What is Sponge Rubber?

Sponge rubber, also referred to as expanded foam rubber, represents a unique and highly versatile elastomeric material with a cellular structure that sets it apart from conventional solid rubber materials. This distinctive structure consists of tiny interconnected voids or cells, dispersed throughout the rubber material, which can be either open, or more commonly closed. It’s the presence of closed-cell that gives sponge rubber its exceptional properties and versatility, allowing it to find uses in a broad spectrum of applications and industries. 

Types of Sponge Rubber:

There are many different grades of sponge rubber available, each offering varied characteristics and the ability to meet specific industry needs. Below are some of the most popular types of sponge rubber available from Delta Rubber Limited:

Selecting the most appropriate grade of sponge rubber plays a pivotal role in achieving optimal performance and efficiency. Later, we will explore each grade in more detail, allowing you to make an informed decision as to the most appropriate for your project. 

Why use Sponge Rubber?

Sponge rubber materials offer a unique range of benefits not found with standard solid rubber material and are often selected due to its combination of exceptional qualities that make it an indispensable material. Some of the stand out features of sponge rubber include:

Closed-Cell Structure

The hallmark of sponge rubber is its closed-cell structure, creating a natural barrier that keeps moisture, liquids, gases and other environmental elements at bay. The impermeability makes sponge rubber inherently waterproof, providing a reliable seal that safeguards against liquid penetration. 

Whether used in sealing applications for doors and windows or within gaskets in critical machinery, sponge rubber’s closed-cell structure ensures that it maintains its integrity, effectively isolating the interior from external factors. 


Another key attribute that sets sponge rubber materials apart is its remarkable compressibility, a property that allows it to conform intricately to irregular shapes and surfaces, providing a secure and reliable fit. The material can seamlessly fill gaps and conform to contours to create an airtight seal, all while maintaining structural integrity. 

Often used for gaskets in industrial machinery or as cushioning in electronic devices, the capacity of sponge rubber to absorb and distribute mechanical forces ensures optimal performance. A characteristic that extends product life span and reduces the risk of damage due to external impacts. 

Temperature Resistance

Sponge Rubber’s adaptability extends to temperature extremes, making it a versatile choice for various harsh industrial environments. Depending on the specific type of sponge rubber selected, the material can withstand extreme cold or high temperature conditions without compromising on structural integrity or performance. 

In the aerospace industry sponge rubber ensures the functionality of critical components at freezing altitude temperatures. Whilst in the automotive sector, sponge rubber gaskets are employed in engine compartments where resistance to extreme temperatures is paramount. The materials ability to withstand temperature fluctuations underscores its reputation as a trusted and resilient solution for a multitude of applications. 

What is Sponge Rubber used for?

The versatility of sponge rubber extends its reach to many professional industries, where its unique properties and adaptability cater to specific needs and applications. Let’s explore some of the key sectors and diverse range of uses within each:


Sponge rubber plays a pivotal role in the automotive sector, with applications spanning sealing, cushioning and insulation. It excels in sealing components like gaskets and seals, ensuring airtight closures in doors, windows, hoods and trunks. This prevents moisture intrusion and minimises noises to enhance the overall driving experience.  

The cushioning abilities of sponge rubber help to dampen vibrations in the engine and interior of automotive vehicles, improving passenger comfort and overall vehicle performance. Moreover, it serves as an excellent insulating material, safeguarding components such as wirehing harnesses from extreme temperatures and vibrations, enhancing the reliability of automotive systems. 


In construction, sponge rubber contributes to waterproofing and insulation. Weatherstrips are commonly manufactured from sponge rubber materials to create a reliable seal in windows and doors, bolstering the energy efficiency of buildings. Additionally, sponge rubber is adopted for sealing and gasketing applications, helping to close gaps and joints to prevent water or air infiltration.


Sponge rubber serves the electronics and electrical sector through cushioning, insulation and sealing. The material helps to protect delicate components by effectively absorbing vibrations and shocks, ensuring the longevity and durability of equipment. 

As an insulation material, sponge rubber prevents electric conduction, contributing to safety and compliance. Meanwhile it also provides reliable airtight seals in electrical enclosures and control panels, guarding components against moisture and dust to uphold operational integrity. 


In aerospace and aviation, sponge rubber materials are vital for overall safety and comfort. Ensuring the airtight sealing of aircraft doors, windows and hatches through gaskets and seals. Its thermal insulation capabilities safeguard aircraft systems and components from extreme temperature fluctuations during flights.  

The vibration isolation properties of sponge rubber help to reduce vibrations and absorb shocks, enhancing passenger comfort and preserving structural stability of aircrafts. 

Medical & Healthcare

Within medical equipment manufacturing, sponge rubber enhances comfort and protection. Commonly used as padding in medical devices, beds and seats to provide patient comfort. The material is also utilised as a shock absorber, helping to protect sensitive medical instruments during transportation, preventing damage and maintaining precision and functionality. 

Sponge rubber also helps to create reliable and airtight seals in various medical equipment components, where its unique properties ensure optimum hygiene levels and the prevention of contamination. 

Benefits of Sponge Rubber 

In this section, we’ll uncover the wide-ranging benefits of sponge rubber materials. From its resilience in challenging environments to its overall cost-effectiveness, sponge rubber stands out as a versatile choice for a multitude of applications. 

  • Resistance Properties: Sponge rubber offers exceptional resistance to weather, chemicals and UV radiation. It can ensure harsh environmental conditions while maintaining its integrity. This resistance ensures reliability in even the most challenging settings. 
  • Durability: The durability of sponge rubber materials is a standout feature, extending the lifespan of products and components. Its robust construction allows it to withstand wear and tear, eliminating the need for frequent and costly replacements. 
  • Compression Set Resistance: Sponge rubber resists compression set, maintaining its shape and sealing properties even after extended use. This resilience minimises the risk of leaks and helps to ensure consistent sealing properties. 
  • Versatility: The versatility of sponge rubber materials lies in their adaptability and customisation options. At Delta Rubber Limited we can tailor properties to meet specific needs, making different materials suitable for a wide range of applications across various professional industries. 
  • Cost-Effectiveness: Sponge rubber provides many projects with a cost-effective elastomeric solution, without compromising on overall quality. Its durability and ability to create reliable seals, absorb impacts and insulate against temperature variations contributes to long-term cost savings. This makes it an attractive choice for many applications and industries. 

What are the Different Types of Sponge Rubber?

Sponge rubber’s adaptability extends beyond its core properties, with various specialised grades available, each tailored to meet specific demands and applications. Here are some of the most common grades available, all available off-the-shelf from Delta Rubber Limited:

Expanded Neoprene/EPDM Sponge Rubber

Expanded Neoprene/EPDM Sponge Rubber boasts a versatile profile, combining the robustness of Neoprene with EPDM’s outstanding weather resistance properties. This combination results in a material that excels in outdoor applications, such as weatherstripping for doors and windows, where it seals effectively against moisture and drafts. Its durability also makes it suitable for automotive & aerospace gaskets and seals. 

  • Hardness: 36 ± 5° Shore A
  • Temperature Range: -40°C to +70°C
  • Elongation at Break: >180%
  • Compression Set: 19.1%
  • Tensile Strength: >500 [MPA]

Silicone Sponge Rubber 

Silicone Sponge Rubber is prized for its exceptional temperature resistance properties and versatility, including its FDA approval. It thrives in high-temperature environments, making it ideal for applications in industries like aerospace and electronics. The compressibility and resistance to extreme temperatures ensures longevity and reliability in demanding settings. Due to the materials FDA approval, it’s often the go-to choice for medical, pharmaceutical and food processing applications. 

  • Hardness: 42 ± 5° Shore A
  • Temperature Range: -60°C to +200°C
  • Elongation at Break: 145%
  • Compression Set: 14.5%
  • Tensile Strength: 0.6 [Nmm2]

HT800 Silicone Sponge Rubber 

HT800 Silicone Sponge Rubber is a specialist variant of Silicone Sponge Rubber, featuring flame retardant capabilities. The material is a highly versatile, medium firmness silicone that offers the lightness of foam, with the enhanced sealing capabilities of traditional sponge rubber. Commonly used due to its ability to protect against wind, rain and fire, the material is often used for outdoor applications. 

  • Hardness: /
  • Temperature Range: /
  • Elongation at Break: 80%
  • Compression Set: <5 @100°C
  • Tensile Strength: 310 [kPA]

Viton Sponge Rubber 

Viton Sponge Rubber is renowned as one of the most durable and high-performance sponge rubber materials on the market, offering exceptional chemical and fluid resistance, making it the preferred choice for gruelling chemical processing or oil and gas applications. The sponge rubber material is manufactured with a continuous skin on both sides for improved strength and tear resistance, even if punctured, the material acts as an impenetrable barrier, preventing the passage of air or fluids through cells.

  • Hardness: /
  • Temperature Range: -24°C to +205°C
  • Elongation at Break: /
  • Compression Set: 27%
  • Tensile Strength: /

PVC/Nitrile Sponge Rubber 

PVC/Nitrile Sponge Rubber strikes a balance between durability and cost-effectiveness. A high-quality material that is classified under BS 476 Class 0 building regulations to protect surfaces from the spread of flames, limiting the amount of heat released from a surface during a fire. The material also offers excellent chemical, oil and grease resistance properties, making it a popular sponge rubber choice for automotive and other oil-rich environments

  • Hardness: /
  • Temperature Range: -50°C to +116°C
  • Elongation at Break: /
  • Compression Set: /
  • Tensile Strength: /

What can you buy Sponge Rubber? 

As leading UK manufacturers and worldwide suppliers of sponge rubber, at Delta Rubber Limited we have a vast range of Neoprene rubber in stock at our Dorset headquarters including Expanded Neoprene/EPDM Sponge Rubber, Silicone Sponge Rubber, HT800 Silicone Sponge Rubber, Viton Sponge Rubber and PVC/Nitrile Sponge Rubber. 

Our Sponge Rubber range is sold by the roll, in sheet form or manufactured to bespoke components such as cut-rubber strip, gaskets, washers, seals, extrusions, and O-rings if required. Our access to state-of-the-art manufacturing equipment, combined with our 90 years industry experience allows us to offer a level of service unrivalled in the industry. For more information on our manufacturing capabilities click here

  • Expanded Neoprene/EPDM Sponge Rubber – Available in sheet form from 1mm to 25mm, sheet sizes measuring 1 metre wide and any length from 1 metre to a full 10 metre roll. Our Expanded Neoprene/EPDM Sponge Cut Rubber Strip range features a range of widths from 10mm to 300mm, thicknesses from 1.5mm to 25mm and sold in lengths of either 5 or 10 metres. Our cut rubber strip range is available plain or with self-adhesive
  • Silicone Sponge Rubber – Silicone Sponge Rubber is sold in strip form, with any width from 10mm to 50mm available, thicknesses from 1.5mm to 6mm and standard lengths of 5 metres. The high quality sponge material is sold with self-adhesive or plain. Silicone Sponge Rubber Sheet is available upon request. 
  • HT800 Silicone Sponge Rubber – We stock and sell HT800 Silicone Sponge Rubber in sheets measuring 915mm wide, thicknesses from 0.8mm to 4.2mm and any length from 1 metre to a full 10 metre roll. Our HT800 Cut Rubber Strip is with self-adhesive, in widths from 10mm to 50mm & lengths of 3 metres. 
  • Viton Sponge Rubber – We are a UK exclusive stockist of Viton Sponge Rubber and offer the high-performance material in standard sheet sizes measuring 1422mm long, 710mm wide and 3.18mm thick. Custom sizes and variations in thickness are available upon request. 
  • PVC/Nitrile Sponge Rubber – PVC/Nitrile Sponge Rubber is sold online in cut strip form, choose any width from 12mm to 150mm, thicknesses from 3mm to 25mm and lengths of 8, 10 or 14 metres. The specialist sponge rubber material is sold with self-adhesive backing as standard, for alternative sizes or plain material, please contact us with your enquiry.