What's Inside a Mattress (And What Actually Determines Quality)

I've seen mattresses from both ends. I spent years building them on a factory floor — laying up spring units, attaching foam layers, hogtying covers and sending them off to be sewn. Now I run a mattress recycling company that's torn apart over 1.15 million mattresses since 2011.

That perspective — watching mattresses get built and then seeing what's left of them 5, 10, or 20 years later — has taught me something the mattress industry doesn't want you to know: most mattresses are made from the same handful of materials, just marketed a hundred different ways.

What I see every day — mattresses arriving at our facility and getting torn apart

The difference between a mattress that lasts three years and one that lasts fifteen comes down to material quality you'll never see in a showroom. Foam densities, coil tempering, cover construction — details manufacturers deliberately hide behind proprietary names and marketing language.

This article is everything I wish consumers knew before buying a mattress.

The Mattress Industry's Best-Kept Secret: It's All the Same Stuff

Here's something that might surprise you: despite all the fancy names and proprietary technologies you see advertised, there are really only a few basic materials that go into mattresses.

On the factory floor, I worked with the same core components over and over:

• Polyurethane foam (what the industry just calls "foam")
• Memory foam (a denser, slower-responding version of polyfoam)
• Latex foam (rubber-based, either natural or synthetic)
• Steel coils (in various configurations)
• Fiber batting and cover materials

That's basically it. What changes is the quality of these materials and how they're combined.

The same basic materials, over and over — foam, springs, fiber, fabric

When a mattress company advertises their exclusive "CloudComfort Foam" or "DreamSupport Technology," they're almost certainly talking about polyurethane foam — just with a marketing name attached. Memory foam gets rebranded constantly too. One company's "GelFlex Memory Foam" is another company's "CoolAdapt Foam" is just... memory foam, possibly with some gel beads mixed in.

The only genuinely new innovations I've seen in my career are:

1. Memory foam itself — which was developed by NASA in the 1970s and hit the mattress industry in the 1990s
2. Purple's hyper-elastic polymer grid — truly a different material, though whether it's better is debatable
3. Air chamber systems like Sleep Number — where inflatable bladders replace traditional support cores

Everything else? It's the same materials I was working with on my dad's factory floor, just packaged differently.

The Two Systems That Make Up Every Mattress

Every mattress, regardless of what the marketing says, has two basic parts:

The Support Core — The bottom layer that bears your body weight. This is either a steel coil unit or a thick layer of high-density foam (usually 6-8 inches of firm polyfoam in all-foam mattresses). I've written a detailed guide on support layers that covers exactly why this layer determines mattress lifespan more than anything else.

The Comfort Layers — The top 2-4 inches of softer material that cushion your body and provide pressure relief. This is where most mattresses fail first. I've written a detailed guide on comfort layers covering memory foam, latex, and quilting — which materials last and how they break down.

When I was building mattresses, the process was pretty much the same regardless of the style:

1. Lay up the support core (spring unit or base foam layer)
2. Attach each layer of comfort foam on top
3. Hogtie the cover around everything
4. Send it to be sewn up

The materials changed depending on whether we were building a budget mattress or a premium one, but the process was the same. And here's what I learned: what you put into those layers — the quality of the materials — determines everything about how long that mattress will last.

The Different Types of Mattresses (And Why They're More Similar Than You'd Think)

Innerspring Mattresses

The traditional design. Steel coils provide support, foam and fiber layers on top provide comfort.

When I built innerspring mattresses, I'd lay up the coil unit first, then attach layers of polyfoam and fiber batting on top before the cover went on. The coil unit might be Bonnell coils (the old hourglass-shaped ones connected with spiral wire), offset coils, or pocketed coils (individually wrapped springs).

What I see in recycling: The coil unit is usually in better shape than the foam layers above it. Unless it's a really cheap mattress with thin-gauge wire, the springs typically outlast the comfort layers by years. (I wrote more about this pattern in my research on 1.15 million mattresses.)

Memory Foam Mattresses

All-foam construction with memory foam comfort layers over a firm polyfoam support core.

These became popular with the bed-in-a-box companies because foam compresses well for shipping. When I built all-foam mattresses, there was no coil unit — just progressively firmer layers of foam from top to bottom. According to the Sleep Foundation, memory foam mattresses now make up a significant portion of the market.

What I see in recycling: Body impressions are extremely common. The memory foam comfort layer molds to the sleeper's shape, and on cheaper mattresses, it stops rebounding within a year or two. The base foam is usually still fine — it's the comfort layers that fail.

Hybrid Mattresses

Pocketed coil support with foam comfort layers — combining elements of both previous types.

Hybrids are popular now because they theoretically give you the support of springs with the pressure relief of foam. When I built hybrids, the pocketed coil unit would go down first, then usually a transition layer of firmer foam, then memory foam or latex on top.

What I see in recycling: These can go either way. Good hybrids hold up well because the pocketed coils share the load with the foam. Cheap hybrids fail in all the ways both innersprings and foam mattresses can fail — you get the worst of both worlds.

Latex Mattresses

This is my personal favorite, and I only sleep on mattresses with latex comfort layers.

Latex foam comes from rubber trees (natural latex) or is made synthetically (synthetic latex, or SBR). Some mattresses are all-latex; others use latex just in the comfort layers over a coil or foam support core.

What I see in recycling: Latex holds up better than any other foam. We tear apart 15-year-old mattresses and the latex layers still have bounce. The polyfoam around them is shot, the cover is worn, but the latex? Still resilient. There's a reason I sleep on it.

Air Mattresses (Sleep Number Style)

Air chambers replace the traditional support core. A pump inflates or deflates the chambers to adjust firmness.

I didn't build these — they're a different manufacturing process entirely. But we recycle them. The air chambers are surprisingly durable; the foam comfort layers on top fail the same way any foam does.

What Actually Determines Quality: The Materials No One Tells You About

Foam Density: The Single Most Important Spec You'll Never See Advertised

Here's what I learned building mattresses that the industry doesn't want consumers to know: foam density is the primary predictor of how long a mattress will last, and it's the one specification manufacturers almost never disclose.

Density is measured in pounds per cubic foot (PCF). It's not the same as firmness — a foam can be soft AND dense, or firm AND low-density. Density is about how much material is packed into the foam, which determines how long those cell walls hold up under repeated compression.

On the factory floor, here's what I saw going into different mattresses:

For polyurethane foam (support layers):

• Budget mattresses: 1.2-1.5 lb density
• Mid-range mattresses: 1.5-1.8 lb density
• Premium mattresses: 1.8-2.5+ lb density

For memory foam (comfort layers):

• Budget mattresses: 3-3.5 lb density
• Mid-range mattresses: 4-4.5 lb density
• Premium mattresses: 5+ lb density

The material cost difference between 1.5 lb foam and 2.0 lb foam might be $30-50 per mattress. But the lifespan difference is years. And here's what gets me: you'll never see this number on a mattress tag.

What I See Picking Up Mattresses

The correlation between foam density and mattress condition when we pick them up is absolute. After recycling over a million mattresses, the pattern is unmistakable:

Low-density foam mattresses after just a few years — visible body impressions, collapsed support

Low-density foam mattresses (usually budget priced): Visible body impressions within 6-12 months. By year 2-3, there are deep valleys where the sleeper lies. The foam has completely broken down — cells have collapsed, the material doesn't spring back.

High-density foam mattresses (usually premium): Still look good after 5-8 years. Eventually they develop impressions too, but the timeline is measured in years, not months.

When we tear apart a mattress and the comfort layer just crumbles in our hands, we know it was cheap foam. When it still has some bounce after a decade of use, we know somebody paid for quality.

The Four Ways I See Mattresses Fail

After picking up mattresses for over a decade, the failure patterns are consistent. Here's what kills mattresses:

1. Support System Failure (Sagging)

Ever notice you roll toward the center of your mattress? That's support system failure.

What causes it: The spring unit breaks down and stops providing even support across the surface. Center coils — which bear the most weight — fail first. Or on all-foam mattresses, the base layer compresses and doesn't bounce back.

What it looks like: The whole mattress sags in the middle. You feel like you're sleeping in a hammock. Two people roll toward each other whether they want to or not.

The quality factor: Cheap coil units use thinner-gauge wire (15-18 gauge — remember, lower gauge numbers mean THICKER wire). They can't support weight long-term. Premium units use 12-14 gauge tempered steel that maintains tension for years. Same goes for base foam — higher density holds up, lower density compresses permanently.

2. Edge Support Failure

Ever sit on the edge of your mattress and feel like you're going to slide off? That's edge failure.

What causes it: The perimeter of the mattress can't support concentrated weight. Edge coils collapse, foam around the perimeter compresses, and the edge becomes a drop-off.

What it looks like: You can feel a soft, unstable zone around the edges. Getting into and out of bed becomes harder because the edge sinks dramatically under your weight.

The quality factor: Premium mattresses have reinforced edges — sometimes extra-firm foam encasement, sometimes heavier gauge coils around the perimeter, sometimes steel wire rails. Budget mattresses skip all of that.

3. Body Impressions (Comfort Layer Failure)

Look at an older mattress from the side. See those dips where people usually sleep? Those are body impressions.

What causes it: The comfort layers — the top 2-4 inches of softer foam — break down from repeated compression. The foam cells collapse and stop rebounding. Over time, permanent impressions form in the shape of the sleeper.

What it looks like: Visible valleys in the surface. The mattress no longer feels flat — there are dips at the hip and shoulder positions where most of the body's weight concentrates.

The quality factor: This is 100% about foam density. Low-density foam (1.5 lb polyfoam, 3 lb memory foam) develops impressions within months. High-density foam (2.0+ lb polyfoam, 5+ lb memory foam) takes years to break down.

Body impressions will eventually happen to almost any mattress. The question is whether they happen in 6 months or 10 years.

4. Cover Failure (And the Fiberglass Problem)

A low-quality cover starts to shred and expose what's underneath. Or the zipper breaks and you can't remove the cover anymore.

What causes it: Cheap fabric. Low GSM (grams per square meter) material that pills, thins, and tears. Weak zippers that jam or pull away from the stitching.

What it looks like: You can see the foam through worn spots in the cover. Pilling all over the surface. Broken zippers.

Why this matters more than you'd think: When the cover fails on a cheap mattress, you might expose the fiberglass fire barrier underneath. I can't tell you how many times we've torn open a mattress with a fiberglass fire sock and found particles everywhere — disintegrating, getting into the air, likely being breathed in by whoever slept on that mattress.

The Fiberglass Fire Barrier Problem

This is one of the worst things I've seen in my career.

Here's the background: Mattresses used to catch fire easily once they reached a certain temperature. So regulations came in requiring mattresses to resist flames. First, manufacturers used flame retardant sprays — but those chemicals turned out to be toxic, sometimes more harmful when burned than just letting the mattress combust. (Honestly, the whole thing never made much sense to me — if the mattress is hot enough to combust, the person in the house is probably already in serious trouble. But regulations are regulations.)

So the industry moved to fire socks — fabric barriers that go around the foam layers and underneath the cover. These barriers need to resist heat, and fiberglass is cheap and effective at that.

The problem: Many lower-quality firesocks — especially on mattresses made overseas — use fiberglass material that doesn't stay contained. Over time, or when the cover is removed or fails, those fiberglass particles get everywhere.

I've seen it firsthand. We tear open a mattress and the fire sock is disintegrating. Fiberglass particles are all over the foam, probably all over the bedroom of whoever owned this mattress. We're wearing respirators and protective suits. The customer was sleeping on it, breathing it in, getting particles in their skin.

This has become a huge issue lately. Major companies have faced class action lawsuits over fiberglass contamination. Families have had to spend tens of thousands of dollars on remediation after fiberglass from their mattress got into their HVAC system and spread through their home.

The alternative: Premium mattresses use wool, silica-treated rayon, or Kevlar as fire barriers. These materials are naturally flame-resistant and don't present contamination risks. But they cost more, so budget manufacturers skip them. (I cover the fiberglass nightmare in more detail in my 1 million mattresses article.)

My Take on Latex (And Why It's My Favorite)

I want to be transparent about something: I only sleep on mattresses with latex comfort layers. It's my personal preference, based on what I've seen building and recycling mattresses.

Latex foam — whether made from natural rubber tree sap or synthetic rubber — holds up better than any other comfort material. When we tear apart a 15-year-old mattress that used latex, the latex layers still have bounce. Everything else around them has broken down, but the latex is still resilient.

Why latex performs differently: The cell structure is fundamentally different from polyurethane foam. Vulcanized rubber creates stable molecular bonds that maintain elasticity for decades rather than years. It's also naturally more breathable than memory foam, so it doesn't trap heat the same way.

About the "organic" and "natural" claims: I'm skeptical of the marketing here. Yes, natural latex comes from rubber trees. Yes, it has fewer chemicals than polyurethane or memory foam. But it's still highly processed foam. The vulcanization process that turns liquid rubber into durable foam requires sulfur, zinc oxide, and various other compounds. Even the most natural latex is only 95-97% botanical rubber.

Look for GOLS certification (Global Organic Latex Standard) if "organic" matters to you — that's the only real standard. But understand that "organic latex" is still a manufactured industrial product, not something straight from nature.

Why You Can't Tell Quality in a Showroom

Here's the fundamental problem with mattress shopping: you can't see or feel the quality factors that actually matter.

In my years building mattresses, I'd make budget mattresses that felt nearly identical to premium mattresses on day one. The difference was in the materials you couldn't see — foam density, coil gauge, cover weight. You'd need to sleep on them for months before the difference showed up.

Ten minutes in a showroom tells you almost nothing about durability. That firm foam might be low-density (cheap) and will collapse in months. That spring unit might feel great but use thin-gauge non-tempered wire that will deform by year two. The cover might feel plush but be low-GSM material that shreds.

The industry relies on this opacity:

• Foam density is almost never disclosed
• Proprietary names obscure the fact that all mattresses use the same basic materials
• "Premium foam" and "luxury support" have no standardized definitions
• The same mattress sells under different names at different retailers to prevent price comparison

You're basically buying blind. And manufacturers like it that way.

What to Actually Look For

Based on everything I've seen — building mattresses and recycling them — here's what I tell people:

Ask for foam density numbers. Not firmness, not thickness — density (PCF). If the manufacturer won't tell you, that's a red flag. Look for 1.8+ lb for polyfoam, 4+ lb for memory foam, and avoid anything that won't disclose.

Check the coil specifications. For innerspring and hybrid mattresses, look for 14 gauge or thicker (lower gauge number = thicker wire). Tempered steel is better than non-tempered. Pocketed coils are generally better than Bonnell for motion isolation.

Investigate the fire barrier. Ask specifically what material is used. If it's fiberglass, or if the answer is vague, be cautious. Look for wool, silica-treated rayon, or Kevlar.

Consider the cover quality. This is harder to assess, but look for thick, tightly woven fabric. Cheap covers pill and thin quickly.

Look at warranties critically. A 10-year warranty sounds good until you read the fine print. Most require a 1.5-inch body impression before you can make a claim — which means your mattress can have a noticeable sag and still not qualify for replacement.

Be wary of bed-in-a-box. The compression required for shipping can damage foam cells. These companies also tend to use lower-density foams because they compress more easily. That doesn't mean all boxed mattresses are bad — but it does mean you should be more skeptical. (I discuss the bed-in-a-box problem in more detail in my 1 million mattresses article.)

Expected Lifespans Based on Quality

This is what I've seen over years of picking up mattresses at the end of their useful life:

Budget mattresses (under $500): 2-5 years. Body impressions and sagging appear within the first year or two. By year 3-5, the mattress is clearly worn out.

Mid-range mattresses ($500-1,500): 5-8 years. Slower degradation, but the comfort layers still break down faster than the support system.

Premium mattresses ($1,500+): 8-15+ years with quality materials. Natural latex mattresses from good manufacturers can last 15-25 years.

Keep in mind: these are averages based on what I see. Body weight matters — heavier sleepers will break down foams faster. Sleeping position matters. A mattress used every night wears differently than one in a guest room.

The Bottom Line

After years building mattresses and over a decade recycling them, here's what I know:

Most of the mattress industry is marketing. The same basic materials get repackaged under hundreds of proprietary names. "Exclusive technology" usually means commodity foam with a trademark.

The things that actually determine quality — foam density, coil gauge, fire barrier material, cover construction — are the things manufacturers hide. They'd rather talk about cooling gel and plush pillowtops than disclose the specs that predict durability.

Cheap mattresses fail in predictable ways: body impressions, sagging, edge collapse, cover deterioration. Premium mattresses use better materials and last longer. The material cost difference might be $50-100; the lifespan difference is measured in years.

Demand density numbers. Find out what's in the fire barrier. Be skeptical of marketing language. A manufacturer who's confident in their materials will disclose them. One who's hiding behind proprietary names probably has something to hide.

I've seen over a million mattresses at the end of their lives. The ones that held up were built with quality materials. The ones that fell apart early were built with cheap materials dressed up with marketing. The pattern is that simple.

1.15 million mattresses and counting — this is what I've learned