What Is Styrofoam?


There’s Only One Styrofoam™ (and it’s not a cup)

When people hear the word “Styrofoam,” they often think of foam cups, fast food containers or packaging. But construction professionals know better. Unlike the expanded polystyrene (EPS) foam that’s used to make disposable containers, DuPont™ Styrofoam™ Brand Extruded Polystyrene (XPS) Insulation is a high-performance, closed cell foam used to insulate homes and buildings. That closed cell structure is what gives Styrofoam™ Brand the thermal protection and moisture resistance that help buildings stay warm in the winter, cool in the summer and dry year-round.

What is ‘closed cell’ foam? If you look under a microscope at the white EPS foam you know as disposable cups, coolers and packaging, you’ll see gaps between the foam cells. Over time, those gaps let in air and moisture. Those gaps also reduce the material’s compression strength. Ever crushed a foam cup in your hand? That’s low compression strength! However, if you look at Styrofoam™ Brand XPS Insulation under a microscope, you won’t see those gaps. It’s a closed cell foam that provides exceptional thermal, moisture and air protection for homes and buildings. It also has great compression strength, so it can withstand the demands of a tough jobsite, last for decades and even be reused when buildings are remodeled!

Now that you know there’s only one Styrofoam™ Brand  and it’s not a cup – what should you call those white foam cups, containers, coolers and packages? EPS, polystyrene or foam are all accurate terms to describe EPS material. Styrofoam™ is an entirely different material – a rigid board insulation invented in 1941, trademarked and, until a major reformulation in late 2023, known for its distinctive blue color. The newest generation of Styrofoam™ Brand XPS is now produced in grey, signifying its low global warming potential formulation.



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Frequently Asked Questions

  • A: Styrofoam™ Brand XPS is an extruded polystyrene (XPS) produced as a rigid board insulation used to provide thermal, moisture and air protection in homes, buildings, insulated trucks, roofs, highways, tunnels, insulated pipes and other places of shelter and infrastructure that are designed to last decades.

  • A: They don’t exist. In fact, there isn’t a cup, food container, cooler or packaging material in the world made from Styrofoam™ Brand material. Those items are made from a type of expanded polystyrene (EPS) that doesn’t have the insulation value, moisture resistance or compression strength of Styrofoam™ Brand.

  • A: We can think of two good reasons it matters that there’s no such thing as a Styrofoam™ cup, food container, cooler or packaging material. Number one in our book is protecting the reputation of a product that we think is pretty great – Styrofoam™ Brand XPS Insulation. It’s trademarked and an entirely different material than the expanded polystyrene (EPS) foam used to make one-time use containers. Secondly, it’s a way to place an easy bet at parties. Bet your friends they can’t find a Styrofoam™ cup. They won’t, because it doesn’t exist!

  • A: Simply look for the genuine Styrofoam™ Brand trademark! DuPont holds more than 150 trademark registrations worldwide for the Styrofoam™ Brand.