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What are Polystyrene Sheets?

Polystyrene sheets are versatile, lightweight plastic panels used in various applications, from insulation to crafting. They're known for their excellent thermal resistance and shock-absorbing properties, making them a popular choice in construction and packaging. With a myriad of uses, these sheets can be a game-changer in your next project. How might polystyrene sheets enhance your creative or commercial endeavors?
B. Turner
B. Turner

Polystyrene sheets are thin layers of material made from polystyrene foam. These sheets are often referred to as Styrofoam® sheets after a popular brand name product made from this material. This foam consists of hydrocarbon molecules derived from petroleum, which are infused with air and molded into sheets roughly the size and shape of plywood or drywall. In addition to providing excellent insulating properties, these sheets also offer a degree of structural strength, making them an effective option for a wide range of applications.

Buyers can choose from two basic varieties of polystyrene sheets, which differ in how they are manufactured. Extruded polystyrene sheets (XPS) are made of polystyrene beads that are melted and forced through a metal die or mold. These sheets feature a dense, closed-cell construction, and are stiffer and stronger than other polystyrene sheets. Expanded polystyrene sheets (EPS) are made from polystyrene beads that are infused with air and pressed together in molds or forms. EPS features a slightly less dense construction than XPS, making it less effective for structural applications.

Polystyrene foam -- often associated with insulation -- can be used to make sheets of Styrofoam.
Polystyrene foam -- often associated with insulation -- can be used to make sheets of Styrofoam.

One of the most common uses for polystyrene sheets is as a form of building insulation. These panels can be installed in wall cavities or under roofing or siding to help improve thermal resistance between exterior and interior surfaces. They are also used in specialized building materials, including structurally insulated panels (SIPs), and insulated concrete forms (ICFs). Polystyrene sheets are also used to protect goods and packages during shipping, and to line coolers or freezers. These sheets can also be used to make signs, or in arts and crafts projects.

Polystyrene sheets provide excellent insulation properties.
Polystyrene sheets provide excellent insulation properties.

While polystyrene sheets provide many advantages to users, one of the major benefits associated with this material is its excellent insulating properties. These sheets offer a much higher level of thermal resistance than traditional fiberglass or cellulose insulation products, which helps to improve energy efficiency and keep heating and cooling costs in check. Despite their structural strength and durability, these panels are also easy to cut, shape, or form using only basic tools and equipment.

Polystyrene sheets are also associated with a number of potential limitations or drawbacks. These sheets cost more than alternate insulation materials, which could impact construction budgets for homes and commercial buildings. Foam insulation sheets must also be covered by drywall or some other fire-resistant medium when they are used in a residential setting. This is due to the relatively high flammability of these petroleum-based sheets.

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Discussion Comments


I save and use the stuff from packing. Stuff them

into gaps in unfinished attic for insulation. Use

little blocks to cover exposed nails in attic, looks funny but better than ramming a nail into my head! Put it under legs of furniture stored in garage, on an on!


I draw pet portraits with charcoal, and I often have to ship them to the buyers in other states. Polystyrene sheets help these drawings stay flat, and they arrive in pristine condition.

First, I make sure to spray a fixative over the drawing. This will keep it from smudging as easily. Then, I lay a sheet of wax paper over the surface of it.

Next, I place the drawing in between two flat sheets of polystyrene. I have a supply of cardboard boxes that these sheets fit into snugly, so stuff doesn't shift around in transit.

I have never had a complaint about a wrinkled or smudged drawing, so the polystyrene is doing an excellent job. I can't think of a better way to ship something that needs to stay flat.


@wavy58 – That is a good idea! I will have to remember that next time I make candy to take to a party, because I have a ton of old polystyrene sheets in my closet.

I never throw away packing materials, because I want to be prepared in case I ever have to move. I have found another use for the polystyrene in the meantime, though.

I encourage my daughter to develop her creativity, and since she loves to paint and draw, I frequently hang her artwork around the house. I have been using the polystyrene sheets as backboards for it, since they are thick enough to carve a notch into and mount over a nail in the wall.


I order a lot of products online, and they are almost always shipped inside a box lined with polystyrene sheets. The sheets are usually molded to fit the curves of the item, so they can hold it snugly in place and act as a good cushion.

Rather than throw these away, I like to save them and cut them up in chunks for different purposes. I used them as a base for my toothpick and paper signs last year, and being able to cut them to the right size helped a lot.

I was making lemon and orange truffles for a party, and I needed a way for people to distinguish between the two. I cut out little squares of polystyrene and stuck a toothpick into each one. To the top of the toothpick, I taped some paper with the words “lemon” and “orange” on it.

The polystyrene was thick enough to serve as a sturdy base to the lightweight sign. I was able to stick them in between the truffles on a plate, since they were so small.


I use a few polystyrene sheets in my cooler to pack things in place. If I'm only taking a couple of bottles of water, along with a frozen gel pack, then I use the sheets to hold the ice up against the bottles and to keep them from rolling around.

I use some small sheets of polystyrene in between certain things in my cooler. If I'm taking a sandwich and something heavy, like a bowl of soup with a lid on it, I will place the sheet between the two so that the sandwich doesn't get smashed.

Some of my friends think I'm strange for using insulation inside an already insulated cooler, but I think it keeps things even colder. The fact that it doubles as a divider makes it the ideal tool.

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    • Polystyrene foam -- often associated with insulation -- can be used to make sheets of Styrofoam.
      By: brozova
      Polystyrene foam -- often associated with insulation -- can be used to make sheets of Styrofoam.
    • Polystyrene sheets provide excellent insulation properties.
      By: peuceta
      Polystyrene sheets provide excellent insulation properties.