Silicone Sponge Vs Silicone Foam: What Is The Difference?

February 1, 2024

Silicone Sponge and Silicone foams have a wide range of applications. Their functions include waterproofing, insulating, sealing, cushioning, or providing comfort. However, there are some differences between the two, and their applications vary accordingly. 

Generally, silicone sponges are denser, stronger, heavier, and heat–resistant than silicone foams. Meanwhile, the silicone foam’s properties include flexibility, compressibility, breathability and flame retardation. 

To get the best result with a project, you must know whether to use the silicone foam or the sponge. Find out in this following discussion and make the correct choice. 

The Differences Between Silicone Foam And Silicone Sponge 

It’s easy to get confused when you shop for silicone appliances. For instance, both foam and sponge sound very similar. We often use them interchangeably. However, Silicone Foam and Silicone Sponge are much different from one another. Here’s an explanation that will clear all your confusion for good.

Structural Difference 

The most significant difference between the Silicone sponge and foam is in their structures. Both products are closely knit networks of silicone cells. However, in Silicone sponges, it’s a closed cell structure. Therefore, gas and moisture can’t seep through it. In comparison, Silicone Foam is more permeable since it has an open cell structure. 

As a result, Silicone Sponges are the best choice when you have to airtight or waterproof something. On the other hand, Silicone foam’s lightweight build makes it an ideal shock absorber. They can also be used to make flexible multi-variety tubes.

Density And Softness 

Silicone Sponge is denser than Silicone Foam. It can maintain its thickness under extreme pressure. This also means Silicone Sponge is more stable. Plus, it’s stronger regarding how much weight both products can support. However, the density of the Silicone Sponge might add up and make a design heavier than it should be. 

The softer Silicone Foam tears and abrades more easily. But its softness gives it the advantage to adapt to the surrounding structure quickly. Therefore, Silicone Foam is excellent for applications that require precise fitting. It’s also more compressible than Silicone Sponge. So, you can pressurize it to create watertight seals. 

Temperature And Flammability 

Silicone Sponge has a higher tolerance to heat than Silicone Foam. For instance, it can perform fine even at a temperature of 500F. In comparison, Silicone Foam starts failing before 400F. As a result, a silicone sponge is better at preventing thermal transfer. Thus, it can serve as an excellent insulator. 

Meanwhile, Silicone Foam is the better flame-retardant material of the two. It meets the UL 94 V0 standard. This is the highest rating for anti-flammability. The rating indicates that Silicone Foam can self-extinguish a flame and prevent the spread of fire. There are also specially designed non-flammable Silicone Sponges offered by some manufacturers.

Where Should You Use Silicone Sponge?

From our discussion, it’s understandable what the possible best applications of Silicon Sponge might be. When you need more stability and protection, you use a silicone sponge. Its uses include lighting seals, HVAC gaskets, Aerospace insulation, etc.

Protecting Outdoor Lighting

Street lamps and traffic lights are exposed to scorching sun, rain, and storms. A silicone Sponge can be the perfect sealing material for these fixtures. The high heat resistance of Silicone Sponge protects the light from sunlight. It also prevents the entry of rain or melting snow due to its waterproofing capabilities. 

HVAC Gaskets 

Ducts, pipes, and valves make up our air conditioning systems. These components have to deal with unpredictable heat and moisture conditions. Silicone sponges can make excellent gaskets for these HVAC components. The result is better insulation, vibration, and noise reduction. 

Aerospace Insulation 

Rockets, Satellites, and Aircraft are frequently exposed to excessive temperature and impact. This can affect the sensitive equipment inside these vessels and sabotage their missions. Silicone Sponge can protect the equipment from heat and radiation in these cases. Plus, it can also provide some added cushioning. 

Sealing Electrical Panels and Junctions 

It’s essential to protect the delicate wiring and circuit system from external factors. Excess heat can mess up the circuit systems and cause them to malfunction. Meanwhile, moisture can cause rust and corrosion on the wiring. Silicone sponge seals can prevent this and keep control panels and junction boxes in crisp condition. 

Medical Applications 

The prosthetics and prosthetics need cushioning that is flexible yet maintains stability under pressure. Silicone Sponge can be the perfect material in this case since it’s spongy but still has limited compressibility. Plus, medical-grade Silicone Sponge has excellent biocompatibility. It also has applications in surgical instrument protection since it doesn’t soak fluids like foam. 

Where Should You Use Silicone Foam?

Silicone Foam has three advantages over Silicone Sponge. It’s softer, better shock absorbent, and more flame retardant. As a result, Silicone Foam is used in applications where those are mandatory requirements. 

Where Should You Use Silicone Foam

Bedding Items 

Your mattress and pillows owe their fluffiness to Silicone Foam. Being soft and compressible, it can easily adapt to a person’s weight and body shape.

To compare, Silicone sponges wouldn't make good bedding items. Firstly, its hardness would make it very uncomfortable to lie on. Secondly, It doesn't allow the thermal transfer. Therefore, heat and sweat will be trapped in the mattress. 

Kitchen Ware

Silicone foam serves as a heat-resistant and non-stick surface in many kitchen appliances. These include spatulas, baking mats, muffin pans, etc. 

It’s the material of choice because it can withstand temperatures up to 400F. Plus, it doesn’t release any toxic fumes when exposed to extreme heat. You should also consider that it’s flame retardant and, thus, is safer to work with around fire. Another example of Silicone foam in the kitchen is oven gaskets

Underwater Gear 

Swimming gear such as goggles and diving masks use silicone foam for its sealing capacity. Silicone foam is readily compressible and adjusts to the surface it's pressed on. As a result, it can create excellent watertight seals that divers need in their gears. Plus, its softness and breathability make the gears comfortable for the user.

Sports Gear 

The softness and shock-resisting properties of the Silicone Foam have driven sports manufacturers to choose it as a cushioning material. Helmets and gloves are padded with silicone foam. It makes these sports gears more resistant to impact. At the same time, the players can also wear them comfortably for long hours. 


Silicone foam and Silicone sponge both have important applications in our daily lives. However, you must know their correct applications to get the best results. Our experts at NanFang Rubber can help you with any queries you have.