How Mattresses Are Made
This content was created by the National Sleep Foundation
Mattress construction from the inside-out
If reading about mattress construction sounds like a real, ahem, snooze, know this: The way a mattress is made determines how it feels. And how a mattress feels may be the difference between a fitful night and peaceful slumber!
The Big Picture
Two basic types of mattress make up the vast majority of the market: They’re called innerspring and memory foam. Made of steel coils, innerspring is, by far, the most common type. Memory foam, on the other hand, is made from polyurethane or latex foam, and is very dense foam. Memory foam is usually more expensive than innerspring.
Inside an Innerspring Mattress
Coils determine how much support (suspension versus springiness) the mattress will give. Manufacturers may use different types of coil shapes and structures, as well as different amounts of spacing and patterns to affect comfort. The next layer, top padding, isusually made from polyurethane foam. The outer layer (or ticking) is the material bound to the top padding with stitching. The way that ticking and top padding are attached influences the mattress’s overall feel. Large, wide patterns will create a cushioned feel, which smaller patterns feel tighter and firmer. Generally, the more coils an innerspring mattress contains, the more comfortable it’s bound to be—but if the number of coils is over 390, then you’re not likely to notice the difference, so don’t bother paying extra.
Inside a Memory Foam Mattress
Especially attractive to people with chronic pain conditions, memory foam mattresses consist of, essentially, very dense foam. When you lie on a foam mattress, your body heat softens the material, allowing it to “mold” to your body. One big advantage: In bigger beds, a memory foam mattress won’t shift as much as an innerspring when one partner turns or moves. So if you’re often disturbed by your partner’s tossing and turning in the middle of the night, it might be time to invest in a memory foam mattress. But one con: Because these mattresses mold to your body, they can absorb a lot of heat and make you feel hotter while you sleep. Some people also complain that they have a chemical smell.
How Latex and Memory Foam Mattresses Are Made
There are a couple of reasons why you might be interested to read what I have on this section of my website. The first is that you have a natural curiosity about how the products you buy are made, and considering you’ll be spending up to one third of your life on a mattress, I can’t blame you for wanting to know.
The second reason might be because you’re concerned over how eco-friendly a mattress is, and again, I can’t blame you. After all, we’re constantly told how we should treat our planet better and the dangers that certain materials can pose to our health.
So, no matter what the reason I thought it would be a good idea to let you know how latex and foam mattresses are made. Of course, if you’re familiar with latex you may think this is the most natural substance a mattress can be made from, and you would be right since the raw material is drawn directly from the rubber tree.
However, if you are erring on the side of a latex mattress do be careful of the actual amount it contains because manufacturers use three different forms: 100% natural, 85% natural and 15% synthetic and finally 20% natural and 80% synthetic. Of course, the more natural a latex mattress is the more expensive it will be.
In respect of memory foam mattresses, the materials used are synthetic and this is one of the reasons why I come across so many complaints about the “outgas” odor many of them give off when they’re brand new. Whilst this can be a little worrying, if you’re careful to look for the CertiPUR-US certificate this will guarantee that your mattress is gentle on the environment and isn’t bad for your health.
If you’re interested in finding out about the whole process, why not have a little peek at the short video I have included below?
The Definitive Guide to Memory Foam Mattresses
Astronauts not only landed on the moon—they’re also (indirectly) responsible for changing the way Americans sleep. In the 1960s, NASA commissioned researchers to develop seating foam that would keep test pilots better cushioned during flights. They came up with memory foam (originally called “slow springback foam”), and the rest is history. The material is now used in everything from mattresses to movie theater seats to football helmets.
The innerspring mattress might still be the most popular sleep surface (it, too, was inspired by transportation—in this case, buggy seats of the 1800s), but memory foam is the fastest growing category of bedding. In fact, Research and Markets projects that the memory foam mattress and pillow market in the United States will reach more than $8 billion by 2023.
If you’re considering a new memory foam mattress, here’s everything you need to know, from what’s between the covers to how to assess quality to which type of sleepers memory foam suits best.
What is a memory foam mattress?
A memory foam mattress is one made from viscoelastic foam, a type of high-density polyurethane foam. (Greener versions of memory foam use plant-based ingredients like soybean oil in place of some of the petroleum derivatives.) Memory foam’s distinguishing feature is that it softens in response to heat and pressure. That’s what gives it the body-hugging feel many sleepers love.
Most memory foam mattresses aren’t made solely from memory foam, though. If they were, they’d be so soft that you’d sink too deeply into the bed. Instead, premium memory foam mattresses feature layers of foams in varying thicknesses and densities for the optimal balance of comfort and support.
What’s inside a memory foam mattress?
There are a handful of components common to most memory foam mattresses. The bottom layer is thesupport core, which is often made from polyurethane foam and is strong enough to support the body’s weight, says Bill Fish, a certified sleep science coach and founder of the sleep website tuck.com. From there, you’ll likely find a layer oftransition foam, followed by a top comfort layer (or multiple layers) ofmemory foam.
When comparing memory foam mattresses, these are the key things to look for:
“While it isn’t an exact science, the rule of thumb is that the higher the foam density the higher the quality and the heavier the mattress,” says Fish. (Memory foam mattresses often weigh upwards of 100 pounds.) Higher density foam translates into a more durable mattress that should last you anywhere from 10 to 15 years. Fish suggests looking for foam density of at least 3 pounds per cubic foot. Premium memory foam has a density of 4 to 5 pounds per cubic foot.
Keep in mind that you may have to go digging for this info, though, notes Fish, as it’s often not front and center. “By looking through the brand’s website or speaking to their customer service team, you should be able to find this information the vast majority of the time,” he says.
If you’re shopping for a memory foam mattress, no doubt you’ve come across the trend of “beds in a box.” “Many of today’s popular memory foam mattresses are first compressed down to one inch, vacuum sealed, rolled, and placed into box prior to shipping,” Fish says. They’re then sent via UPS or FedEx to the customer’s doorstep. While beds in a box are cost-effective and convenient, they are made with lower-density foam so that they can be squeezed into a box.
Learn More About Saatva’s Memory Foam Mattress
Loom & Leaf Memory Foam
Premium memory foam, handcrafted in the U.S. with eco-friendly materials. Breathable organic cotton, cooling spinal gel, and layers of high-density support foam assure a cool, comfortable night’s sleep.
Memory foam firmness is measured in “indentation load deflection,” or ILD. In layman’s terms, that’s how much pressure it takes to make a 25% indent in a 4-inch piece of foam. Quality memory foam has an ILD between 10 and 50. (The higher the ILD, the firmer the mattress.) Again, check the brand’s website or reach out to customer support for the ILD if the info isn’t readily available.
ILD can be useful as a point of comparison, but keep in mind that comfort is subjective. Whether you prefer a memory foam mattress with a lower or higher ILD will depend on whether you like a softer or firmer sleep surface. (Read our guide to finding the right comfort level for you.)
Types of memory foam
Within the memory foam category, there are a few varieties.
- Traditional memory foam:Also known as viscoelastic foam, traditional memory foam is made from polyurethane, a petroleum derivative. Because of that, it can sometimes give off a chemical smell—a process referred to as off-gassing. That’s the term for what happens when volatile organic compounds (VOCs) leak out of mattress foams into the air you breathe. Common VOCs include formaldehyde, toluene, chlorofluorocarbons (CFCs), benzene, trichloroethane, and perfluorocarbons. Although there’s no evidence that off-gassing can have permanent effects on your health, it does contribute to indoor air pollution and is potentially irritating to people with chemical sensitivities or breathing issues. (Learn more about off-gassing here.)
- Gel-infused memory foam:Newer types of memory foam often contain materials that help keep you cool while you sleep, since one of the biggest complaints about memory foam is that it sleeps hot. These materials are designed to absorb and conduct heat away from the body. “The top layer of foam normally contains some form of cooling properties, whether injected with gel, graphite, or even copper,” Fish says. Cooling gel can either be mixed into the foam (infused) or applied as a layer on the surface (laminated).
- Eco-friendly memory foam:“Greener” memory foam uses plant-based ingredients, such as soybean and corn oil, in place of some of the petroleum derivatives. To find a healthier memory foam mattress, look for one that has certified low-VOC foams. One such certification is Certi-PUR. Foams that carry this label are free of CFCs, formaldehyde, phthalates, and polybrominated diphenyl ethers (PBDEs, a class of chemical flame retardants banned in the United States since 2005). As an added bonus, eco-friendly foams feature a more open-celled structure, so they are more breathable, allowing you to sleep cooler.
There are some extra features you can look for in a memory foam mattress depending on your needs and preferences.
- Lumbar support:The lumbar region of your back is located just above your hips. Lumbar support is crucial in order to preserve the natural curvature of the spine. Without it, your midsection (where most people carry their weight) will sink into the mattress and pull the spine out of alignment—a long-term recipe for back pain. Memory foam conforms to support your spine, maintaining natural alignment and alleviating back pain. Some memory foam mattresses have added lumbar support in the center third of the bed.
- Breathable fabrics:All of the layers and components in a mattress come wrapped in an outer cover. For maximum sleep comfort, the cover should be made of a material that is soft, breathable, and moisture-wicking. (Learn why organic cotton makes an excellent cover material.)
The benefits of sleeping on a memory foam mattress
There are several reasons why you might want to choose a memory foam mattress over another type of bed. Here are some of the biggest benefits of sleeping on a memory foam mattress:
- Memory foam mattresses relieve joint pain.“People with joint pain will appreciate the conforming ability of a memory foam mattress, as it gives the feeling of hugging the pressure points of the body,” says Fish. (Here are more tips for sleeping better with chronic pain.)
- Memory foam mattresses provide spinal support.Memory foam conforms to your body, helping to keep your spine in neutral alignment. This ensures you won’t wake up with a sore back.
- Memory foam mattresses limit motion transfer.With a memory foam mattress, you won’t have to worry about being woken up by a partner in the middle of the night if they get out of bed. “Because the mattress isn’t tied together in one consecutive coil system, if your partner gets up to use the restroom in the middle of the night, you aren’t going to feel a thing,” Fish says.
- Memory foam mattresses are good for allergy sufferers.Unlike innerspring mattresses, memory foam mattresses don’t have a lot of have nooks and crannies that dust mites can live in, meaning it can be a better option if you suffer from allergies.
- Memory foam mattresses are durable.A well-made memory foam mattress should last 10 to 15 years.
The drawbacks of sleeping on a memory foam mattress
There are pros and cons to every type of mattress. A memory foam mattress may not be right for you if:
- You sleep hot.By design, memory foam responds to temperature, softening as it warms and molding to your curves. While that contouring ability is one of its most beloved features, memory foam can trap and retain heat close to your body, so you might want to consider another option if you sleep hot.
- You weigh more than 200 pounds.“A memory foam mattress is better suited for sleepers under 200 pounds,” says Fish. “Anything higher and there is the potential for the sleeper to ‘bottom out’ on the mattress and not receive the necessary support.”
- You like a bouncy feeling.Innerspring mattresses are known for their responsiveness, but that’s not the case for memory foam. If you like the springy feel of a traditional mattress, you may not like the feel of memory foam. Keep in mind that that bouncy feeling is something many couples look for when it comes to sex.
Who a memory foam mattress is ideal for
One of the reasons memory foam continues to grow in popularity is that this type of bed supports a wide range of sleep styles.
Within the memory foam category, look for these features depending on your preferred sleep position:
- If you’re a side sleeper:Side sleepers benefit from snoozing on a softer memory foam mattress that keeps their spine in alignment while cushioning shoulders and hips. Look for added support in the lumbar region to protect the heaviest part of your body.
- If you’re a back sleeper:Anything too soft will cause you to sink into the bed, while anything too firm will put too much pressure on your shoulders and back, causing soreness when you wake up. If you’re a back sleeper of average weight, look for a medium-firm memory foam mattress.
- If you’re a stomach sleeper:Because memory foam molds to the shape of your body, you may not like the feel of it if you sleep on your stomach. If you’re still interested in memory foam, look for one that’s firm enough to give you the support you need. Anything from a medium-firm to firmer mattress is what you’ll want.
The right base for a memory foam mattress
Speaking of support, your mattress needs it too. A memory foam mattress is usually paired with a foundation (a.k.a. box spring) or base. It can also be paired with an adjustable base. (Mattresses that are compatible with an adjustable base will bend and flex on the base without slipping or damaging the materials or structure of the mattress.) An adjustable base can help you get into an ideal sleep position. By allowing you to elevate your head, an adjustable base can also help with snoring and acid reflux.
Learn More About Saatva’s Adjustable Base
Lineal Adjustable Base
With weightless, Zero Gravity support, the Lineal adjustable base allows you to set your ideal position for sleeping—and living—with one touch of the remote.
The fine print
If you’ve made it this far, we know you’re serious about your memory foam mattress purchase. In addition to materials and construction, there’s one more important set of criteria to review: policies around delivery, home trials, returns, and warranties. Before you hand over your credit card number, check out our Guide to Mattress Fine Print.
Here’s how our memory foam mattress compares to others on the market:
Memory Foam: Pros and Cons
Considering a memory foam mattress or similar product? Read what sleep experts say about it.
Few things feel as good as a good night’s sleep. That’s especially true if sleep seems to escape you, night after night after night.
If you’ve heard about memory foam, you may wonder if it could improve the quality ofyoursleep. Some people swear by it. Others are less enthusiastic.
What exactly is memory foam? And what are its pros and cons? Here’s information to help you decide whether memory foam is worth a try.
What Is Memory Foam?
First designed in the mid-1960s for NASA airplane seats, memory foam is made from a substance called viscoelastic. It is both highly energy absorbent and soft.
Memory foam molds to the body in response to heat and pressure, evenly distributing body weight. It then returns to its original shape once you remove the pressure.
In addition to protecting against impact, these properties make memory foam very comfortable. After its "virgin flight" for NASA, memory foam made a foray into other applications. For example, it was used as cushioning in helmets and shoes. Medicine found a use for it in prosthetics and products to prevent pressure ulcers such as seating pads for people who are severely disabled.
Then, memory foam really took off. It’s now well known for its use in pillows, mattress pads, and mattresses, which come in different densities and depths.
What Are the Benefits of Memory Foam?
Could the special properties of memory foam enhance your sleep? Sleep specialist Donna L. Arand, PhD, says that objective studies supporting the claimed benefits of memory foam — or the effects of any particular type of sleeping surface — are lacking.
This is true for a variety of reasons, she says. This type of sleep study can be expensive, if conducted independently. Or it is "chased" by a shadow of bias, if supported by industry.
Also, some sleep technology, such as memory foam, is relatively new, so it hasn’t been well studied. But perhaps one of the more difficult stumbling blocks to testing the health benefits of mattresses such as memory foam is the subjective nature of sleep. It is simply difficult to measure.
Sometimes the brain’s electrical activity, measured with an electroencephalogram (EEG), and other findings recorded during a sleep test don’t always match up perfectly with a person’s subjective experience, says Arand, who is the clinical director of the Kettering Sleep Disorders Center in Dayton, Ohio. "They might say, вЂI had a great night’s sleep,’ but the EEG parameters might not really indicate that."
Sleep is not only subjective, but preferences for sleep surfaces are individual, Arand says. "There’s quite a bit of variability between individuals in terms of what type of surface — whether it’s firm, hard, or soft — they prefer when they’re sleeping," she says. "As far as we know, there is no rhyme or reason for that."
Many of Arand’s patients who use memory foam have offered unsolicited glowing reports like these about memory foam: "I’m sleeping great." "Best sleep I’ve ever had." "I love going to bed at night." Arand says these anecdotal responses may be one-sided. That’s because she and other staff don’t ask all their patients about their sleep surfaces. "We may only be hearing the good stuff," Arand says.
Kathy R. Gromer, MD, sleep specialist with the Minnesota Sleep Institute in Minneapolis, agrees that memory foam may improve sleep. "It can, if it relieves painful pressure points," she says. But Gromer adds that memory foam doesn’t do anything for sleep apnea or other sleep-breathing disorders — and sleep disorders are the primary complaint of most her patients.
"When you lie on the memory foam, the heat from your body softens it in appropriate points," Arand says, "so this helps to support your body along the curves and natural lines of the body." Memory foam manufacturers claim this helps relieve pain and thereby promotes more restful sleep. And, though consumers often believe that very firm mattresses are best, more "giving" mattresses like these may lead to better sleep in people with back pain, according to the National Sleep Foundation.
Although there aren’t scientific data to support the hypothesis, Arand wonders whether memory foam sleep surfaces might be especially helpful for older people. For them, minimizing extra movement could reduce the number of times they awaken during the night. Being less aware of a bed partner’s movements might be an extra benefit, she adds. "Without the coiled springs, you feel your sleep partner’s movement less, and that might help, too."
What Are the Disadvantages of Memory Foam?
Gromer says that memory foam products may retain body heat, which could make them less comfortable in warm weather. However, Arand has not heard this complaint from her patients. "In our culture, most people can adjust their thermostats or blankets for the appropriate season," Arand says.
When new, memory foam can produce an odd chemical smell — a phenomenon called offgassing. To minimize this problem, the Sleep Products Safety Council, a sleep products trade group, recommends airing out the mattress or pad for at least 24 hours before putting sheets on it. "If you follow directions, the smell dissipates quickly," Arand says, "But I’ve never heard of anyone having reactions to it."
Are Memory Foam Products Safe for Young Children?
"I would strongly recommend avoiding this and similar very soft materials for use in infants’ beds," Gromer says. "That’s because soft bedding traps [carbon dioxide] and increases the risk of sudden infant death syndrome (SIDS) deaths."
NASA Scientific and Technical Information: "Forty-Year-Old Foam Springs Back With Newer Benefits."
Donna L. Arand, PhD, clinical director, Kettering Medical Sleep Disorders Center, Dayton, Ohio; research associate professor, Wright State University Boonshoft School of Medicine.
Kathy R. Gromer, MD, sleep specialist, Minnesota Sleep Institute; medical director, Respiratory Care Program, Saint Paul Technical College.
National Sleep Foundation: "Buying the Right Mattress for You."
Sleep Products Safety Council: "Mattress Odors" and "Sudden Infant Death Syndrome."
How Is Memory Foam Made?
Memory Foam Developed by NASA
The very first memory foam material was developed by NASA in the 1970s. Their intention was to try to improve seat cushioning and crash protection for airline pilots and passengers. Memory foam has widespread commercial applications, in addition to the popular mattresses and pillows you are familiar with today.
Anybody who has gone shopping for a bed, a new pillow, or even a new bicycle seat or mouse pad wrist rest in the last two decades will have encountered memory foam. This new material has been applied to a huge range of uses since its introduction to the US in 1991—from revolutionary medical uses to gimmicky new product designs. But what is it, who came up with it, and how does it work?
Though it is a relatively recent phenomenon in the US, memory foam has been around in various forms since the midpoint of the century—the first work on the polyurethane polymers that go into memory foam was actually begun in 1937 by Otto Bayer and his coworkers In 1965 the nursing staff at Lankenau Hospital tested “inert polyurethane porous foam” pads for use as bedding material, and found that they prevented “decubitus ulcers” (also known as pressure ulcers, sustained by patients who spend long amounts of time lying down), and found them to be hypoallergenic and resistant to bacteria (Kraus 1965). In the 1960s, NASA did work on materials that would serve as better cushions, and would also keep astronauts comfortable and protected from the extreme g-forces of lift off. It was then that memory foam as we know it came into being.
Memory Foam vs. Polyurethane Foam
Memory foam starts its life as polyurethane foam—a material first manufactured in the 1950s by adding water, halocarbons, or hydrocarbons to a polyurethane mix. Depending on the chemicals added and the way it is processed, polyurethane can form anything from car parts to spray liner, or in this case, one of the most comfortable sleeping surfaces the world has ever seen.
In the modern production of memory foam, a polyol is mixed with a diisocyanate and water. The foam rises like bread, with an open cell structure that helps give it its unique ability to spring back slowly from pressure. The introduction of gases into the initial solution creates a bubble matrix; vary the application of chemicals, and the size of the bubbles changes. A more open cell structure will have more give, and allow more airflow through the material.
Memory Foam Firmness
The firmness of memory foam is rated by the IFD (Indention Force Deflection), also known as ILD (Indentation Load Deflection) measuring the force in pounds required to make a 25% indentation in a 4 inch thick foam square. Also important in measuring the “softness” of a foam is the density. Foam densities range from 1-7 lbs, but a good-quality foam will usually be at least 4 and usually 5 lbs. A foam with a high density, but low ILD may still feel firm when compressed, especially in a lower room temperature. The density together with the IFD/ILD and the resilience will determine the softness, firmness, and life-span of the foam. Foam that is lower density will more readily conform to pressure, whereas higher density foam (usually 5-lb. or above) molds itself to contours when warmed by body heat.
Major production of memory foam did not begin until NASA released it into the public domain in the 1980s.Fagerdala World Foamstook up the challenge of producing this somewhat difficult product, and in 1991 produced the “Tempur-Pedic Swedish Mattress.” Today numerous companies around the world produce visco-elastic memory foam, which gives consumers increased variety and price range. Unfortunately, it also increases the risk of purchasing cheaply-made foams that may deteriorate over time. Not all memory foam is made equal, as many of the overseas manufacturers work at reducing the cost of memory foam by adding in other “filler” type ingredients that reduce the quality and potentially add toxicity to the formulation. The real problem with overseas foam is the lack of quality standards that have been created in the United States.