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Expanded Polystyrene Facts

Expanded Polystyrene (EPS) isn’t just foam insulation, it’s an innovative building material that lends to the design and structural integrity of many building projects. Since the 1950’s, EPS has been recognized as a mainstream insulation material, but over the past decade, new applications using EPS have expanded, and EPS now serves as a powerful design element. Today, the EPS industry uses highly sophisticated processes and technologies to manufacture cost-effective products.

EPS insulation products have been the subject of extensive research and evaluation over a 30-plus year lifespan. Encompassing a multitude of construction applications from roofing to below grade, the EPS industry stands behind its product with real-world test results. Research data from third party testing laboratories such as Oakridge National Laboratories, National Research Council of Canada, Florida Solar Energy Center, and Structural Research, Inc. lend confidence to specifiers, architects, and contractors alike.

Long-term Insulation Value

The thermal resistance, or R-value, of EPS may be used without any adjustment for aging.

Temperature Cycling

EPS is able to withstand the abuse of temperature cycling, assuring long-term performance.

Energy Savings and the Environment

EPS insulation systems reduce energy consumption. With energy savings comes environmental benefits. Specifically, the reduction of fossil fuels burned to create energy. By reducing our energy consumption, we reduce combustion by-products that lead to smog and contribute to global warming.

EPS is Recyclable

After its original life as insulation, EPS is 100 percent recyclable, and can be recycled into a variety of consumer and industrial products. Recycled EPS is ground and reincorporated into new EPS products or thermally processed to make a resin that can be used to remanufacture new polystyrene products. Northwest Foam Products, Inc. has been reprocessing in-plant scrap for many years. 

Landfill Safe

EPS is inert and stable. EPS does not produce methane gas or contaminating leachates.

Strength Characteristics

The resilience of EPS insulation board provides reasonable absorption of building movement without transferring stress to the outer skins at the joints.


EPS is combustible. It should not be left exposed to flame or other ignition sources. EPS insulation should be covered with a thermal barrier or otherwise installed in accordance with applicable building code requirements.

Moisture Resistance

A study by the Energy Materials Testing Lab (EMTL) has shown that EPS insulation installed in well-constructed roofing does not absorb appreciable moisture, even under conditions characteristic of prolonged, cold, and damp winters.

Environmental Impact

EPS insulation is an inert, organic material produced from petroleum and natural gas by-products. EPS insulation does not contain chlorofluorocarbons (CFCs) or hydrochlorofluorocarbons (HCFCs).

Resource Efficient

EPS manufacturing uses little energy and creates little pollution. EPS products save resources by reducing energy consumption through insulation systems.

Waste to Energy Safe

EPS provides a clean source for WTE incineration systems. The chemical makeup of EPS is carbon and hydrogen, elements found in wood and other organic materials.

Cost Efficiency

EPS insulation typically costs less than other rigid board insulations when compared on the basis of R-value.

Solvent Attack

EPS is subject to attack by petroleum based solvents.

Vapor Barriers

Although EPS provides a high level of moisture resistance and breath ability, recommended design practices for walls and foundations should be followed in the selection of vapor and moisture barriers for severe exposure.

Ultraviolet Degradation

Prolonged exposure to sunlight will cause slight discoloration and surface dusting of EPS insulation. The insulating properties will not be significantly affected under normal usage.

If you have any questions about the above facts, be sure to contact us at Northwest Foam Products, Inc. today!