Everything You Wanted To Know About EPS
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Expanded Polystyrene
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We drink from it, we store food in it, we insulated our homes and offices with it, we build roads on top of it and we even transport life savings organs in it - what is it?

“EPS - The Safe Insulation”

What’s So Great About EPS

Advantages to Expanded Polystyrene

Good Insulator
EPS is a good insulator because its R-value stays consistent with no help from harmful chemical blowing agents. Depending on the density of the foam the R-value is usually around 4-R/inch. See Chart
Best Rigid Insulation Value
Expanded Polystyrene rigid insulation is the best value on the market. EPS has the Lowest Cost/Published R-Value Inch. It becomes an even better value, when compared against other insulation over time that drop in R-value, where EPS stays very consistent. Read More
Low Moisture Absorption
In field studies, EPS has been shown to absorb less moisture than previous considered. In Fact, EPS absorbed only 1/2 of a percent (.005) over 15 years in a below grade field study. Expanded Polystyrene has the great property of allowing moisture to expel out. EPS insulation exhibited drying potential under severe exposure conditions while other insulations like XPS, when exposed to the same conditions, did not. Read More
Variable Strengths
EPS has a variety of compressive strengths based on its density. This density is measured in the amount of EPS beads that are used in a cubic foot of finished product which are categorized into “Types.” . Compressive strengths can vary from 720 lbs. per sq. foot to 8,640 lbs. per sq. foot. See Chart
Fire Resistance
EPS does contain a flame retardant which help increase its resistance to fire. At 212 deg. F, EPS will begin to soften and finally melt. Although at lower temperature EPS is relatively hard to ignite. EPS does contain a fire retardant but yet is considered combustible and should not be exposed to direct flame and in certain construction applications does require a covering of a fire barrier material. Learn More
Long-Term R-Value Stability
Unlike other rigid insulations, EPS does not suffer from thermal drift. EPS’s R-value stays consistent providing a huge financial benefit for years. When one pays more for a “higher R-value” rigid insulation and it losses much of its thermal residence over time, we do not believe that offers a good insulation investment or value. See Chart
100% Recyclable
Similar to aluminum can, EPS can be recycled. In fact, in 2013 - over 34% of post consumer EPS was recycled. Learn More
Does Not Leach into Surrounding Soils
EPS is used in many application below grade or in/under soil. EPS does not leach harmful chemicals into the soil. In fact, when EPS is not recycled, many consider it to be very “Landfill Safe.” EPS actually helps the landfill by aerating the soil.
Contain No Ozone Depleting Chemicals
EPS is a closed cell foam which does not contain any ozone depleting CFCs (chlorofluorocarbons) or HCFCs (hydrochlorofluorocarbons) chemicals, asbestos or other harmful fibers.
Does Not Promote Mold or Mildew
EPS does not support a food source for molds to grow which in turn make it “mold resistant.” In fact ESP has been test to ASTM C1338 for “Fungi Resistance of Insulation Materials” and results show no mold growth over a test period time. See Report
EPS does have the advantage of being inert which means that it does undergo any biological, chemical, physical or radiological transformation. Unlike other materials that off-gas chemicals, EPS is inert.
Larger Thicker Sizes
Many insulations are limited to certain sizes like 4’ x 8’ or thickness of 4” thick. Plymouth Foam EPS can be made up to 18’ long and 48” thick. See Custom Sizes
Dynamically Manufactured EPS
Plymouth Foam EPS can manufacturing and fabrication dynamically foam to be used in many applications. EPS can be shaped to a certain size. It can be molded to exact part size. It can be glued with other EPS or materials. It can be melted to provide a void.
Sound Proofing and Sound Transmission
Sound deadening sound reduction occurs as a product of system design. EPS has effective properties when used with other products to reduce sound transmission. Three inch EPS insulation with two sided 1/4” drywall in a wall system can reduce sound transmission to approximately 36 DB. More Info STC Ratings and ASTM E-90
Our EPS is Made in USA and Made in Wisconsin
Help keep manufacturing jobs in the US and keep a better tomorrow for future generations. Learn More
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Which Insulation is better or best
Plymouth Foam Technical Information
Plymouth Foam Technical Research
Keep up to date on insulation technology
Plymouth Foam Made in USA and Made in Wisconsin
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EPS is Very Cost Effective
Compared to the other ridged insulation, EPS is by far the best value.
  • Lower Purchase PriceEPS $15.36 2” x 4’ x 8’ Board
    XPS $26.98 2” x 4’ x 8’ Board
    43% Less for EPS
  • Lower Cost/Published R-Value InchEPS $1.84/R-Value Inch
    XPS $2.70/R-Value Inch
    32% Less for EPS
  • Lower Cost/Field Study R-Value InchEPS $1.96/R-Value Inch
    XPS $5.19/R-Value Inch
    62% Less for EPS
  • Show More
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Retail Prices Arrived at by Home Depot and Gulf Eagle Supply 7/15/15
Published R-Value
EPS 4.17/inch
XPS 5.0/Inch
Fiield Study R-Value
EPS 3.92/inch
XPS 2.60/Inch
EPS has many various densities up to 8,640 PSF
EPS mechanical strength varies with its selected density or type. One way to determine the strength of EPS is by measuring its “Compressive Resistance” or capability for materials to withstand loads. EPS having resistance to compressive stress is one the most important property of a building products. In fact, Plymouth Foam’s EPS compressive resistance can vary from 1,440 - 8,640 psf at 10% strain deformation (ASTM D 1621). Design considerations should be made as to which EPS type is needed or required.
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Flexural Strength is another measurement used to determine how “durable or brittle” a product performance might be. Flexural strength is really determining its “bending strength.” EPS insulation is used in most application as a filler not a pure structural product but it is good to know the flexural strength of a product.
Note: Exposure of EPS to moisture resulting from such factors as periodic, internal condensation or moist soil conditions in foundation applications do not affect the mechanical strength characteristics of EPS thermal insulation board. 

Flame Retardant’s used in EPS insulation

YouTube Video

100% Recyclable

Post Consumer EPS Recycling Rates

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2013 - over 127 Million Pounds of EPS was recycled
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2013 - over 34% of post consumer EPS was recycled
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2013 - less than .003% of total waste in landfills is EPS and most of that could have been recycled
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98% of EPS contains regular air, which is what we breath, and 2% carbon and hydrogen

EPS Mold Report

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Custom Sizes

Need a custom size foam - no problem. We make our foam in block sizes of 4’ x 4’ x 18’ and we can cut it down to any size within.
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Custom Thickness

We offer thickness to the 1/8 of an inch up to 48 inches thick.
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