Foam Mattress Densities Explained

There are a few terms in the bedding industry as ambiguous as foam density. It is a term marketed widely on the majority of beds. Even Spring coil mattresses consist of high-density foam. However, what does it mean, and what effect does foam density have on a foam mattress?

Foam Mattress Density is a measurement that compares the amount of matter the foam has to its volume, usually expressed in kilogram per cubic meter (kg/m3). In simple terms, if you weigh a 1m x 1m x 1m block of foam, the weight of that block will indicate its density.

The higher the density, the more raw material is used to produce the same size of foam compared to a less dense foam, hence the increased price. A higher density foam mattress means higher quality and durability and should not be confused with firmness. One can have a very high-density rating in foam, and it can be as soft as a very low-density foam.

Another aspect that adds to the confusion of foam density is that some manufacturers add fillers to the foam. These fillers artificially increase the density of the foam without the quality and durability that goes with such an increase. It is therefore essential to note that Sloom uses pure foams without any fillers on our foam mattresses.

Densities of different foam types

There are many kinds of foam, and since they are all produced using different processes and with varying raw material, there are aspects relating to density that you should be aware when comparing different foam mattresses densities.


Polyfoam or Polyurethane foam is by far the most common type of foam, and the least expensive of all the foams to produce. The most common misconception about this type of foam is that it quickly sinks in or sags. Low and medium density polyfoams do sag and indent easily as it can’t support the heavier weights. Higher-density foam mattresses will then be able to support more weight.

Polyfoams with a density more than 23kg/m3 are considered high density. Majority of high-density foams used are in the range between 23kg/m3 to 28kg/m3 depending on whether it is a turn foam mattress or a do not turn foam mattress.

It is important to note that if you are a heavy person, you want to look at high-density foam of more than 28kg/m3 for a core foam. The higher the density, the better it will support you for longer.

The Sloom Original Mattress uses a Pure 35 density foam as the core for better support and durability.

Rebond Foam

Rebond Foam is made from recycled shredded waste foam; usually, polyfoam, reprocessed into one solid foam block and then cut into the desired size. The density of rebond foam is a lot higher than virgin polyfoam but the price per kilogram it far cheaper.

Rebond foam is widely used as a core in foam mattresses and is usually very firm. Densities used can vary between 40kg/m3 to 100kg/m3. Due to it being such a firm foam, it can make the overall foam mattress a bit too firm for someone that isn’t very heavy, even with additional comfort layers. Rebond is not a premium foam.

Sloom don’t use any rebounded foams in our products.

Latex Foam

Latex foam can either refer to natural latex or synthetic latex. The former is made from the rubber tree which doesn’t grow in South Africa, resulting in a hefty price tag for natural latex to be imported.

Synthetic latex, on the other hand, is an excellent premium foam with similar elastic properties as natural latex but with a far better value for the money price tag.

HR Foam

HR Foam or High Resilience foam is technically also a polyurethane foam, but with a few differences due to chemical makeup. It is a premium foam with excellent elasticity, and optimal supporting force, this type of foam distributes pressure across an entire surface as to help absorb motion.

This foam is also very breathable, allowing for a cooler sleeping surface and less heat buildup. To qualify as an HR Foam, the density rating should be at least 40kg/m3 or more.

Sloom uses a 55 Density HR Foam designed and formulated to incorporate properties of latex foam in an all-round durable and breathable foam.

Memory Foam

Memory Foam or Viscoelastic foam mattresses contour to the pressure, returning to its original shape slowly. It has excellent pressure point relieving properties without compromising support. Due to its construction, memory foam is much denser compared to polyfoam, and densities range between 30 kg/m3 to 100kg/m3 for mattress purposes.

Quality memory foam should have at least a 50 Kg/m3 density as anything less is not durable. We use a 55kg/m3 density quality memory foam in our Original mattress.

A Bed in A Box?

Why Compress our Mattresses?

Gone are the days where your only option to buy a bed is to visit a store where the beds are all lined up next to each other begging for a test drive. Consumers can now purchase their beds online and have it shipped to their doorstep compressed inside a box. Hence, bed in a box

Innovative packaging technology allows mattress manufacturers to reduce the packaging size of a mattress drastically. A Sloom mattress’s volume is reduced by around 70% of its original volume. This allows us to ship the bed in a box across South Africa cost-effectively.

The bed in a box concept, however, isn’t new, as the industry booms overseas with brands like Casper and dozens of other dot-com start-ups that have arrived on the scene over the past four years. The model of distribution in the bedding industry has seen significant disruption so much so that conventional mattress brands are also gearing themselves similarly to compete.

In South Africa, the adoption of these technologies has not been that significant, with a few start-ups coming and going. Mainly because cheap mattresses make the bulk of the South African market, and cheap mattresses can’t be compressed because they will not recover. As we see more and more customers getting used to shopping online, we can expect the online retail industry for beds to pick up as well with the bed in a box concept that’s perfect for eCommerce.

How Does Mattress Compression Work?

The mattress is placed on the conveyer belt of an industrial machine and then encased in a thick plastic bag before being compressed by a heavy press and sealed. The machine presses all present air out of a mattress before folding. The mattress now looks more like a duvet than a mattress with all the air pressed out.

It continues down the conveyer belt where it’s then rolled up tightly and placed into the tightly packed cylinder which the consumer takes out of the box.

Does Compression Damage The Mattress of the Bed in a Box?

The integrity of the mattress and its cover is perfectly preserved and will recover fully when taken out of its compressed state. It’s important to note that only high-quality foams can be compressed in this fashion. Many manufacturers use low-density foams or foams with fillers in their mattress construction. These types of foams will not recover to their original state after being compressed. A different kind of foam that can’t be compressed is reconstructed foam or rebonded foam. This type of foam is used widely as a core for mattresses even on some high-end mattresses.

Sloom uses only High-Density Pure Foam with no fillers to artificially increase the density in our mattresses. This guarantees that the product will arrive at your door in the condition it has been designed for.

Another essential aspect to note is how long the mattress has been in a compressed state for. Even with the best foams on the market, the mattress can’t stay in a compressed state forever. After about two months the foams do lose some of its firmness. Therefore, it’s imperative to instead buy from a local brand. With imported brands, there is no way to tell how long that mattress has been in that state.

What About the Base of a Bed in a Box?

Seeing that a mattress is not complete without its base, the challenge comes in to reduce the shipping volume of the base for economical eCommerce. Since the base cannot be compressed like the mattress, it takes a design approach to the base itself to overcome that challenge.

A flat-pack base that you assemble at home reduces the shipping size significantly while offering a modern look to your bedroom. These types of bases are prevalent overseas with stores like IKEA popularising it even further.

In South Africa, there isn’t any local manufacturer, except Sloom, that manufactures these types of bases; mainly because it’s so much cheaper to make a standard base. All the flat pack bases that are available in retail stores are imported and usually not very sturdy. We spend many hours developing a flat-pack base that looks good and can support the same weight as the mattress.


In the past three years of designing and creating Sloom’s products, there were many opportunities just to import all these products. Local manufacturers were reluctant to create something new and many manufacturers implementing ridiculous minimum orders made it very difficult to get the product to what it is now.

But thankfully, today, we can offer a proudly South African brand that is on par with global innovation and technology.

What Makes for the Best Memory Foam Mattress?

You don’t have to be in the bedding industry to have heard of memory foam, either positive or negative. The market has become entirely swamped with every other bed now consisting of memory foam in some form or the other. But hopefully, with this article, we can guide you to make an informed decision in searching for the best memory foam mattress.

What is Memory Foam?

Memory foam or Viscoelastic foam is a type of polyurethane foam with pressure-sensitive body moulding properties. It can be identified by its slow rebound after pressure has been applied. It was developed under a contract from NASA for the US space program back in the 1960s.

The best memory foam

Many people with negative opinions about memory foam are those who compare it to a memory foam bath mat. That, or a cheap memory foam pillow from China. But it is essential to understand that there are different types of memory foams out there, and some of them lack the quality associated with memory foam.

Memory foams are generally high in density. To save on cost some manufacturers produce a lower density memory foam and market it under the same name. These type of memory foams are less durable and offer less support than high-density memory foam. In our Sloom mattresses, we use a 55 kg/m3 memory foam, providing the most comfort, durability and pressure relief memory foam has to offer.

Sleeping hot

Due to memory foam’s high density, restricted airflow causes heat to build up inside the foam, causing it to heat up. This is one of the most significant disadvantages of memory foam. Development of memory foam through the years has improved the “openness” of the foam somewhat but still trails behind other foams.

With the Sloom mattress, the design allows for better airflow due to the combination of very breathable foams with memory foams. This design will enable us to take the advantages of memory foam with less heat accumulation.

Strong odours

Some memory foam mattresses have a strong scent after taking it out of its packaging. Not to worry, this off-gassing will dissipate with time, usually within a day or two. These gases are not harmful in memory foam beds, just irritating. We make extra sure that our mattresses cure appropriately before packaging it, reducing any chemical smells.

Other benefits of a memory foam mattress

Not only is memory foam excellent for pressure point relief and spine support, but motion transfer is drastically reduced, resulting in a disturbance-free sleep.

Generally, the lifespan of a memory foam mattress is significantly longer than other types of mattresses, but this can also be influenced by a few factors like the quality and density. The Sloom Mattresses only use premium memory foam, so you know you’ll have a product that lasts.

In conclusion, memory foam is one of the best foams if not the best foam on the market with its pros far outweighing its cons. With innovative design and premium quality materials, these negative aspects can be drastically reduced if not avoided altogether.

The Best Mattress in South Africa

Most of us start our process of buying a new bed by searching the internet for the best bed or memory foam mattress in South Africa. Usually, it's just a mess of web pages filled with confusing information.

Here is a quick guide on how to choose the best mattress in South Africa.

Value for money

The first thing is to decide on your budget. Unfortunately, most of us still live in the past when it comes to budget expectations. The same old budget of R1000 gives one a very slim chance of getting a decent bed, let alone the best in the country.

Everyone's financial situation is unique, but a better perception of the value of a bed in one's life could help one make a decision effectively. Considering the importance of sleep, investing in a good memory foam mattress goes without saying.

Many of us spend more money on our cell phones than on a good quality bed, the latter having a direct influence on the quality of our lifestyles and our health.

Expert Tip: Bed shops, in general, tend to add quite a significant markup from the factory, understandably so, due to overheads, but buying directly from Sloom allows you to get far better value for your money. 

Comfort preference

Different sleeping styles require different types of firmness levels. Side sleepers typically prefer a softer sleeping surface as this accommodates the natural curve of the spine and maintains proper alignment throughout the night. A firm mattress, on the other hand, will support a stomach sleeper better.

Expert Tip: It's almost impossible to determine whether the comfort preference is perfect for you by just laying on it for a few minutes in a store. Therefore, the Sloom memory foam mattress is superior to any other memory foam mattress on the market; you can zip open the cover and adjust the sleeping surface firmness at any time. And since you and your partner have different sleeping styles and preferences, you can split the comfort left and right. 

Weight limit

The weight limit is usually an excellent indicator of the quality of the memory foam mattress. The more weight it can hold, the better, even if you don't come close to exceeding the limit. Better quality materials (in most cases) equal a higher weight limit. The minimum to consider is a 100kg per person weight limit.

Expert Tip: The Sloom Mattress makes use of premium luxury foams that can support up to 150kg. Much more than your average bed. 

Warranty and Guarantee

Another good indication of the quality of the bed is the service warranty the manufacturer is prepared to give the mattress. Each manufacturer has a warranty policy so that I won't go too much into that, but for this purpose, it's an effective way to compare different beds and brands. Usually, entry-level mattresses start with a 5-year service warranty, if any, and go up from there. Your top of the range beds typically come with a 20-to-25-year service warranty. If you want more info on what the difference is between a warranty and a guarantee, follow this link.

Expert Tip: Buying directly from Sloom ensures sufficient claim resolution in the event of a defective product, reducing the red tape usually found in such situations. 

Type of Memory Foam Mattress

Every bed on the market consists of foam in the design, even an innerspring mattress. Rule of thumb is the higher the density of the foam, the better the quality. But these technical specifications are not always available to the consumer, especially in South Africa, making it very hard to compare beds. But to simplify things, the highest density foam types usually found in mattresses are memory foam, natural and synthetical latex foam and high resilience foam.

Expert Tip: In the Sloom mattress, we make use of 3 different types of these luxury high-density foams, each with their unique properties. 

Spinal Care

In our first blog post, we discuss how the term orthopaedic is just a marketing term used with little to substantiate it. Instead look at a good quality bed, which supports your spine correctly with premium quality materials.

Expert Tip: Comfort was the focus when designing the Sloom mattress, but rest assured that with the premium materials we used your spine and body will thank you for all the support.

Motion Transfer

If your partner's midnight movements disturb your sleep, then a bed with minimal motion transfer should be a priority. Beds that reduce motion are pocket spring mattresses and mattresses with foam with a high absorption rate like memory foam.

Expert Tip: We have taken disturbance-free features on step further with split comfort layers on the left and right that move independently from each other. Meaning no motion is transferred to your partner. 



Is the term "Orthopaedic Mattress" a marketing ploy or real?

Buying a new bed in 2019 can be a tricky decision, with every brand offering the supposed "best" product on the market. 

In this article, we will be looking at the latest in local marketing trends: The orthopaedic mattress.

"Orthopaedic Mattress?"

A few weeks ago, I had a terrible sleeping experience at a guest house I visited. The mattress supplied was extremely firm with minimal comfort layers to reduce pressure points.

As a result, I woke up every hour with pain in my hips and side. I have since come to realise how loosely the South African (and frankly, the international market for that matter) mattress industry uses the term.

Bed manufacturers are not required by law to provide proof that they can produce a real orthopaedic mattress.

So what is an orthopaedic mattress? 

Simply put, it's a mattress designed to support your back and joints or combat problems that arise from a bad back or joints. And by that definition, to some degree, even the cheapest of mattresses can be called Orthopaedic. To be fair, it does sleep better than the floor and offers better support than a hammock, but is it ethical? Someone is buying that mattress with the impression that the mattress will improve their sleep and support their spine. Bed shops are under no obligation to refund your purchase on the premise that their product isn't Orthopaedic.

So how would one know what bed to choose if you suffer from back or joint-related pain? 

There are plenty of useful guides on the internet on choosing the right bed, but the main thing is not to be fooled by the term Orthopaedic. Instead, leave that out of the equation entirely and research which materials are in the mattress. 

High-quality materials will support your spine and relieve pressure points. A good indication of this is usually the guarantee and service warranty a manufacturer is willing to put on the product. Avoid opting for anything less than 15 years service warranty. 

Another indication of a good quality mattress is the weight restriction that the manufacturer places on it. Usually, the higher the weight limit, the better the quality material used. Even though your weight might not come close to that limit, it is always better to go for a mattress that can support more than 120 kg per person.

In conclusion, it is safe to say that although some companies are legitimately selling products aimed at bettering your quality of life, many are interested in your money before your comfort levels and sleep.