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What is the difference between a sofa cushion's foam density and firmness?

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Although most people think that a cushion's foam density and firmness are synonymous, they are actually very different.

The density of foam is found by weighing a 12″ x 12″ x 12″ block of the material. If a product has a 2 lb. density, that means a 12″ x 12″ x 12″ foam block weighed 2 lbs.

Cushion pile

Although density does not pertain to the firmness of a foam cushion, it does correlate to the quality and longevity of that cushion.

Each foam density is available in a wide variety of different firmnesses.

Most foam suppliers typically stock four or five commonly used densities for residential furniture seat cushions ranging from 1.5 to 2.5. The number designates the weight (in pounds) of 1 cubic ft. of foam.

Each of these different densities may be available in 10 or more different firmnesses ranging from very soft to very firm.

Cushion construction is the single most important factor in determining the lifespan (and comfort) of your sofa, couch or chair.

The expected lifespan of a foam cushion is primarily dependent on the density and thickness of the foam.

Another important factor is whether the foam is HR (High Resiliency) which recovers its shape better after use.

A foam cushion's "firmness" has very little effect on the expected lifespan.

Since most consumers equate “firmness” with durability, cheap foams are often made “extra firm.” With a low density foam, however, that “extra firm” feeling will not last long.

Foams used in seat cushions for moderately priced residential furniture generally range from 1.5 through 2.0.

The most common foam density by far for residential seating is 1.8. Depending on the thickness of the foam, whether or not it is HR (High Resilience) and how much use the couch gets, a 1.8 density cushion will typically begin to lose its shape and resilience in 1–3 years.

After 3–5 years a 1.8 density cushion will normally need to be replaced. Few retailers or manufacturers offer replacement cushion inserts.

Since replacing cushions is not simple or cheap many people choose to purchase another sofa when their cushions wear out.

Replacing worn out cushion insides requires going to a professional upholsterer (or re-upholster.) The cost for purchasing a new set of custom cushions can get very expensive.

The result is that many consumers choose to purchase a new sofa when their cushions wear out, even though the frame, foundation and even the fabric may still be in excellent condition.

Lower density foams are typically used for back cushions or padding that goes over the arms or other parts of the frame.

Higher densities (2.0 - 2.5) can be found on more expensive residential furniture.

Furniture designed for heavy commercial or institutional use may use foam with densities of 3.0 or higher.

The higher the foam density the more the cushion will cost. Variations in firmness usually do not affect cost. HR (High Resiliency) foam is more expensive (and more durable) than non-HR foams.

The most commonly used foam density for residential furniture sold in the U.S. is 1.8.

The term "High Density Foam" is almost meaningless. It is used in marketing materials to describe virtually any foam from 1.8 density and up.

The foam core is usually anywhere from 4″ - 6″ thick and is typically wrapped in a dacron polyester fiber. The wrapping may consist of a layer of memory foam in place of the dacron polyester.

The fiber (or memory foam) wrapping is generally 0.5 - 1.5" thick on the top and bottom of the cushion. It softens the feel of the cushion but has no effect on lifespan.

A 4" thick foam core made with 1.8 density HR (High Resiliency) foam can be expected to last about 2 years with average use before the foam begins to lose its ability to bounce back and keep its shape .

A 5" thick foam core made with 1.8 density HR (High Resiliency) foam can be expected to last about 3 years with average use before the foam begins to lose its ability to bounce back and keep its shape.

Foam cushions will typically still be usable for another couple of years after the deterioration process begins. Foams that are not High Resiliency will deteriorate more rapidly.

Actual foam densities will vary during the manufacturing process. A variation of 0.1 is considered normal. A 1.8 density foam may actually be 1.7 or 1.9. Larger variations are not unusual.

There are many couches sold with cheaper (and lighter weight) 1.5 density foam that will deteriorate even more rapidly, sometimes within one year of purchase.

The overall thickness of the cushion may or may not be an indication of a cushion’s durability.

sofa with collapsed cushions

“Value priced” couches will sometimes have cushions that are bulked up with several inches of polyester fiber around the foam core.

The excess polyester fiber will rapidly compress causing the cushion to lose its shape.

If you want to get more than 5 years of use from your couch you will need to find a couch with a better quality cushion.

Higher priced couches generally use thick higher density foams with at least a 2.0 density. but preferably higher.

More expensive cushions may also include coil spring construction, sometimes with a layer of down and feathers to give a long lasting cushion with a softer feel.

Plush cushions made exclusively with down and feathers used to be very popular in high end furniture long ago, but are rare now. Aside from the very high cost, down and feathers have very little resiliency and need to be "fluffed up" after each use.

When shopping for a couch always test the cushions by picking them up. As a general rule if the seat cushions feel “light” you are looking at a couch with a very short expected lifespan.

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  1. Anita Cannon Anita Cannon Want to replace foam in sofa cushions. What kind of grade/type foam should I ask for best comfort and durability? Not getting much help from local upholstery shops. Thank you.
    Wednesday, October 17, 2018
  2. Jeff Frank Jeff Frank Thank you for your question.
    Local upholsterers typically deal with small suppliers that offer a limited number of generic foams.

    An experience upholsterer knows that comfort is very subjective. He doesn't want to be in the position of having recommended something that you may not like (either immediately or one year later.)

    There are many variables, including the thickness of the cushions. For example my company uses 2.5 density foam in an 8.5 inch thick cushion. If we were using 6 inch cushions it might be better to go to 2.8 density foam.

    Your upholsterer also wants to make something simple. If you ask for a foam cushion he will want to use a single type of foam. He does not want to spend time gluing multiple layers of different types of foam, which is often done in commercial upholstery.

    The safest thing for you to do is to ask for spring down cushions. Any good upholsterer has worked with those and can get the materials from a local supplier.

    Spring down cushions are constructed with a foam border surrounding the coil springs. This foam border is typically standard generic 1.8 density foam, even in high end spring down cushions. You don't really need a higher density because the primary weight is going to be on the springs and not the foam.

    Above and below the foam border and coil springs is a down-proof fabric jacket filled with down and feathers (or polyester fiber) which softens the feel between your bottom and the springs.

    There are many different combinations of this. Polyester fiber is much cheaper than feathers which are much cheaper than down.

    Most mass produced spring down cushions are currently using a combination of 50% polyester fiber/5% down/45% feathers. Top quality cushions may use 50% down/50% feathers.

    There can be a substantial difference in price between these extremes and many people can't tell the difference when they sit in the new cushions, although polyester will compress more over time. Down has the best long-term loft and softness but is very expensive.

    For the best compromise between cost, durability and long term comfort you may want to go with 10% down/90% feathers. Most upholsterers should be able to do this. Wednesday, October 17, 2018
  3. Mark Mark Is a manufacturer required to give out the density of their foam for their cushions? When I unzip the cushion are the markings on the cushion revealing the density? Is it on the sofa tag at all?

    I'm guessing the answer is "no" to all of this, and I can only assume these 00 - Core: Blog,500 sectionals we are looking at are all pretty bad stuff...

    Appears the highest-end players have survived due to margin, thus still in the game, but the middle-makers have been pretty much squeezed out of the industry due to off-shore and "US manufactured" garbage-is product...

    At least, with all the research we've (the Mrs. and me) have done this appears to be the case. If I'm right, it is sad that more people don't do their homework instead of buying cheap, thinking they are getting something great, only to be upset just months down the road.

    Simplicitysofas look fantastic, but wow, way on the high-end of things. Thanks for the all information however, I won't recommend what I think we are going with, but it's as close to a "middle" range as I think we can find. Sunday, January 13, 2019
  4. Glenda Cuddy Glenda Cuddy I'm a very heavy woman so keep that in mind when recommending my cushion. I'm looking to get a cushion that I can set on top of my lift chair for added comfort and support. It can't be more then 3" high because it's going on top of the existing cushion. What would you recommend? Monday, April 15, 2019
  5. The author It is my experience that trying to put a second cushion on top of an existing cushion never results in a comfortable long-term solution.

    If your lift chair has a removable seat cushion it may be possible to have a new (higher) cushion made, but the vast majority of lift chairs have built-in attached seat cushions which cannot be modified. Monday, April 15, 2019