Mattress

A mattress is a piece of bedding typically consisting of multiple layers of foams and fibers, along with an innerspring unit used to provide support to one's back during sleep. Mattresses are usually used along with a foundation, which might include metal springs or torsion bars on a wooden frame, which supports the mattress. Increasingly, mattresses made with various foam materials such as latex foam, visco-elastic foam and other polyurethane type foam but without metal spring units are becoming common and accepted. Although there are mattresses made of air, water foam and futons, innerspring or coil mattresses currently have over 80% of the market share in the U.S.

The fabric used to cover the exterior of a mattress is called mattress ticking. With modern production methods, it takes 10 to 60 minutes to make a mattress from start to finish.

History

Ancient times: Prehistoric humans, simply huddled in groups for warmth at night and slept on the ground or directly on floor boards (in many Asian countries today people still sleep directly on the floor with a simple thin grass mat under them).
10,000 to 8,000 years ago (Neolithic period): The quest for comfort brought on the invention of the mattress and then the bed. An important change was raising them off the ground, to avoid drafts, dirt, and pests. Humans began sleeping off the ground, on primitive beds or mattresses. Most probably, the first "mattress" was a pile of leaves or grass with animal skins thrown over it. With time, humans probably also used straw to sleep on. Then, people started putting the "soft" materials on some kind of cloth (which eventually evolved to be called mattress ticking). The bags or sacks were initially filled with grass, straw, pea shucks, rags, etc.
3600 BCE: The first water-filled beds were goatskins filled with water, used in Persia.
3400 BCE: Egyptian people slept on palm bows heaped in the corner of their home.
200 BCE: Mattresses in the Roman Empire were bags of cloth stuffed with reeds, hay or wool. Wealthy people filled the bags with feathers. Romans discovered the waterbed. The sleeper would recline in a cradle of warm water until drowsy, then be lifted onto an adjacent cradle with a mattress, where they would be rocked to sleep.
15th century: In the Renaissance, mattresses were made of pea shucks or straw, sometimes feathers, stuffed into coarse ticks, then covered with sumptuous velvets, brocades and silks.
16th and 17th centuries: Mattresses were generally stuffed with straw or down, placed atop a latticework of rope. A typical bed of 1600 in its simplest form was a timber frame with rope or leather supports. The expression "sleep tight" comes from the 16th and 17th centuries when mattresses were placed on top of ropes that needed regular tightening.

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Photo on a 1940 USDA circular promoting home production of cotton mattresses

18th century: Mattresses were stuffed with cotton or wool.
Mid 18th century: Mattress covers started to be made of quality linen or cotton. The mattress cane box was shaped or bordered and the fillings available were natural and plenty, including coconut fibre, cotton, wool and horse hair. The mattresses also became tufted or buttoned to hold the fillings and cover together and the edges were stitched.
1857: The steel coil spring was invented and first patented for use in a chair seat.
1865: The first coil spring construction for bedding was patented. Mattresses were lumpy up to the late 1800s, when the box spring was invented. Even the box spring mattresses were lumpy, but at least the springs made it more comfortable.
1871: The German Heinrich Westphal is credited for inventing the innerspring mattress. He lived in Germany and died in poverty, having never profited from his invention.
1873: Sir James Paget at St. Bartholomew's Hospital presented a waterbed designed by Neil Arnott as a treatment and prevention of pressure ulcers (bed sores). Waterbeds allowed mattress pressure to be evenly distributed over the body.
1895: A few waterbeds were sold via mail order by the British store Harrod’s. They looked like large hot water bottles.
1930's: Innerspring mattresses and upholstered foundations slowly became the most widely used form of mattresses. Artificial fillers became common. The most expensive beds of 1929 were latex rubber mattresses produced by Dunlopillow. Pocket spring mattresses were also introduced. These were individual springs sewn into linked fabric bags.
1940's: Futons were introduced to North America.
1950's: Foam rubber mattresses and pillows appeared on the market.
1960's. Modern waterbed was introduced. Due to lack of suitable materials, the waterbed did not gain widespread use until this decade, when vinyl was invented. Also, adjustable beds become popular with consumers.
1980's. Airbeds were introduced. The mattress was an inflatable unit made with vynil.
1987: Select Comfort introduced their "Sleep Number" bed, which featured an inner core of air which could be inflated and deflated on demand, to provide for variable levels of firmness.
1992: Tempur-Pedic introduced their pressure-relieving "Swedish Sleep Systems" mattresses using TEMPUR branded visco-elastic memory-foam. Memory-foam was originally invented for NASA to relieve the pressure of the tremendous G-forces exerted on pilots during liftoff and flight. During the following 10 years, the company had average yearly sales increases of 49%.
1999: For the first time ever, the queen-size mattress beat the twin-size to become the US most popular choice for mattress size.
Currently: Most mattresses use springs(coils) or solid foam.

Mattress dimensions

Most mattresses have a thickness from 6" to 14".

International Mattress Sizes
Denomination	USA & Canada	Europe (UK)	Asia (Thailand)
Twin/Single	39" × 75"	36" × 75"	42" × 78" × 22"
Double/Full	54" × 75"	54" ×75"	48" × 78" × 22"
Queen	60" × 80"
Olympic Queen	66" x 80"
California Queen	60" x 84"
King	78" × 80"	60" × 78"	72" × 78" × 22"
California King	72" x 84"
Super King		72" × 78"

When does a mattress need replacing

After 7 to 15 years of use, although many people use their mattresses for many more years.
Experts indicate that two adults sleeping nightly on a queen mattress will notice the padding, not the coils, breaking down after a period of 4 to 6 years. While the mattress will still be comfortable, it will no longer feel the way it did when first purchased.
When the mattress has lumps.
When the user regularly wakes up feeling tired, stiff, achy and sore.
When inner coils start springing out of the mattress.
When the mattress shows very visible deformities.
When the mattress looks old, frayed or worn.
When the mattress is normally sagged, has lost its flat shape and there is an impression of the user sleeping on it.
When the box spring creaks and squeaks.
When the user has difficulty finding a comfortable position to sleep in.
A thing to consider is that a regular person exudes about 0.5 liters of liquid a night, altough probably the majority of it evaporates. Mattresses normally absorb moisture from the body, so after years of use it is probably saturated with the salts of the perspiration.

Components of an innerspring mattress

A common innerspring mattress consists of 3 components:

The spring mattress core, also called innerspring unit.
The foundation, which many people call box spring (but it is not always a box spring)
Upholstery layers, which encase the mattress core.

Spring mattress core

The core of the mattress is the most important part in the support of the body. In most modern mattresses (except for the foam-only ones), it is made up of steel coils springs, also known simply as coils. The steel coil spring was invented during the industrial revolution and was first patented for use in a chair seat in 1857. Then, in 1871, Heinrich Westphal invented the innerspring mattress. He lived in Germany and died in poverty, having never profited from his invention.

Number of coils

Basically, the more coils a mattress has, the more support it will give the user. As a general rule, very firm mattresses have a high coil count. Generally, but depending on the mattress size, they come with 300 to 800 coils. Depending on the size, 500 to 800 coils is considered firm. However, some expensive and comfortable mattress only have around 400 coils. and it takes as few as 312 coils in a full mattress to provide decent support. Assuming that the overall coil count is decent, a heavy duty innerspring mattress may also increase the longevity of the mattress for large users.

Gauge of the coils

Obiously, heavy gauge (thick) coils will offer a great deal of support while light gauge coils will give less support. A low coil count and heavy gauge wire can pass as a firm mattress on the store, but it is likely that this mattress will become lumpy quickly because it does not have enough coils. Many premium mattresses feature 14-gauge coils. Coils are measured in quarter increments. The lower the number, the thicker the spring. With coils of 14 to 15.5 gauge, it is important that the total coil count be high to compensate for the fact that they give so easily under pressure. A 12.5 gauge innerspring, the thickest typically available, may feel rock hard in a double mattress even with a coil count of 400 or less.

Connections between the coils

Generally, the number and quality of these interconnecting wires is not published by the manufacturers. If there are too few of these interconnecting wires a mattress can lose its shape more quickly than one that has an adequate amount. Mattresses that sag quickly usually have few interconnecting wires. There are some manufacturers that make individually pocketed coils, which avoid movement on different sides of the bet because they are not interconnected. However, the special pockets provide the support required by the coil instead of the interconnection with other coils.

Types of coils

Construction-wise, most manufacturers claim to have the best coil-to-gauge ratio. However, there are only a few innerspring manufacturers and 4 general types:

Bonnel coils

These are the oldest ones and most commonly used. They were adapted from buggy seat springs of the 19th century. They are still prevalent in low priced mattresses. They have an hour-glass shape, and the ends of the wire are knotted or wrapped around the top and bottom circular portion of the coil(round-topped and self tied).

Marshal coils

Also called pocketed coils, they are individually pocketed and less frequently used. Might not be properly tempered.

Offset coils

Bonnell coils evolved into Offset coils, which are currently popular, but happen to be the most expensive ones. They are almost identical to the Bonnell coils, except that the top and bottom circular part of the coils have flat or straight sides, which allow for better hinging action when they are placed together in a spring unit, and which can be easily aligned. Brands as Stearns and Foster use regular Bonnell coils in their mattresses. An evolution of the offset coils brought the elimination of the knot that tied the end of the wire to the coil. In other words, offset coils might be tied off or feature a loose end (sensory arm). These are called "open end offset coils". These improvement gave offset coils an extra turn of working wire for greater spring action on each end of the coil. However, loose ends increase the odds that a spring will begin to punch through the padding. Brands like Sealy and Spring Air use open end offset coils in their mattresses.

Continuous coil

They look like double wire spirals or loose ringlets, creating a network of wire that runs nonstop through the entire bed.

Foundations

Although in the past the foundation actually contained springs, increasingly today this foundation functions primarily to elevate the mattress, serving no ergonomic function. There are 3 main types of foundations:

Traditional wood foundation

It is usually made of of pine or similar hard wood. It usually has 7 or 8 support slats, covered with cardboard or biverboard. This type of foundation, called by the industry a zero deflection unit, increases the feeling of firmness or stability.

Box spring

It features extra-heavy-duty springs. If the springs match the mattress it is called a coil upon coil box spring. Since a box spring has coils, it generally increases the give in the mattress, which in turn produces a softer or bouncier feel.

Grid foundation

It is a combination of steel and wood.

Upholstery layers

The mattress core is covered by several soft materials, which provide cushioning and comfort. They are divided into three types:

Insulator
Middle upholstery
Quilt (which includes the cover called ticking).

Aside from the number and gauge of the coils, the upholstery layers are used to differentiate the different "qualities" of mattresses that manufacturers produce.

Choosing a Mattress

There is no proven scientific way of finding the right mattress, so the best advice is to try it out.

Testing a mattress

The prospective buyer should lie on it at for least 10 minutes, trying different positions.
Lying on the back: If a user slides his/her hand under the small of the back, and it is very easy and his/her shoulders and hips are uncomfortable, the mattress is too hard. If there is no space between the user's back and the bed, it's too soft.
Rolling over: If it takes a lot of effort, then the bed is too soft. If it uncomfortable for the user's hips and shoulders it is too hard.
The user should test the mattress on the type of base that it will be used on.
If the bed is for two people, both users should try it at the same time.

What to look for

The mattress should be designed to conform to the spine's natural curves and to keep the spine in alignment when laying down.
It should have perimeter edge support. Usually, this will be a heavy gauge border rod, however, in some high end models, a high density foam encased spring unit will provide firmer edge to edge comfort and support.
It should be designed to distribute pressure evenly across the body to help circulation, decrease body movement and enhance sleep quality.
It should be designed to minimize the transfer of movement from one sleeping partner to the other. The marshall coil and visco-elastic memory foam designs achieve this better than traditional coil systems.
On a same size mattress, more coils of a lower gauge(thiner) may give better support and last longer than fewer coils with a higher gauge(thicker). A good warranty, 15 years being the best, will ensure your lower count-higher gauge coil mattress is of lasting quality.
While Serta, Sealy and Simmons are the three largest manufacturers in the United States, largely due to advertising, brands such as Englander offer the same quality, usually at much lower prices due to not advertising.

Firmer or softer

There are 3 main sleep positions: Back, stomach and side. During a night's sleep, most people use more than one position. The sleeping position determines which part of the body will interface with the mattress, which in turn determines the amount of stress to the body.

Firm preference

Orthopedic doctors usually recommend a firm mattress because it will not allow back or stomach sleepers to sag into the surface at unnatural angles. Air, water or foam mattresses are not generally recommended because they do not provide this level of support.
Stomach sleepers probably need a firmer mattress to prevent spinal distortion that can result in back pain when waking up.
It is easier to soften up a firm mattress with the proper padding or bedding, than it is to firm up an overly soft one that is causing a backache.

Soft preference

Side sleepers usually face the greatest amount of weight on the smallest areas of the body thereby creating pressure points, which reduce circulation and can be a cause of the tossing and turning during sleep. A side sleeper will probably want a softer mattress, to minimize pressure points, especially if they have a very curved or rounded figure.
A study of sleep quality and bed firmness showed that 4 of 9 male subjects slept significantly better on softer mattresses and 2 on the harder mattresses.

Nor firm nor soft

Back sleepers need a mattress that offers enough support to fill in the gaps in the contour of the back, while at the same time providing enough comfort, according to the user's preference.

Fluff & sag

Fabric is the most expensive element of mattress construction. Wool, silk, foam and cotton all increase the cost of the mattress. Thick layers of padding are more likely than the springs to compress to the point of feeling like the mattress is sagging. The faabric, foam or cotton eventually become concave because thick plush or pillowtop components eventually break down even if the springs do not. Unlike an eggcrate or other forms of padding, the mattress inner components cannot be removed and replaced when damaged.

Size

Twin & Double are 75 inches long; Queen & King are 80 inches long; California Queen & California King are 84 inches long. According to experts, a mattress should be at least 6 inches longer than the tallest person who will be sleeping on it. Be aware that the bigger the mattress, the more expensive the sheets.

Maintentance and care

A new mattress should be put on a firm base. Never on a saggy base.
Most manufacturers of box spring mattresses suggest that the consumer should regularly rotate and flip the mattress and box spring. Otherwise, even the most expensive mattress will fail. Most manufacturers recommend to rotate the mattress (180 degrees, so the head of the bed becomes the foot) every 3 months and to turn the mattress at least twice a year. Some manufacturers recommend to alternately turn and flip the mattress once every two weeks for the first three months and then twice per year after that. The foundation should also be turned every 12 months. All mattresses need to be rotated to reduce wear patterns that develop over time.
Do not wet a mattress. An impermeable mattress protector can be used to keep it clean.
Use a vacuum cleaner for regular cleaning. Vacuuming is the only recommended way to clean a mattress.
Use a good quality washable mattress pad to keep the mattress free from stains. If stained, use mild soap with cold water and rub lightly. Do not soak a mattress or foundation.
The mattress should not be lifted or carried using the handles, which are only for positioning it.
The mattress should not be folded or bent.
It is not good to habitually sit on the same spot of the mattress edge.

Glossary

Air Bed
Bed Frame or Bed Base/Frame
Bed Rails
Body Impressions
Bonnell Coil
Border Rod
Box Spring
Bunkie
Bunkie Board
California King
Cambrick
Center Rail
Channel Quilt
Clipped Border Rod
Coil Count: Number of coils in the mattress or box spring.
Coils
Comfort Layers
Cone-Shaped Coil
Continuous Coil
Continuous Quilt
Cover
Crown: Convex surface that is higher in the middle than in the sides, used in some mattresses.
Cushioning
Damask Cover
Density
Double Bed
Double Extra Long
Fatigue
Felt
Fiber
Filler
Firmness
Flanging
Flipping/Rotating
Foam: Padding material used in mattresses, including: Latex, Polyurethane and Visco-elastic or Memory Foam.
Foundation
Full Extra Long
Garnetting
Gauge
Grid
Helical Wire
Hinged King
Hog Ring
ILD: Initial Load Deflection. A measure for the firmness level of foam.
Inner Quilt
Inner Tufting
Innerspring Unit
Insulator
King
Knit
Lacing Wire
Latex
Mattress
Mattress Handles
Migration
Multi-Needle Quilt
Offset Coil
Platform Foundation
Pillow Top
Pocketing
Posturized
Pressure Points
Queen
Quilting
Resiliency: Ability of the spring, foam, fabric or fiber to spring back to its original form.
Ride: Reserve "springiness" and ease of vertical movement that a mattress has when a user is lying on it. When sleeping, the user's body moves subtly with every breath. A "bottomed out" mattress doe not easily move with the sleeper, causing aches after some time.
Roll-Together: When a defective or worn out mattress sags in the center and causes the body of the sleeper to want to roll towards the center of the mattress.
Rotating: Turning a mattress 180 degrees so that the head of the bed becomes the foot.
Sagging
Slats
Smooth Top
Split Queen Box
Spring Wire
Support
Tack and Jump
Tape Edge
Tempering/Stress Relief
Thermally-Bonded Cotton
Topper Pad
Twin
Twin Extra Long
Tufting
Upholstery Layers: These includes all the soft layers of a mattress, such as insulators, covers and quilts.
Ventilator
Viscoelastic foam

Trivia

In Life, the Universe and Everything by Douglas Adams, mattresses are "...large, friendly, pocket-sprung creatures which live quiet private lives in the marshes of Squornshellous Zeta. Many of them get caught, slaughtered, dried out, shipped out, and slept on. None of them seem to mind and all of them are called Zem." Very few mattresses actually come back to life and attack the sleeper.