Polymer degradation and sofas: why foam cushions go flat
Posted posted on July 20, 2026
Why do so many sofas begin life looking plump and enticing, then slowly turn into something a bit sad and flat? Generally, it’s because the sofa is full of foam…
…More precisely, polyurethane foam: the synthetic, petrochemical cushioning material used in huge quantities across the modern furniture industry. It is light, cheap, easy to cut and easy to shape, which is why it’s practically everywhere.
The trouble is that foam is a material with a particular cellular structure…one that quite quickly gets tired.
Some sofa science...
Polyurethane foam is a polymer, which means it is made from long chains of molecules, joined together to create a material with certain useful properties, such as softness, springiness, support and flexibility.
In a foam cushion, those polymers form a cellular structure: a tiny open network that traps air and gives the cushion its bounce. When the foam is new, that structure is perfect for sofa comfort: when you sit down, it compresses and then springs back.
But over time, the foam is repeatedly compressed, by the simple business of being sat on. The little internal struts and walls of the foam begin to fatigue. The material can also be affected by oxygen, heat, moisture and light. Gradually, the foam loses some of its original firmness and resilience.
This is why a sofa cushion can start to look dipped or hollowed out, and why that loss of shape can’t just be fixed with a quick plump.
The material itself may no longer be capable returning to the shape it once had. That is the practical result of foam fatigue and polymer degradation: the bounce and the shape are gradually depleted… and the sofa general ends up in landfill or the incinerator.
The problem with plastic, and what Schplendid uses instead
A foam sofa is often built around convenience: convenient for the factory, convenient for the margin, convenient for a neat showroom look on day one.
But what matters to us is what happens on day 1,000. And day 3,000, for that matter.
So we build them in a completely different way. Inside a Schplendid sofa, you will find traditional and natural upholstery materials: coconut husk, natural latex, sheep’s wool and goose down, supported by 8-way hand-tied springs.
The coconut husk gives structure and breathable support, while the natural latex adds elasticity. The wool adds softness, comfort, natural temperature regulation and natural fire resistance. And down is, frankly, one of the comfiest substances on the planet, giving that lovely, yielding, cloud-like feeling that synthetic fibre struggles to imitate.
Now, polymer degradation of some sort applies to everything including natural materials, so these things aren’t immortal, but the practical effects over are a world away from plastic. Natural materials do age, but they settle, and can easily be maintained for a very long time.
A goose down cushion, for instance, does need plumping from time to time – but that’s a big difference from a sofa whose foam core has permanently lost its bounce.
On top of that, we use our natural upholstery materials as layers, rather than as sealed plastic blocks, meaning they can be revived, adjusted, repaired and, one day, replaced.
This is an older, better way of making furniture: a proper upholstery system, with resilient materials working together.
Plastic foam became the normal way because it was cheap, convenient and easy to sell. We think sofas can be better than that. They can be made from wonderful natural materials, with the sort of care and craft that means they don’t start giving up after a few years.
Or, to put it another way, this is all part of the great sofa de-schittification… and our campaign for real upholstery (watch this space).
Polymer degradation and sofas: why foam cushions go flat
Why do so many sofas begin life looking plump and enticing, then slowly turn into something a bit sad and flat? Generally, it’s because the sofa is full of foam…
…More precisely, polyurethane foam: the synthetic, petrochemical cushioning material used in huge quantities across the modern furniture industry. It is light, cheap, easy to cut and easy to shape, which is why it’s practically everywhere.
The trouble is that foam is a material with a particular cellular structure…one that quite quickly gets tired.
Some sofa science...
Polyurethane foam is a polymer, which means it is made from long chains of molecules, joined together to create a material with certain useful properties, such as softness, springiness, support and flexibility.
In a foam cushion, those polymers form a cellular structure: a tiny open network that traps air and gives the cushion its bounce. When the foam is new, that structure is perfect for sofa comfort: when you sit down, it compresses and then springs back.
But over time, the foam is repeatedly compressed, by the simple business of being sat on. The little internal struts and walls of the foam begin to fatigue. The material can also be affected by oxygen, heat, moisture and light. Gradually, the foam loses some of its original firmness and resilience.
This is why a sofa cushion can start to look dipped or hollowed out, and why that loss of shape can’t just be fixed with a quick plump.
The material itself may no longer be capable returning to the shape it once had. That is the practical result of foam fatigue and polymer degradation: the bounce and the shape are gradually depleted… and the sofa general ends up in landfill or the incinerator.
The problem with plastic, and what Schplendid uses instead
A foam sofa is often built around convenience: convenient for the factory, convenient for the margin, convenient for a neat showroom look on day one.
But what matters to us is what happens on day 1,000. And day 3,000, for that matter.
So we build them in a completely different way. Inside a Schplendid sofa, you will find traditional and natural upholstery materials: coconut husk, natural latex, sheep’s wool and goose down, supported by 8-way hand-tied springs.
The coconut husk gives structure and breathable support, while the natural latex adds elasticity. The wool adds softness, comfort, natural temperature regulation and natural fire resistance. And down is, frankly, one of the comfiest substances on the planet, giving that lovely, yielding, cloud-like feeling that synthetic fibre struggles to imitate.
Now, polymer degradation of some sort applies to everything including natural materials, so these things aren’t immortal, but the practical effects over are a world away from plastic. Natural materials do age, but they settle, and can easily be maintained for a very long time.
A goose down cushion, for instance, does need plumping from time to time – but that’s a big difference from a sofa whose foam core has permanently lost its bounce.
On top of that, we use our natural upholstery materials as layers, rather than as sealed plastic blocks, meaning they can be revived, adjusted, repaired and, one day, replaced.
This is an older, better way of making furniture: a proper upholstery system, with resilient materials working together.
Plastic foam became the normal way because it was cheap, convenient and easy to sell. We think sofas can be better than that. They can be made from wonderful natural materials, with the sort of care and craft that means they don’t start giving up after a few years.
Or, to put it another way, this is all part of the great sofa de-schittification… and our campaign for real upholstery (watch this space).
See also:
Naturally luxurious: Why we upholster our sofas with coconut and wool instead of foam
Ten Things the Sofa Industry Would Rather You Didn’t Think About