All About Foam Mattresses

Why Are Foam Mattresses Used And What Is Initial Force Deflection

Estimated reading time: 11 minutes

Because good foams can be extremely durable and comfortable. All foams are NOT created equal. In fact, here in St. Louis, there was a retail store called Famous Barr. A department store that was eventually bought out by Macy’s Department Store. In the 1970s through the very early 1990s, Famous Barr sold some of the finest mattresses ever built. Sealy and Stearns and Foster to name a few. They were comfortable and supportive and their comfort and support lasted for 10-15 years or more. 

In our opinion, today’s versions of most brand-name mattresses are but a fraction of the quality they once were. The mattresses of the past didn’t have problems like a premature breakdown. We call this problem a body impression, it is a permanent silhouette of your body that is indented into the many layers of cheap foam and padding used to build these new mattresses.

What Can You Do About Body Impressions In Your Mattress?

Educate Yourself: Learn how these products are built and where manufacturers cheat you so you don’t get burned.

• Buy a mattress with better quality foam.
• Buy a mattress with more total steel.
• Buy a mattress with a high-quality foundation.
• Buy a mattress with 2 sides.

Density And ILD For Foam, What They Mean

It is very important to be able to choose a quality mattress, but how do we determine what the differences are between all the components used to build that mattress. Foam is the key ingredient for comfort and durability, but do you know how to tell the difference in the layers of foam? Simply looking at a mattress will not give you any clues.  There is a running joke in the industry that mattresses are all just big white rectangles and that simply looking at them will not divulge the answers.

So, how can you distinguish the difference in ingredients between a cheap mattress that uses the poorest quality foams and a high-end mattress even though they may look identical? Price doesn’t necessarily reveal the recipe or makeup of a mattress. Doing your homework can get you what you expect for the price you pay. Remember the old adage are you getting the sizzle or are you getting the steak?

We are going to talk about mattress industry-related terms like Indentation Load Deflection (ILD) and Indentation Force Deflection (IFD). These are similar acronyms that really mean the same thing. You will also learn about foam density. Completely different than the two previous acronyms mentioned above. 

Are IFD And ILD The Same Thing?

Yes, they are in essence the same thing. ILD Indentation Load Deflection was the original name and later was substituted for the acronym IFD which is more commonly used today and stands for Indentation Force Deflection. The IFD or ILD ratings for flexible foams range from a super soft 10 to a semi-rigid 80.

Is Foam Density And IFD The Same thing?

No, Density is the measurement of weight taken on a 1 cubic foot piece of foam but is commonly confused with IFD

Technical lingo is boring, but it doesn’t make it unimportant. These fancy words and acronyms do not tell you by themselves the comfort of the foam. The fact that we add other ingredients to a mattress like base foams, springs, fiber, quilting, and fabric means the element of the foam’s feel can be changed dramatically. However, the foam’s durability and overall comfort, and level of support can give us a better understanding of IFD / ILD

IFD is one of many factors to take into consideration while shopping for a new mattress, whether it is constructed using polyurethane or memory foam.  If you are looking at these two different types of foams, they all pretty much look the same. Each is available in countless IFD variations. If you were to take a more scientific approach and measure these frequently used foam mattress paddings, you will see that there are some really major differences in foam. These measurable differences give you a way to compare 

Why Is Initial Force Deflection Or IFD important?

As you can see firmness measurement directly relates to the feel you will experience on your new mattress, sofa, or chair, etc. It gives the shopper a way to distinguish a measurable dissimilarity between two pieces of foam.

So What Is Initial Force Deflection Or IFD?

The straightforward answer is that it is the measurement of a firmness taken on a piece of foam. The foam is usually polyurethane foam or memory foam.

How Does IFD / ILD Rating Effect Mattress Feel?

 ILD / IFD is essentially an industry firmness scale of measurement. The lower number the softer the foam. The higher the number the firmer the foam.  See scale below.

• 6–12 IFD / ILD Pillows.
• 12-18 IFD / ILD Firmer pillows, soft surface padding. Envelops the body.
• 18-24 IFD / ILD Thin firm back pillows and cushioning, mattress tufting in the surface layer. Very cushy but not smothering.
• 24-30 IFD / ILD Relatively soft cradling quilt foam used in upper-middle and top layers of a mattress. Eases pressure of firmer base foams and coils without being too hard or too soft. Often described as a nice middle-ground for sleepers of average size.
• 30-36 IFD / ILD mattresses with less give. People who are looking for a gentle firm feel. Firm but with just a little give in the surface.
• 36-45 IFD / ILD Creates a very firm mattress feel. Often used for plus sizes, 250-350. Lbs. It is often as a base layer for memory foam. The bed is in boxes and on Bunkie boards as a foundation to support upper layers that are softer and cushioning. This is not used a surface layer in mattresses.
• 45+ IFD / ILD High impact shock-absorbing foam. Usually not used for mattress construction. Think carpet padding or packing foam.
• How is the Initial Force Deflection Measurement (IFD) taken?
  Using a round disc measuring fifty square inches or eight inches in diameter, the disc is placed upon a measured block of foam usually four inches in thickness. The disc is then forced down into the foam block until the foam has been compacted down to Seventy- five percent of its original thickness. The sample block of foam having an original thickness of 4 inches will now only measure 3 inches.  A measurement is then taken in pounds of force that is required to squash the piece of foam down to the standardized twenty-five percent.

Why Is High-Density Foam A Mattress Must?

Because mattresses of the past were built to last, they constructed beds only using high-density foams as mentioned above. Comfort and long-term durability were and are the result of incorporating high-density foams into mattress construction. High density is determined by the high weight of foam contained within 1 cubic foot of foam.  Fewer air cells within that 1 cubic foot of space and more foam cells give the foam a more durable structure.

Foams with less overall foam and additional air incorporated within the cubic foot are considered less dense. The high amount of air cells within that structure is therefore unable to support the applied weight from sleeping on a mattress for 6-9 hours a night. Remember, this does NOT influence how soft or firm the mattress is. Density ONLY indicates quality and durability, NOT your comfort level. Manufacturers in the past would have used a foam density of around 2.5 pounds per cubic foot. Today these same manufacturers are using .8, 1.0 1.2, 1.4 in their standard polyurethane foam for mattress production. 

There are many things that affect mattress feel; heat, humidity, density, IFD, ILD layering combinations, spring type, spring design, 1 sided, 2 sided, box spring, foundation, etc. Foam is just one ingredient in the mattress mix. Do not simply choose a mattress based on foam alone. The base is on quality ingredients that will serve up night after night of dreamy sleep.

What Are the Different Options for Memory Foam Mattresses?

Memory foam mattresses come in a variety of styles and configurations, offering options for different preferences and needs. Here are some of the most common types:

• Traditional Memory Foam
  This is the classic memory foam designed to contour to your body and relieve pressure points. It offers excellent motion isolation, making it a great choice for couples. However, traditional memory foam can retain heat, which might not be ideal for hot sleepers.
• Gel-Infused Memory Foam
  Gel-infused mattresses incorporate gel beads or layers within the foam to help regulate temperature. This option is perfect for those who enjoy the feel of memory foam but need better cooling for a more comfortable sleep.
• Open-Cell Memory Foam
  Open-cell technology improves airflow within the mattress, providing better breathability and temperature regulation. It’s a good option for sleepers who want the contouring benefits of memory foam without overheating.
• Plant-Based Memory Foam
  Plant-based memory foam uses more natural materials, such as soy, to reduce the use of synthetic chemicals. These mattresses tend to have less off-gassing and are more environmentally friendly, while still offering comfort and support.
• Hybrid Memory Foam
  Hybrid mattresses combine memory foam with other materials, like innerspring coils or latex, to balance contouring with added support and bounce. These are ideal for those who want a mix of foam comfort and traditional mattress structure.
• Firmness Levels
  Memory foam mattresses come in various firmness levels, from plush to firm, catering to different sleep styles. Side sleepers may prefer softer foam for pressure relief, while back and stomach sleepers often benefit from firmer options for spinal alignment.

Whether you’re looking for cooling, eco-friendliness, or hybrid designs, memory foam mattresses offer a wide range of choices to suit individual needs. Consider your sleep position, temperature preferences, and support requirements when deciding which type is best for you.

Frequently Asked Questions About Foam Mattresses

Q: How long does it take for a memory foam mattress to expand?

A: Memory foam mattresses usually take about 24 to 72 hours to fully expand. Right after you unpack it, you’ll see it start to puff up. But don’t worry if it doesn’t reach its full size right away. Give it some time. In a day or two, it should be ready to use.

Q: Can you use a heated mattress pad on memory foam?

A: Yes, you can use a heated mattress pad on memory foam. But keep the heat setting low. High heat can make the foam wear out faster. It can also change how the foam feels. So, use it with care to keep your mattress in good shape.

Q: How do you dispose of a foam mattress topper?

A: Disposing of a foam mattress topper is simple. You have a few options. First, you can take it to a recycling center. Some places even pick it up for you. Another option is to donate it if it’s still in good condition. Check with local charities. If those don’t work, you can put it out with your regular trash. But check local rules first.

Q: Can a foam mattress get bed bugs?

A: Yes, a foam mattress can get bed bugs. Bed bugs don’t care about the material. They hide in tiny spaces and can live in foam. Regular cleaning helps. Use a mattress cover to keep bugs out. And if you find bed bugs, treat the whole room, not just the mattress.

Q: How Long Do Memory Foam Mattresses Last?

A: Memory foam mattresses typically last 8–10 years. Higher-density foam lasts longer and resists sagging. To extend its life, use a sturdy foundation, rotate regularly, and keep it clean with a mattress cover. Replace it when support or comfort fades.

Q: Should a New Foam Mattress Have Indents?

A: A new foam mattress may show slight body impressions after use, which is normal. This happens as the foam adjusts to your body shape and weight. However, noticeable indents or sagging right away could indicate a defect.

If you’re unsure, check the warranty and guidelines from the manufacturer. Many warranties cover excessive indentations beyond a specific depth, often around 1.5 inches.

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