To help you understand mattress foam

Mattress specifications

Understanding foam grades

Foam specifications are shrouded in secrecy in the Australian mattress industry. Quite often, the salesperson won’t even know the foam grades used in a mattress because the manufacturer hasn’t revealed the full specs to them.

At Sherman, we believe in full disclosure. We reveal our full specifications to you including the layers of foam and the density ratings of each. We do this because we are extremely confident of the quality and the value in our mattresses. I would be very suspicious of any mattress store or salesperson that won’t give you all of these facts.

Understanding these foam grades is not difficult. Here’s a quick run down on the things you need to know:

Foam is made up of open cells like bubbles, inside each bubble is air. Foam, like a lot of things in life, is sold by weight (or density, technically). The quality and price of foam in Australia is measured by the density rating. This rating will also tell you vaguely how many cells the foam has, how thick the walls of each cell are and how much of the foam is made up of air. The more cells; the better. The thicker the walls of each cell; the better. The less air; the better. So, the more dense the foam; generally, the better.

All comfort layers in mattresses are made up of foams. Latex is a foam, as is Visco elastic or Memory foam. Manufacturers make up fancy name for their foams to try to confuse you or trick you into thinking that their foam is superior. Ignore names like “Envirofoam”, “Cloudcell” and “Endura”. These names have no bearing on the quality of the foam or how long it will stay comfortable. Other claims such as a foam being “exclusive” to the product, also don’t really mean that the foam will bring you any extra benefit.

With foam, it’s all about the density rating.

In Australia we use foam grades that look like this example: 19/130. The first part (19) is the density rating. This basically means that a one-cubic-meter block of this foam will weigh 19 kilograms.

The second part of the rating (130) is an indication of how soft the foam feels. We’re going to leave this part of the rating out of our discussion since it’s highly subjective. The softness doesn’t affect the quality, longevity or price of the foam and you will generally know whether you like the softness of the mattress when you lie on it. This “softness” number is also not tied to the density rating at all. You can have 19kg foam that feels very soft and you can have 19kg foam that feels very firm.

Bedding foam density ratings will generally be anything between 10kg and 50kg.

Dense foam will last longer and retain its buoyancy and elasticity longer. This means that the foam will stay comfortable for longer. At the other end of the scale, low density foam (like 10kg foam) will break down and lose its comfort very quickly. You wouldn’t expect a mattress made with 10kg foam to stay comfortable for more than a few months.

When looking at foam grades, you also need to look at how thick each layer of foam is in the comfort layers. The oldest trick in the book is to list a layer of expensive, dense foam in the specifications but fail to mention how much of it there is. A layer of any foam that is less than 10mm thick is pretty much useless but manufacturers will include this just so that they can make the mattress more expensive.

Just as important is to not have too many layers of foam. A manufacturer can save money, and also “plump-up” the look of the mattress by using many thin layers of foam instead of just two or three. Beware of any mattress specifications that list more than 5 layers of foam.

In a perfect world, all mattress manufacturers and retailers would be happy to reveal how many layers of foam are in the mattress and the density rating and thickness of each layer of foam in the mattress. You would then be able to take these specifications to each mattress store and compare the value of other mattresses.

In the real world, however, you’ll find that manufacturers and retailers will go to great lengths to hide these specifications from you. Don’t believe me? Try going into a big-brand mattress store and asking for the foam specifications in a mattress. Ask the salesperson to list the exact thickness and density rating of each layer of foam in the mattress. Even better, ask to see where the specifications are published (so that the salesperson can’t just rattle off some fictional numbers).


Understanding MEMORY FOAM (Visco elastic foam)

Viscoelastic polyurethane foam, more commonly known as memory foam, is a premium foam used in high-quality mattresses. It’s unique, therapeutic qualities of relieving pressure and alleviating fatigue and soreness combined with it’s amazing durability make it one of the most desirable foams that you could want in a mattress.

In 1966, NASA wanted to improve the probability that someone in it’s spacecraft seats would survive a crash. Engineers developed an open-cell, polymeric “memory” foam material that possessed unusually high energy absorption, giving a minimum reaction time through its molecule mobility.  Initially referred to as “slow spring back foam,” this open-cell structure offered extreme decompression qualities while still maintaining softness and pliability.

Now more commonly known as memory foam, it is simply a polyurethane foam with the addition of chemicals that increase its viscosity and density. Since it’s development, it has been re-engineered several times and is now used extensively not just in beds but as cushioning in helmets and shoes and for medical applications such as prosthetics. One of the most established uses in medicine is in beds and seating pads to prevent pressure ulcers with patients who are immobile.

The new second and third generation memory foams have more of an open-cell structure that ‘moulds’ to the sleeper’s body in an even more superior way, helping to distribute body weight more evenly and providing incredible comfort. Furthermore, the new open-cell structure of the foam allows it to breathe, preventing heat build-up.

The type of materials used and the dense structure of memory foam discourages dust mites more effectively than normal polyurethane foam and is largely hypoallergenic (good for those with certain allergies).

Most memory foam has the same basic chemical composition; however the density and layer thickness of the foam makes different mattresses feel very different. As with all mattress foams, a high-density mattress will have better compression ratings over the life of the bedding. A lower-density one will have slightly shorter life due to the compression that takes place after repeated use.

Recommended by health and sleep experts alike, a mattress that utilises memory foam alleviates pressure and paves the way for healthier blood circulation. The use of the foam will also minimise tossing and turning in bed, reduce back, shoulder and neck pains and increases the quality of your sleep.


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Understanding LATEX FOAM

Natural Latex is a milky substance (also known as natural rubber) from the Para rubber tree. It is not the tree sap but rather a secretion from within the central part of the tree. This secretion is harvested and turned into a foam, among many other uses such as medical gloves, contraception and high-quality paint. The largest producers of latex are in Malaysia, Sri Lanka and Indonesia. It is not produced commercially in Australia.

As a bedding foam, natural latex is considered to be a premium material because it is expensive to produce and offers superior durability compared to polyurethane foam. Solid latex mattresses have been known to last for more than 20 years. However, durability does not equal comfort! Natural latex has a consistent and unavoidable firmess, which can be good when used as a layer in the comfort layers of an innerspring mattress but not suited to everyone as a solid core mattress. Whilst it has similar pressure-relieving properties to memory foam, it has a totally different feel, being a much firmer and more resistant feel to memory foam.

Since latex is considered to be a premium component, manufacturers may include it in their specifications in order to increase the mattress price without necessarily increasing the benefits to you. When a thin layer of latex is added to the comfort layers, such as a 10 or 12mm layer, then you will not gain any real benefit as this is too thin to increase the comfort or longevity in a noticeable way. Likewise if the latex layer is placed at the bottom of the comfort layers, closer to the springs (being a firm foam, manufacturers consistently do this) then the addition of the latex offers no real benefit.

One of the major problems with buying mattresses in Australia that contain latex, is that we have no regulations as to what types of foams can be labelled as Latex – meaning that a 100% synthetic equivalent can still be marketed as Latex.

Another issue with buying latex is that manufacturers or retailers can label the latex as “natural” when the product may only only contain a fraction of natural product with the remainder being synthetic. Once again, there are no regulations governing the use of the word “natural” when it comes to marketing latex. It is worth noting that natural latex needs a certain amount of chemicals added in order to create a foam from the core ingredient. Even the most “natural” of latex foam is at best, only 96% natural. You should be highly suspicious of anyone who claims that their latex is 100% natural, as you should of anyone who claims their product to be 100% organic or a “healthier” choice to other bedding foams.

Synthetic latex, formed with the use of a chemical called Styrene-Butadiene, is not as resilient or durable as natural latex. It also can’t match the breathability of it’s natural cousin and has earned a bad rap in Australia for being very hot to sleep on. One of the easiest ways to spot synthetic latex as a buyer is a low price. On international commodities markets, the natural product sells at a high price. A mattress advertised as being latex, with a price point lower than several thousands of dollars would most likely not be a solid core mattress of the natural product.

As you can see, there is plenty to be wary of when buying a latex mattress. Whilst we at Sherman know that natural latex is a superior foam to use in bedding, we choose not to use latex in any of our mattresses. Recent health reports state that up to 15% of the Australian population are allergic to natural latex. So it is this, coupled with the lack of labelling regulations that lead us to not manufacture with this product.

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