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What is Urethane Foam?

John Lister
John Lister

Urethane foam is an artificial material with several different uses. The manufacturing process can produce foams of varying densities and flexibilities, which means that it can serve functions as diverse as bedding, packaging and footwear. It is important to note that urethane foam is most commonly used to refer to a material made from polyurethane. The urethane reference in this name is to the type of links, also known as carbamates, that join the units in polyurethane. There is some potential for confusion as the word urethane on its own is often used for a specific carbamate also called ethyl carbamate, but despite the name, this substance does not appear in the foam.

Perhaps the best known use of urethane foam is in bedding, such as mattresses. Because it is artificial, the foam can be made to a particular density, meaning manufacturers can offer a range of mattresses with different degrees of softness or firmness and even produce a mattress to order. The foam itself does not have the heat sensitivity used in memory foam mattresses that adjust to fit the user's sleeping position, but many such mattresses will use it for the base, with the visco-elastic "memory foam" acting as a topping. This is an effective way to get some of the benefits of the memory foam, while keeping overall costs down

Urethane foam is an effective insulator than can be applied as a spray.
Urethane foam is an effective insulator than can be applied as a spray.

Urethane foam can also be used for insulation, such as in attic roofs. The biggest advantage of the substance for this use is that it has a very low lambda value, which is the measure of how much heat it transfers, meaning it is a very effective thermal insulator. It is also particularly useful for insulation as it can be delivered in the form of a spray, which then hardens. This means the foam can be applied to any area and will fit the space perfectly. This removes the problems that come from applying insulation boards that have to be resized and may still leave gaps through which heat can escape.

Footwear sometimes contains urethane foam.
Footwear sometimes contains urethane foam.

There have been some medical questions raised about polyurethane foam. These include the respiratory health risks involved in applying the foam in uses such as insulation, and the dangers associated with the flame retardant treatment that must be applied to furniture made with it. Companies using the materials should follow established industry guidelines to ensure worker safety. While there are some claims that this foam can cause health risks for consumers, the evidence to back these claims is disputed and is not widely accepted.

Discussion Comments


Please tell me about non yellowing foam. How is it made?


Can I get some info for the HS Code for urethane foam?


@shell4life - I used to sit on an old piece of urethane foam from a cushion when I was a kid, and it served as the official sofa of my imaginary playhouse. That stuff was nice and soft, but man, would it retain water for a long time!

For days after a rain, I couldn’t sit on my foam sofa without getting my pants soaked. You couldn’t always see the water, either. It hid out inside the foam somewhere, just waiting to play a prank on me.

I used that foam for years, until I got a puppy and he tore it to shreds. Now, I have a real sofa with the urethane foam tucked safely away inside, safe from moisture.


I’ve noticed urethane foam inside of seat cushions on everything from bicycles to sofas. You generally don’t become aware of it until your seat becomes damage to reveal the yellow foam beneath, though.

When I moved into the house I currently rent, there was an old car seat in the shed out back that had been torn apart by animals. Something had ripped out the urethane foam, and it lay inside the shed, totally exposed.

My dog started sleeping on it at night. He’s pretty smart, because he picked up on the fact that it would make a great bed. I think it’s funny that my dog is sleeping on a scrap piece of what we humans actually use for bedding.


I have seen that urethane spray foam, and it is weird looking once it is applied. The white kind looks like a melted bunch of marshmallows, and the yellow kind looks like some sort of mushroom.

I didn’t know what it was when I saw a glob of it in my yard. My dad had been spraying it into some gaps where the sides of his workshop met the walls to keep the wasps from building nests in there, and some of it had fallen to the ground.

I thought it was some sort of weird fungal growth! I asked him about it, and he told me that it was a type of insulation that could be sprayed into cracks.


I suspect that there is urethane foam in my mattress. It was really cheap for a memory foam mattress, and even though I got it at a discount warehouse, I believe that it must not be 100% memory foam.

This doesn’t bother me one bit, though. What would I do with that much memory foam, anyway? It’s only the top few inches that make a difference in comfort and temperature. Having more than that would be a waste.

As far as health concerns, I don’t put much stock in what is said about urethane foam. If you listen to every warning you hear, then you will find yourself unable to use anything in this world out of fear for your health.


Is Polyurethane foam in pillows harmful to your health?


What kind of Polyurethane foam is needed for noise absorption?

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    • Urethane foam is an effective insulator than can be applied as a spray.
      By: auremar
      Urethane foam is an effective insulator than can be applied as a spray.
    • Footwear sometimes contains urethane foam.
      By: Mikael Damkier
      Footwear sometimes contains urethane foam.
    • Urethane foam is typically used to make memory foam mattresses.
      By: WavebreakMediaMicro
      Urethane foam is typically used to make memory foam mattresses.