shipping a temperature sensitive product safely when the outside temperature is high; in addition to ensuring that it travels from point A to point B without breakage. Our design, with input from industry leaders, distributors, and freight carriers has helped to make this a solid and dependable program. DuraTherm® wine shippers have passed the rigorous ISTA 7E Summer Profile test. Is has also received ISTA 3A drop test certification, which confirms that your product is shipped in a package that will avoid content damage. Passing these critical tests provides our customers with peace of mind that their product is in good hands!

The summer DuraTherm® shipper comes in a 2-Pack, 6-Pack, and 12-Pack versions. We can provide the specially designed EPS foam in a corrugated box with designated gel packs as a complete kit.  Over the years we collected valuable customer input and have modified the summer shipper to create an unparalleled quality product with unique features for your valuable wine contents.

For more information on this product category please go to www.achfoam.com.

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Does EPS Bead Size Really Matter?

By: Joe Kurz, Packaging Specialist

EPS Bead and PennyAs the nations  2nd largest processor of expanded polystyrene bead, ACH Foam Technologies runs many different beads sizes through its facilities. These sizes vary depending on the intended usage.

While our Lost Foam operations in Fond du Lac, Wisconsin requires a very small bead in order to properly fill the detail areas of the molds used for this application, larger size beads are favored for production of billets used in our fabrication processes. Many variables come into play here, and our production experts at the plant level are the most knowledgeable about choosing the proper size bead for your intended use. Feedback from our customers, some of whom use our billets to create their products, is also very helpful in dialing in the proper recipe for their needs. One such customer will first hotwire our foam, and then mills it using a CNC router system. We supply them with billets in a “C” sized bead, which satisfies both processing methods perfectly. Another customer, one that cuts shapes and flat sheets, prefers a billet made with a mix of “B” and “C” size beads.

When a new customer comes to us for quotes, our trained, experienced sales and estimators know the proper questions to ask regarding how our EPS foam will be used. Armed with these answers, we can offer the correct product the first time, and ensure customer satisfaction. ACH Foam Technologies strives to continue to be the leader in EPS industry.

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The Performance and Sticker Price (R-Value) of EPS Insulation Ensures a Consistent Long-Lasting Positive Experience

By: John Myers, Sales Representative – Architectural Products

Wait a minute! You mean the published R-Value is not always an accurate reflection of the actual performance I will receive? How does that happen?

The reality of published R-Values for rigid foam insulation is somewhat like the estimated fuel mileage on the sticker of your new car. Rarely is it an accurate reflection of your actual mileage. Driving conditions, your lead foot, and other real life conditions will have an effect on your car. As will the quality of the fuel you put in your tank.

In the world of rigid insulation, the factors to consider are as simple as the method of production. First to consider is that all foam insulation boards are made from a type of plastic. The raw material is expanded into blocks then cut into sheets OR extruded into sheets. When the production process requires the use of gasses to extrude a raw material, the initial R-Values of the finished product can be overstated. The gas that is used for expansion is not permanent, and is eventually replaced with atmospheric air that rem

So when do we measure the R-Value? Just like the auto industry, the R-Value is calculated at the best possible condition, and in the case of rigid insulation it is at the time of manufacture. This is not always the R-Value you can expect to receive in the field, as verified by outside entities such as the National Roofing Contractors Association and Building Science to name a couple.ains for the life of the product. At that point the R-Value becomes stable.

What is the answer? There is one type of foam that does not temporarily capture gas in the manufacturing process. Expanded Polystyrene (EPS)

does not inject gasses into the product and therefore arrives at the job with an R-Value that will remain constant throughout its lifetime. It is manufactured with trapped atmospheric air and thus never changes its R-Value.


A drive with EPS with Leave you Surprised with Its Performance.

Take a drive with EPS Insulation and know that you will enjoy the consistent performance as your insulation of choice for below-grade, roofing, and cavity wall applications. You will feel confident that the R-Value you thought you were designing with or purchasing is exactly what was stated on the sticker.

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Insulation: Good, Better, & Best

By: Terry Meier, Sales Representative, Architectural Products

Some choices are good but others are better. Just because something is good is not necessarily reason for selecting it.

Many years ago the Sears Roebuck catalog would display some of its merchandise in 3 degrees of quality: good, better, and best.

As we consider various choices, we should remember that it is not enough that something is good. Other choices are better, and still others are best.

For over 30 years I have sold XPS foam products. I am very familiar with that product. I believe that XPS is a good product and better than many other insulation products, but is it the best choice? I don’t believe so. Even though I believe that XPS is a good product I would never have it as my first choice. Why? Because I believe that Foam-Control PLUS+® architectural EPS insulation is not only better but it is the best choice. Listed below are 6 reasons why I believe EPS is the best choice:

1. Insulation Value

  • Excavated after 15 years as side-by-side below-grade foundation insulation, the EPS had maintained 94% of its published R-value whereas XPS only retained 52% of its published R-value.
  • The R-value warranty for Foam-Control PLUS+® 250 is R-4.35 and will remain the same through its lifetime. The R-value warranty for XPS is R-value 4.35, the same as Foam-Control PLUS+® 250.

 2. Strength Characteristics

  • EPS is made in 10, 12, 15, 20, 25, 40, and 60 psi strengths.
  • XPS is made in 15, 25, 40, 60, and 100 psi strengths.
  • A wider variety of densities and strengths are available with EPS.

3. Size Availability


  • Widths 8”, 12”, 16”, 24”, 36”, 48”
  •  Lengths 2’, 4’, 6’, 8’, 9’, 10’, 12’, 16’

Thicknesses ½” up to 36” in any variation.


  • Widths 16”, 24”, 48”
  • Lengths 8’
  • Thicknesses ¾”, 1”, 1 ½”, 2”, 2 ½”, 3”

XPS is very limited in sizes and availability.

EPS is manufactured in large blocks and using hot wires are cut into desired size and shape.

4. Product Availability

  • EPS is manufactured locally with very short lead times.
  • XPS is manufactured in very few locations and has long lead times, up to 3 weeks from the time of order.

5. Water Absorption

Foam-Control PLUS+® architectural EPS insulation will absorb a maximum of 2-4% by volume when exposed to the testing specified by ASTM C578.

Recent independent testing of below-grade insulation was conducted on water absorption of expanded polystyrene (EPS) and an extruded polystyrene (XPS). Samples of EPS and XPS were excavated from the exterior foundation of a building in St. Paul, MN. The insulation was placed into service in 1993 and had 15 years of use as a vertical insulation.

Samples were tested immediately upon excavation for R-value and moisture content.

The results of the independent testing are dramatic. The EPS insulation maintained 94% of its stated R-value and had a moisture content of 4.8%. However, the XPS retained only 52% of its stated R-value and had 18.9% moisture absorption.

Short term laboratory tests of water absorption for XPS do not necessarily reflect the long term below grade performance of these materials.

6. Insect Resistant

Termites and other tunneling insects love to live, work, and eat in comfortable and protected surroundings. All untreated foam insulation products can provide this environment. Foam-Control PLUS+® can be made using a patented process using a borate mineral that is a deterrent to tunneling insects such as termites. This additive is incorporated into the foam insulation during the manufacturing process. It is safe for handling and is noncorrosive.

XPS foam is not available with this additive and is susceptible to insect intrusion.

7. Cost Per R-Value

  • At equal R-value EPS costs about 30 – 50% less than XPS.
  • When EPS is that much less expensive than XPS the choice is easy.  This choice is especially easy when there are no advantages in choosing XPS.
  •  Foam-Control PLUS+® architectural EPS is by far the best choice.

But don’t just take our word for it…

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