Sponge Rubber Seals
Sponge rubber seals are manufactured from sponge rubber materials, such as expanded EPDM or expanded neoprene. These compressible materials are manufactured into extruded profiles in a large range of shapes and sizes designed to offer a solution to most sealing problems. They can be used for almost any application that requires a seal to stop the ingress of water, air or dirt. As expanded EPDM and expanded neoprene are a type of closed-cell sponge rubber they will not absorb water or moisture.
Extruded sponge rubber seals are manufactured with a matt skin that gives the section a clean aesthetic appearance. They are often extruded with a hollow centre or external fin that aids compression when installed in environments that have low closing forces. All of these sections serve different purposes and offer different levels of compression and recovery.
As sponge seals require compression to create watertight seals, they can be damaged with excessive and prolonged force. Compression set can be avoided by installing the correct seal for the size of gap you are looking to fill. We recommend fitting a sponge rubber section that is approximately 30% bigger than the size of the gap. For example, to seal a 10mm gap you should look to use a section that is around 15mm high.
All Sponge SealsFrequently Asked Questions
What are sponge rubber seals?
Sponge rubber seals are flexible and compressible sealing strips manufactured from expanded rubber compounds such as EPDM and neoprene. They are manufactured with a closed-cell cellular structure that allows them to compress easily when fitted between two surfaces. This creates an effective barrier against air, water, dust and vibration.
They are commonly used around doors, access panels, machinery covers and vehicle compartments to provide cushioning and weather protection. The compressible nature of sponge rubber makes these seals particularly effective on irregular or uneven surfaces where there is not an even closing gap.
How much should sponge rubber seals be compressed?
To achieve optimal performance, sponge rubber seals should typically be compressed by around a third of their original height or thickness. This level of compression helps create a secure and long-lasting seal that does not overstress the material through prolonged over compression. For example, if the sealing gap measures 5mm, a sponge rubber profile of about 7–9mm thick is recommended.
Under-compression can cause air or water leaks, while excessive compression may lead to permanent deformation (known as compression set). This overtime can reduce the seals effectiveness. The actual compression required may vary depending on the shape of the seal, the rubber grade and the hardness of the material.
Why are some sponge rubber seals hollow?
Some of our sponge rubber profiles are manufactured with a hollow centre that aids compression when used in applications that have low closing forces. These profiles feel softer than ‘solid’ sponge rubber seals and can sometimes be compressed by slightly more than the recommended 30%.
Can sponge rubber seals be for outdoor applications?
Yes, most sponge rubber seals—especially those made from EPDM and neoprene—are well suited for outdoor use. These materials resist damage from sunlight, ozone and temperature extremes. This makes them ideal for sealing exterior panels, doors and hatches. EPDM offers excellent UV and weather resistance, while neoprene offers a small degree of protection against oils and chemicals.
If the seal includes an adhesive backing, ensure it’s designed for outdoor use or protected from prolonged exposure to moisture, as certain adhesive backings are intended only for indoor or sheltered conditions. For these applications, it is sometimes preferable to use a plain sponge rubber profile with a separate waterproof contact adhesive.
How should sponge rubber seals be installed?
Installation will depend on whether the sponge rubber seal is plain or has an adhesive backing. If you are looking to install a plain profile, this should be fitted using either a contact adhesive, double-sided tape or by pressing the profile into a suitably sized channel. Before installation, clean the application surface thoroughly to remove any dust, oil or loose particles to ensure good adhesion and a reliable seal. Allow adhesives to cure fully before the seal is compressed or exposed to the elements.
For self-adhesive profiles, simply peel away the backing strip and press the seal firmly into place along the required surface. It is important to avoid stretching the seal during fitting.
How would I cut a sponge rubber seal?
Sponge rubber seals are easy to trim to your required length. They can be cut cleanly with a sharp knife or utility blade. As sponge rubber has a cellular structure, cut slowly and evenly without compressing the material. This should ensure a smooth square edge.
These profiles can also be cut at angles to make frames of a particular width and height. This makes it simple to fit seals precisely around doors, windows and custom enclosures without the need for specialist tools.
What is the lifespan of a sponge rubber profile?
The lifespan will depend on the initial installation and environment. When correctly installed and maintained, sponge rubber seals offer a long service life—often lasting several years, even in demanding conditions. However, their durability depends on the rubber type and the environmental exposure.
EPDM sponge rubbers have the best resistance to UV radiation, ozone and temperature variation, giving them superior longevity compared to many other sealing materials. Regular inspection and cleaning will help extend their lifespan further.