Expanded polystyrene is a type of foam made from polystyrene. It is a lightweight, rigid and closed cell insulation. Extruded polystyrene is another form of foam made from polystyrene. The trademark name for this product is Styrofoam (by The Dow Chemical Company).

What is extruded polystyrene used for?

Polystyrene is a synthetic, hydrocarbon polymer derived from benzene and ethylene, two petroleum products. XPS foam board is often used for above-grade insulation applications such as walls, ceilings, attics and roofs as well as for below-grade applications such as foundations and basements.

What is extruded polystyrene made of?

What is Extruded Polystyrene or XPS Polystyrene Foam? Extruded Polystyrene (XPS), is manufactured via an extrusion process where plastic resin and other additives are combined and extruded through a die. The extruded foam then cools and expands into it’s final shape.

What are the different types of Styrofoam?

Three major types of polystyrene include polystyrene foam, regular polystyrene plastic, and polystyrene film. Amongst the different types of foam are expanded polystyrene (EPS) and extruded polystyrene (XPS). EPS includes the most well-known and common types of polystyrene to include styrofoam and packing peanuts.

What is difference between XPS and EPS?

XPS is manufactured in a continuous extrusion process that produces a closed cell form of foam insulation. EPS, on the other hand, is manufactured by expanding spherical beads in a mold and then using heat and pressure to fuse the beads together.

Is extruded polystyrene foam waterproof?

Foam board insulation doesn’t absorb water, which essentially limits the amount of moisture build-up in your insulation. Polyiso and extruded polystyrene foam boards have the strongest waterproof properties.

Is extruded polystyrene foam toxic?

Expanded Polystyrene (EPS) or Styrofoam, is a petroleum-based non-biodegradable foam, which the EPA and International Agency for Research on Cancer consider styrene a “possible human carcinogen” and “that such materials can have serious impacts upon human health, wildlife, and aquatic environment, and the economy.”

What does extruded polystyrene look like?

This continuous process produces a closed-cell structure that looks like a mass of uniform bubbles with common walls between them. A continuous smooth skin on the top and bottom also forms. The closed-cell structure of extruded polystyrene (XPS) foam imparts excellent long-term strength and durability.

What is the difference between EPS and styrofoam?

As we said, Styrofoam™ is a Dow trade, blue in color, and is an extruded polystyrene (XPS) foam made for thermal insulation, construction and craft applications. EPS is an expanded polystyrene available in various densities for insulation, construction and craft applications and so much more.

What is the R value of 2 inch thick extruded polystyrene foam?

Extruded Polystyrene Foam XPS has an R value of 4.5 to 5.0 per inch of thickness. This is the product that I typically use to insulate basement walls.

Article first time published on

What is Dow Styrofoam?

Styrofoam Brand Foam by Dupont (formerly Dow Chemical), typically referred to as “blue board” is the best known extruded polystyrene insulation on the market today. Manufactured by Dupont, Styrofoam Brand Foam is available in a variety of thicknesses in both 24″ x 96″ and 48″ x 96″ dimensions.

What is the difference between Type 1 and Type 2 insulation?

Type 1 polystyrene insulation has a typical thermal resistance value or R3. 7/in., while Type 2 polystyrene insulation has a minimum thermal resistance value of R4. 0/in. Type 1 is moulded bead polystyrene.

How long does extruded polystyrene insulation last?

Expanded Polystyrene (EPS) is essentially inert. There have been multiple studies of EPS in the soil for 15 to 30 years demonstrating only minor degradation of the EPS foam. EPS foam is expanded using steam. It is the entrained air that provide the insulation value in the material.

Is EPS foam closed cell?

Expanded Polystyrene Insulation, more commonly referred to as EPS, is a closed cell insulation that has been around since the 1950’s. EPS is made of 98% trapped air and only 2% plastic, making it an efficient insulator with a small amount of raw material.

How good is EPS insulation?

EPS is an extremely durable material Expanded polystyrene will last the lifetime of any building where it’s installed. The thermal performance of EPS does not degrade over time, meaning the U-value you first achieve with EPS will not change.

Which is best EPS or XPS?

In general, when comparing EPS and XPS board densities, the compressive strength of XPS is greater than that of EPS. For EPS to achieve the same compressive strength as XPS, the density of the foam would need to be increased, often resulting in a greater thickness of board being required.

What is the healthiest type of insulation?

• Cork. When it comes to healthy insulation, cork tops the list, at least according to a report done by Energy Efficiency For All. …
• FIberglass. …
• Cellulose. …
• Recycled Cotton. …
• Sheep’s Wool.

Is EPS safe?

EPS is non-toxic, chemically inert, non-irritant and odourless making it entirely safe to use across all construction applications.

Is EPS insulation safe?

Polystyrene insulation (EPS) has very poor fire resistance but is better if, like most modern insulation, it has a fire retardant added to it. … It would probably contain a fire retardant. PIR and PUR (polyurethane foam) have reasonable fire resistance and phenolic foam has a high fire resistance.

How can you tell if foam is EPS?

You will often see original Styrofoam sheets in a blue color while EPS foam blocks start out as white, unless custom dyed. EPS foam is lightweight but has a high-density which makes it stronger and more durable than Styrofoam.

What is the difference between pink and blue foam board?

Main Difference Between Pink And Blue Foam Boards Both are manufactured using the same process and contain similar chemical components. … However, blue foam boards are manufactured by Dow Chemical Co. whereas the pink foam boards are manufactured by Owens Corning company.

What happens to styrofoam when wet?

The reliability of styrofoam as a waterproof material also decreases when used in winter conditions. As polystyrene sheets absorb and store water, the expansion and contraction of water molecules as it turns to ice can compromise the pellets’ integrity and make the styrofoam piece break off with time.

Is EVA foam the same as Styrofoam?

EVA foam is a new type of environmentally friendly plastic packaging material. EVA rubber and plastic products have been designed and formed, and its shockproof performance is better than traditional packaging materials such as polystyrene (foam).

Is EPS foam fire resistant?

It is both the fire retardant and the insulation value of the foam that makes it perfectly suited to help protect structures during a wildfire. … Untreated EPS foam burns at 650° to 700°F with a flame source. It won’t continue burning on its own until 840° to 930°F is reached. Wood burns at 480° to 660°F.

Is EPS foam flammable?

Like practically all organic building materials polystyrene foam is combustible. … Although foam insulation is relatively difficult to ignite, in the case of ignition, burning will readily spread over the exposed surface of the EPS and it will continue to burn until all EPS is consumed.

How do you cut extruded polystyrene?

Extruded polystyrene can also be cut while standing upright. After cutting 1/4 inch into the front, push a knee into the backside of the sheet where the cut is, then pull the two sections back until they snap. You may need to use a utility knife to cut through the last remaining bit of plastic covering.

What is extruded foam insulation?

Extruded polystyrene insulation or XPS Insulation is manufactured through an extrusion process. This manufacturing process involves melting together the plastic resin and other ingredients. The liquid formed is then continuously extruded through a die and expands during the cooling process.

How do you glue extruded polystyrene?

1. Cyanoacrylates – All Permabond cyanoacrylates bond well to polystyrene. …
2. Two component epoxies bond well to polystyrene. …
3. UV Curable – UV Curable adhesives are an excellent choice for bonding polystyrene.

What insulation has the highest R-value?

Vacuum insulated panels have the highest R-value, approximately R-45 (in U.S. units) per inch; aerogel has the next highest R-value (about R-10 to R-30 per inch), followed by polyurethane (PUR) and phenolic foam insulations with R-7 per inch.

What rigid foam insulation is best?

Expanded polystyrene (EPS), or beadboard, serves as the best insulating rigid foam for homeowners on a budget. This material costs less than other rigid foam boards, but still offers an R–value of 3.6 to 4.2 per inch, according to Fine Homebuilding.

Can I use styrofoam for insulation?

Styrofoam is also a material that has great insulating properties. … I could make a wooden form, then create blocks of insulation that would fit between the 2 x 4 stud walls.