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Foam is practically everywhere: in our beds, our couches, our shoes, and our shipping boxes. When you're shopping for it, you're usually choosing between two main families. There's open-cell foam, which is soft and breathable (think memory foam or latex), and closed-cell foam, which is firm and water-resistant (like neoprene or EVA). Which one is right for you? It all depends on what you're trying to do—whether that's adding some cushion, absorbing an impact, or making something float.
We put this guide together to cover every foam you’re likely to come across. We’ll show you exactly what each one is good for and answer the questions people ask us the most. We’ve broken it down into two main sections: Part one is all about everyday uses (think comfort, crafting, storage, and keeping things safe). Part two shifts gears to construction and industrial foams, like spray foam and rigid insulation, which do a completely different kind of job.
Every type of foam is graded by a handful of measured properties. The two most common are density and firmness, but they are incredibly easy to mix up. The key difference? Density predicts how long the foam will hold up over time, whereas firmness (or ILD) describes how soft or hard it feels when you press on it. Because they measure two different things, a soft foam can have high density, and a firm foam can have low density. Let's take a look at the actual numbers you'll spot on a spec sheet.
The weight of raw foam material in a cubic foot. More material means the foam holds its shape and resists sagging for more years. It says nothing about how soft or firm the foam feels.
Indentation Load Deflection: the pounds of force a 50-square-inch plate needs to compress a standard 4-inch-thick foam sample by 25 percent of its thickness. A higher ILD feels firmer, a lower ILD feels softer. This is the number you tune to get the sit you want.
Also called sag or compression modulus: the 65 percent ILD divided by the 25 percent ILD. A higher ratio means the surface gives softly but the foam resists bottoming out. HR foams score high here.
Measured with a ball rebound test: drop a steel ball and see how high it bounces back. High resilience feels lively and responsive like latex or HR foam; very low resilience is the slow, dead feel of memory foam.
These are the flexible and specialty foams you're most likely shopping for. You'll recognize these materials from everyday items like cushions, mattresses, protective cases, cosplay builds, acoustic panels, and outdoor gear. We've organized them into three main groups based on how they’re used: Comfort foams, closed-cell foams and specialty & utility foams.
Polyurethane foam is the workhorse of the foam world and the material inside most furniture made in the last 60 years. It is an open cell foam produced in a huge range of densities and firmness levels, from soft bargain-grade foam to dense, long-wearing upholstery grades — available at FoamOrder as custom-cut polyurethane foam or in upholstery sheets. It is affordable, easy to cut and glue, and simple to match to a specific feel, which is why it remains the default choice for seating.
Sitting on it feels plush and immediate — it gives quickly under your weight and springs back, though softer grades can start to feel a little dead after years. To the hand it is the familiar spongy cushion foam everyone knows.
For seat cushions that get daily use, choose high density polyurethane foam of at least 1.8 pounds per cubic foot, and ideally 2.5 pounds or higher for the longest life. Density measures durability, not firmness. Firmness is a separate rating (ILD), so a high density foam can be made soft, medium, or firm.
High resilience foam is the premium tier of polyurethane. Its cell structure is more irregular and latex-like, which gives it a springy, supportive feel and a much higher support factor than conventional foam. HR foam typically comes in densities of 2.5 to 3.0 pounds per cubic foot and can outlast conventional foam by years in daily-use seating. FoamOrder cuts it to size as high-density foam.
A livelier, more buoyant sit than conventional foam — it pushes back as it cradles, so you feel supported on top rather than sunk in. Under the hand it has a springy, almost latex-like bounce.
HR foam recovers faster, supports more evenly, and resists softening and sagging far longer than conventional polyurethane. The tradeoff is cost: HR foam runs noticeably more per cushion, but for furniture you sit on every day it is usually the cheaper option over a ten year span.
Memory foam is a viscoelastic type of polyurethane originally developed for NASA to cushion test pilots. It softens in response to body heat, contours slowly to your shape, and recovers slowly when you move, which is what produces its signature pressure relief. That same slow response is why it behaves very differently from regular foam in seating applications. FoamOrder's house version is PostureSense memory foam.
Press it and your handprint slowly appears, then fades. It softens with body heat and molds to your shape, giving a cradled, weightless, slow-sinking feel with almost no push-back — you settle into it rather than sit on it.
Not by itself. Under concentrated, sustained sitting weight, memory foam compresses fully and bottoms out, and body heat makes it softer the longer you sit. It works best as a 1 inch comfort layer glued over a firm HR foam base, which gives you the contouring feel with real support underneath.
Gel memory foam is standard viscoelastic foam with gel beads or swirls mixed in to pull heat away from the body. The gel gives the foam a cooler first touch and, in some formulations, a slightly quicker recovery than traditional memory foam. Everything else about it behaves like regular memory foam.
The same slow, contouring melt as memory foam, but noticeably cool to the touch when you first lie down as the gel pulls heat from your skin. That cool feeling fades as the foam warms to you.
Somewhat, and mostly early in the night. Gel absorbs body heat on contact but eventually saturates, so the effect fades over hours. Airflow matters more for all-night cooling: ventilated covers, breathable fabrics, and open cell comfort layers do more than gel alone.
Latex foam is made from natural rubber tree sap, synthetic rubber, or a blend, and is what most people historically meant by the phrase foam rubber. It is buoyant, instantly responsive, extremely durable, and naturally resistant to dust mites and mold. Natural and organic latex is the go-to for eco-conscious buyers, and it is the core material in FoamOrder's organic cushions and latex mattresses. The tradeoffs are weight and price: latex is heavy and costs more than polyurethane.
A distinctively lively, buoyant bounce — it responds instantly and pushes back the moment you lift away, with none of the slow sink of memory foam. In the hand it feels dense, springy, and substantial rather than squishy.
Dunlop latex is denser, firmer, and more supportive, which makes it the better choice for seat cushions and mattress cores. Talalay latex is lighter, softer, and more consistent from edge to edge, which is why it shows up in pillows and plush comfort layers. Both can be made from natural latex, but only Dunlop can be certified organic (GOLS): the Talalay process can't earn that certification and often blends in some synthetic latex. Either one, when it is natural latex, is naturally hypoallergenic and resistant to dust mites and mold.
Dry fast foam is an open cell polyurethane that has been reticulated, meaning the cell walls are blown open into a net-like structure. Water pours straight through it instead of soaking in, so a drenched cushion can drain and air-dry in hours, and mold and mildew have nowhere to take hold. It is the standard recommendation for any cushion that lives outside, and it is what FoamOrder uses in outdoor foam cushions.
Firmer and more open than a normal cushion, with a slightly coarse, netted surface you can feel through thin fabric. Squeeze a wet piece and water pours straight through it instead of holding in your hand.
Yes, if the cushion uses dry fast foam with a breathable, solution-dyed cover. Rain drains through the foam and the cushion dries quickly, especially if you tilt it on edge. During long wet stretches or over winter, it is still smart to store cushions to protect the fabric and stitching.
Rebond foam, also called bonded foam or chip foam, is made by shredding scrap polyurethane and pressing the chips back together with adhesive. The result is a dense, heavy, very firm foam with a distinctive multicolor confetti look. It is too hard for lounging comfort on its own, but nothing beats it for firm, high-traffic padding on a budget. FoamOrder cuts it to size as recycled rebond foam.
Hard, dense, and unforgiving — it barely gives under a hand and feels solid and heavy, with a lumpy, chip-flecked texture you can feel through a thin cover. This is padding you stand or kneel on, not something you sink into.
Only where you want very firm seating, such as commercial booths, church pews, or bases that will be topped with a softer layer. As a standalone lounge cushion it feels hard and unforgiving, so most furniture applications pair it with 1 to 2 inches of softer foam on top.
Shredded foam is polyurethane or memory foam chopped into small pieces and used as loose fill. It creates a soft, moldable, scrunchable cushioning that conforms however you push it, which solid foam cannot do. It is also one of the most economical fills available since it makes use of production offcuts. FoamOrder sells it by the bag as shredded foam.
Loose and scrunchable, like a sack of soft crumbs — it shifts and molds around your hand or body, and you can punch, fluff, or scoop it into whatever shape you want. It never holds one firm surface the way solid foam does.
Often yes, which is one advantage over solid foam. Many shredded foam pillows can be machine washed on gentle with cold water, then air dried completely before use. Always check the care tag, and never machine wash or dry a solid foam insert, since agitation tears the foam structure apart.
Egg crate is a surface profile, not a chemistry: it is polyurethane or memory foam cut into a peak-and-valley pattern. The peaks compress easily for a softer feel, the valleys create airflow, and the shape spreads pressure and scatters sound. Cutting one sheet into two interlocking convoluted sheets also makes it economical.
The bumpy ridges compress softly and unevenly, giving a gentle, almost massaging feel under you, while the valleys move air so the surface never feels hot or dense. Run a hand across it and you feel the peaks give first.
The bumpy side goes up, facing you. The peaks cradle the body, distribute pressure, and let air circulate through the valleys, which keeps the surface cooler. The flat side sits against the mattress or case bottom to keep the topper stable.
Fire retardant foam is polyurethane engineered or treated to meet specific flammability standards rather than a separate chemistry. Different grades target different codes: California TB 117-2013 covers residential smolder resistance, TB 133 and similar standards cover public occupancies, and aviation foams meet FAR 25.853. Commercial projects frequently require documented compliance, which is why FoamOrder stocks dedicated fire retardant foam.
It feels just like the polyurethane it is based on — plush or firm depending on the grade. The flame-resistant treatment is invisible to the touch, so you would never know it was rated just by sitting on it.
Whenever the local code, fire marshal, or the venue's insurer requires it, which is common in restaurants, hotels, theaters, healthcare facilities, and public buildings, plus aviation and commercial marine settings. Residential upholstery in the US follows the TB 117-2013 smolder standard. When in doubt, ask the authority having jurisdiction before ordering.
Polyethylene is the most common closed cell foam: stiff, lightweight, water resistant, and highly consistent from sheet to sheet. Because its sealed cells do not absorb water or compress permanently under normal loads, it excels at protecting things rather than cushioning people. It is one of several closed cell foams FoamOrder stocks.
Stiff, dense, and barely compressible — press it and it hardly moves, with a smooth, slightly waxy closed skin. It feels more like a firm board than a cushion, which is exactly why it protects rather than pampers.
Effectively yes. Its closed cells cannot absorb water, so it floats indefinitely, dries with a wipe, and resists mold and mildew. Only a trace of surface moisture clings to the outer skin, which is why PE is the default for marine flotation and wet-environment padding.
Cross-linked polyethylene is PE whose polymer chains have been chemically or radiation bonded to each other. The cross-linking produces finer cells, a smoother and almost rubbery surface, and better resistance to chemicals, heat, and repeated impact than standard PE. FoamOrder sells it as cross-poly foam.
A similar firm, closed-cell feel to standard PE, but smoother and almost rubbery in the hand, with a finer, softer skin that glides over surfaces instead of scuffing them. Still firm to press, just more refined to touch.
Cross-linking gives XLPE finer cells, a smoother non-abrasive skin, and more toughness under repeated compression, heat, and chemical exposure. It costs more than standard PE, so choose XLPE when surface finish, skin contact, or long-term durability matter, and standard PE for basic packaging and flotation.
EVA (ethylene-vinyl acetate) is a closed cell foam with a soft, rubbery, almost leathery feel, sold in everything from thin craft sheets to thick interlocking floor tiles. It heat-forms at low temperatures, sands to smooth curves, and takes paint and sealers well, which has made it the signature material of the cosplay world. FoamOrder carries EVA foam sheets along with a dedicated cosplay foam selection.
Soft, rubbery, and slightly grippy — it bends and flexes easily in the hand with a smooth, leathery surface that feels warm and pliable rather than hard. Underfoot on a mat it has a cushioned, springy give.
Finished EVA foam is broadly considered safe for wearables, mats, and props. Some cheap imported play mats were flagged years ago for formamide residues, so buy from reputable suppliers that test their material. When sanding, heat-shaping, or hot-wire cutting EVA, work in a ventilated space and wear a respirator, since dust and fumes are the real exposure risk.
Volara is a brand of irradiation cross-linked polyethylene made in thin rolls, typically 1/16 to 1/2 inch thick. Its cells are so fine and uniform that the surface feels smooth and almost skin-like, and it thermoforms, die-cuts, and laminates cleanly. When a project needs padding that looks finished and will never scratch what it touches, Volara is the usual answer.
Thin, smooth, and almost skin-like — it feels finished and silky under a fingertip, with a fine sealed surface that glides rather than grabs. Being so thin, it pads and lines rather than cushions any real weight.
Volara is used wherever thin, clean-looking, non-abrasive padding matters: lining cases for instruments and optics, padding medical devices and braces, gasketing, and as a foam backing laminated under vinyl or fabric. Its smooth sealed surface also wipes clean, which suits medical and food-adjacent uses.
Flotex is FoamOrder's flexible closed cell foam, softer and more pliable than rigid polyethylene boards while keeping the water resistance and buoyancy of a closed cell structure. That combination makes it comfortable enough to sit or exercise on and safe to soak. See the Flotex foam page for available sheet sizes.
Softer and more pliable than a rigid foam board but still closed and water-shedding — it has a gentle, cushioned give underhand or underfoot and feels light and buoyant, comfortable enough to sit or kneel on and safe to soak.
Yes. Its sealed cells trap air permanently, so it stays buoyant and never waterlogs, which is why it is used in flotation boat cushions and life preserver applications. Note that finished life-saving devices must meet their own certifications; the foam provides the buoyancy, not the rating.
Neoprene is a closed cell synthetic rubber foam, usually laminated with stretchy nylon fabric on one or both sides. It insulates even when wet, stretches and recovers, and shrugs off water, oils, UV, and many chemicals. FoamOrder stocks neoprene in over 100 color and thickness combinations.
Stretchy, cushioned, and grippy, with a soft fabric face that flexes and springs back — the unmistakable wetsuit feel. It is warm and slightly tacky against skin and hugs whatever it wraps.
The foam itself is highly water resistant because its closed cells cannot absorb water, and it keeps insulating when wet. Whether a finished item is fully waterproof depends on construction, since fabric faces and stitched seams can wick. Wetsuits actually work by trapping a thin layer of water that your body warms.
Acoustic foam is open cell polyurethane cut into wedge, pyramid, or egg crate profiles that trap and dissipate sound waves. It absorbs mid and high frequencies, which kills echo and reverb inside a room and makes voices and recordings dramatically clearer.
Light and soft with a slightly crumbly, open surface — the sculpted wedges squash easily under a fingertip and feel airy rather than dense. It is made to be looked at and heard, not sat on.
No, and this is the most misunderstood point in home audio. Acoustic foam absorbs reflections inside a room, improving clarity and reducing echo, but it does almost nothing to stop sound traveling through walls. True soundproofing requires mass, air sealing, and decoupling, like added drywall layers and sealed gaps.
Melamine foam is an ultra-lightweight open cell foam made from melamine resin rather than polyurethane. It combines excellent sound absorption with a Class A fire rating, which is why it shows up in commercial acoustic panels and HVAC lining. Its other life is stranger: the micro-fine structure becomes abrasive when wet, which is the entire secret behind the Magic Eraser.
Surprisingly light and dry, like a firm, extremely fine sponge. Dry, it feels soft; wet it and rub, and the surface turns faintly gritty and drags like ultra-fine sandpaper — the trick behind its cleaning power.
Yes. A Magic Eraser is plain melamine foam, and unbranded melamine sponges work the same way. The wet foam acts like extremely fine sandpaper that scrubs marks off at a microscopic level, which also means you should test it first on glossy paint, stainless, and delicate finishes.
Charcoal packing foam is open cell polyurethane in the familiar dark gray color that lines equipment cases everywhere. It is soft enough to cradle gear, cuts cleanly for custom cavities, and pairs with a convoluted lid layer for all-around protection. The same foam, cut into large blocks, is what fills gymnastics and trampoline pits. FoamOrder sells both packing foam sheets and foam pit cubes.
Soft and cushiony with a fine, slightly velvety open surface — it gives gently when you press gear into it and cuts cleanly, cradling objects without hard spots. Lighter and airier than it looks.
Charcoal polyurethane is the right choice for most gear: cut cavities in a solid base layer and add a convoluted sheet in the lid. Step up to closed cell polyethylene for heavy items, sharp edges, or cases that see repeated hard impacts, since PE resists crushing far better.
Floral foam is a soft, crumbly phenolic-based foam designed to do one job: hold flower stems exactly where you place them. The wet type soaks up water like a sponge to keep fresh stems hydrated for days, while the dry type anchors silk and dried arrangements. It is a single-use material, and it crumbles rather than compresses.
Soft, crumbly, and (when wet) cool and damp like dense cake — a stem pushes in with almost no resistance and stays exactly where you place it. It breaks apart rather than compressing and leaves a fine residue on your fingers.
Traditional floral foam is not. It is a phenolic plastic that breaks down into microplastic fragments, which is why many florists are shifting to reusable mechanics like chicken wire and pin frogs. Newer bio versions degrade only under specific composting conditions, so check the manufacturer's claims carefully.
These foams solve construction, insulation, and industrial problems rather than comfort ones. FoamOrder does not sell them, but if you are researching foam you will run into them constantly, and knowing the differences saves expensive mistakes at the hardware store.
A few more foam types exist for narrow jobs, each tuned to one demanding environment:
Different chemistries, same trick: trap gas in a solid, and the material gets lighter, softer, or more insulating than the solid alone.
Nearly all foam is made by trapping gas inside a liquid polymer at the instant it turns solid. For polyurethane — the foam in most cushions and mattresses — that happens through a fast chemical reaction you can tune to produce almost any feel.
Polyurethane begins as two liquids: polyols (long-chain alcohols) and diisocyanates (usually TDI or MDI). Add catalysts and surfactants and they react within seconds, cross-linking into a solid polymer. Changing the polyol, the isocyanate, and the additives is how makers move a foam from soft and flexible to hard and rigid.
At the same moment, a blowing agent forms the bubbles. Water is the common one: it reacts with the isocyanate to release CO₂ that foams the mix as it cures. Whether those bubble walls burst or stay sealed decides everything — open-cell foam keeps an interconnected, breathable network that compresses and rebounds, while closed-cell foam traps gas in sealed pockets for stiffness, buoyancy, and insulation.
Latex is whipped rubber-tree sap that is then vulcanized; polyethylene and EVA are melted thermoplastics expanded with gas; and EPS and EPP are pre-expanded plastic beads fused together with steam. Same trick — gas trapped in a solid — with different chemistry.
Commercial buyers and engineers work from measured, repeatable standards. Most flexible-foam properties are tested under ASTM D3574, the standard test methods for flexible cellular urethane; rigid and closed-cell insulation carries its own thermal and fire standards. Here is what each term means and how it is measured.
Most foam is a petroleum product, and the industry is under real pressure to lower its footprint. A few shifts are already changing what shows up on spec sheets.
Soy and other plant-based polyols now replace part of the petroleum polyol in many polyurethane foams, trimming fossil inputs while performing much the same on the couch or bed.
Programs like CertiPUR-US verify foam is made without certain chemicals and meets low-VOC limits for indoor air — meaningful for anything you sleep or sit on every day.
EPS is recyclable where facilities accept it, and flexible polyurethane scrap gets a second life as rebond foam for carpet pad and mats. Closed-cell and thermoset foams remain much harder to recycle.
Natural latex from rubber trees (GOLS organic) and plant-fiber fills offer genuinely renewable alternatives for buyers who put low impact first.
The greenest foam is often the one you never replace. A dense HR or latex cushion that lasts 15 years beats cycling through cheap foam three or four times — durability is sustainability.
Foam is surrounded by half-truths. Here are the ones we correct most often.
High density means high firmness.
Density measures how much material is in the foam, which predicts durability. Firmness (ILD) is a separate rating — a high-density foam can be built soft, medium, or firm.
All memory foam sleeps hot.
Traditional memory foam can trap heat, but gel infusions, open-cell structures, and ventilated covers make many modern versions sleep neutral to cool.
Acoustic foam soundproofs a room.
It absorbs reflections and echo inside a room but barely stops sound passing through walls. True soundproofing needs mass, sealing, and decoupling.
Styrofoam is the white foam in coolers.
Styrofoam is a trademark for blue XPS insulation board. The white bead foam in coolers and cups is EPS — a different material that performs differently.
Memory foam is the best foam for seat cushions.
On its own it bottoms out under sustained sitting weight and softens with body heat. It works best as a thin comfort layer over a firm HR foam base.
Foam cushions can't go outside.
That's true of traditional indoor polyurethane cushions, which soak up water and stay damp — but not of outdoor cushions. Reticulated dry-fast foam is built for it: water drains straight through the open structure and the cushion air-dries in hours, so mold never gets a foothold.
Technically no. Styrofoam is a trademark for blue extruded polystyrene (XPS) insulation board. The white bead foam in coolers, cups, and packaging is expanded polystyrene (EPS). The mix-up is so universal that even hardware store staff use the words interchangeably, but the two materials perform differently.
It depends on the job and budget. Closed cell delivers roughly double the R-value per inch, blocks moisture vapor, and stiffens the structure, but costs significantly more. Open cell is cheaper, absorbs sound well, and flexes with the building, but needs more depth and separate vapor management in cold climates.
Small two-part DIY kits work fine for rim joists, gaps, and small projects. Whole-house or full-attic jobs belong with professionals: the chemistry must be mixed and applied at the right temperatures, and curing foam off-gasses, so the space needs proper ventilation and protective equipment during application.
Think of them as good, better, best on R-value per inch: EPS around R-4, XPS around R-5, and polyiso at R-6 or higher, with price rising in the same order. XPS handles ground contact and moisture best, while polyiso performs best in warm conditions and loses some efficiency in deep cold.
The fastest way to narrow the field: decide whether the foam needs to cushion a person, protect an object, survive water, or manage sound, then match the cell structure and density to that job. If you are working on a cushion, mattress, or padding project, FoamOrder cuts every foam type we carry to your exact dimensions, and our customer service team has more than 100 years of combined foam experience to help you choose.
Mike leads the family of foam and upholstery brands behind FoamOrder.com and Upholster.com, which have served consumer and commercial customers for over 20 years. A graduate of Duke University and Harvard Business School, he works directly on helping customers get the exact foam and cushions they need.
