Last updated: June 2026
A sponge mattress is simply a foam mattress made from solid foam right through, with no springs inside. In South Africa "sponge" is just the everyday word people use for foam - the same way we say "bakkie" instead of pickup. A good sponge mattress is made from high-density, high-resilience foam that gives firm, even support and holds its shape for years. A cheap one is made from low-density foam that feels fine for a month and then collapses. The difference between the two is density - and that is the one thing you need to understand before you buy.
So let me explain it properly, because "sponge bed" gets a bad reputation it does not always deserve.
Why people call it a "sponge" mattress
It is a South African thing. Walk into a shop anywhere on the platteland and ask for a sponge mattress, and everyone knows exactly what you mean - a foam bed. No coils, no springs, just foam. The word is honest. It is foam. The question is never "sponge or not" - it is "good foam or bad foam".
The thing that actually matters: density
Here is the part the cheap sellers skip. Two sponge mattresses can look identical and one will last ten years while the other dies in eight months. The difference is density - how much actual foam is packed into the same space.
- High-density foam is heavy, firm and resilient. It springs back. It supports your spine. It carries weight without sagging. It lasts.
- Low-density foam is light and airy. It feels soft and nice in the shop. Then it compresses where you sleep, develops a dip, and stops supporting you.
When you buy a sponge mattress, density is the spec to ask about. If the seller cannot or will not tell you, walk away - it is low. Our Comfort sponge bed mattress is built from high-resilience foam exactly so it holds its shape and supports your back year after year, not month after month.
Is a sponge mattress good for your back?
A good one, yes. High-resilience sponge foam keeps your spine aligned and supports you evenly - which is the whole job of a mattress. Firm enough to support, comfortable enough to sleep on every night. That is what prevents the morning stiffness people put up with for years.
A bad one, no. Once low-density foam sags, your spine bends through the night and the bed becomes part of the problem. This is exactly why density matters more than the label. There is more on this in our guide to the best mattress for back pain.
Who is a sponge mattress right for?
This is where the Comfort earns its place. A quality sponge bed is the smart-money choice for:
- Kids' rooms - durable, supportive, and you are not overspending on a bed they will outgrow.
- Spare and guest rooms - real comfort for visitors without a showroom price.
- Domestic quarters and staff rooms - proper support at a fair price.
- Guesthouses, lodges and student accommodation - if you are kitting out multiple rooms, quality foam at the right price adds up fast. We have commercial buyers who restock with us for exactly this reason.
- A solid main bed on a budget - if money is tight, a high-density sponge mattress beats a sagging spring bed every time.
The RE material edge
One more thing worth knowing. We work with a foam material - what customers around here know as "RE material" - that you will not find at the other shops in town. One of our customers chose us specifically because nobody else had it. It is part of why our foam holds up the way it does. Small detail, real difference.
How long should a sponge mattress last?
A cheap one - under a year before it dips. A quality high-density one - many years of proper support. We build the Comfort to last, which is why it is not the throwaway "sponge" you might be picturing. Pair it with a proper Sleeper Base and you extend its life even further, because a good base stops the foam working against a worn or uneven frame.
What does a sponge mattress cost in South Africa?
This is the best part. A quality sponge bed is the most affordable way into a proper foam mattress. Our Comfort starts from around R2,399 - real high-resilience foam, made in South Africa, not a low-density throwaway. Compare that to what a chain store charges for a spring bed that will sag in three years, and the maths makes itself.
The bottom line
A sponge mattress is a foam mattress - and a good one, built from high-density foam, is a genuinely smart buy. It supports your back, it lasts, and it costs a fraction of what the chains want for something that will not last as long. Just remember the one rule: density is everything. Buy high-density foam from someone who will tell you what is inside it, and a "sponge bed" becomes one of the best-value beds you can own. If you want firmer support, step up to the high-density Active.
Frequently Asked Questions
What is a sponge mattress?
A sponge mattress is a foam mattress made from solid foam with no springs. In South Africa, sponge is simply the common word for foam. A good sponge mattress uses high-density, high-resilience foam that supports your back and holds its shape for years.
Is a sponge mattress good for your back?
A high-density sponge mattress is good for your back because it keeps your spine aligned and supports your weight evenly. A low-density one is not, because it sags and lets your spine bend through the night. Density is what makes the difference.
How long does a sponge mattress last?
A cheap, low-density sponge mattress can start sagging within a year. A quality high-density foam mattress like the Mr Mattress Comfort lasts for years of proper support, especially when used on a solid base.
What is the difference between a sponge mattress and a foam mattress?
There is no real difference - sponge is just the everyday South African word for foam. What matters is the quality of the foam. High-density foam supports and lasts; low-density foam sags. Always ask about density rather than the name on the label.
Ready to feel the difference? Shop foam mattresses factory-direct at mrmattress.co.za - free delivery nationwide, pay over 24 months, 3 to 10 year warranty depending on range.