Choose a sponge rubber seal when the door closes with low force, the gap is uneven, or the seal must compress a lot. Choose a solid rubber seal when it must resist wear, impact, tearing or high pressure. Many door and hatch seals combine both: a solid base for fixing and a sponge bulb for sealing. Walker Rubber extrudes sponge and solid seals in EPDM, neoprene and silicone in Norwich.
Not sure which seal your door needs? Send us the gap and closing force.
What is the difference between sponge and solid rubber?
Solid (dense) rubber is fully compact. It is tough and wear-resistant, but it takes more force to compress.
Sponge rubber has a cellular structure made by a blowing agent during curing. It compresses easily and recovers, so it seals uneven gaps at low closing force.
- Closed-cell sponge has sealed cells. It doesn’t absorb water, so it’s the right choice for door and hatch seals.
- Open-cell sponge (foam) has linked cells. It absorbs water and air, so it suits cushioning and acoustic uses, not watertight sealing.
Sponge vs solid: how do they compare?
Factor | Sponge (closed cell) | Solid (dense) |
Closing force needed | Low | Higher |
Copes with uneven gaps | Very well | Less well |
Compression range | Large, often 30–50% | Small, usually 15–30% |
Abrasion and tear resistance | Lower | High |
Resistance to impact and foot traffic | Poor | Good |
Water and dust sealing | Good, if closed-cell | Good |
Typical uses | Enclosure doors, cabinets, vehicle doors, hatches | Container doors, gates, high-traffic doors, glazing |
Compression ranges are typical design guidance, not specifications for a particular profile.
When should I use a sponge seal?
- The door or lid is closed by hand, or by light latches.
- The gap varies around the frame, so the seal has to fill high and low spots.
- The panel is thin and would bow under a stiff seal.
- You need thermal or acoustic insulation as well as sealing.
When should I use a solid seal?
- The seal is walked on, driven over or hit by loads.
- The door slides across the seal, so it needs to resist abrasion.
- The seal must hold back water pressure, as in flood gates or tank hatches.
- The seal is pushed into a channel and must grip firmly.
What about combined sponge and solid seals?
Combined profiles have a dense rubber base or clip and a sponge bulb or lip. The dense part fixes the seal securely, and the sponge part does the sealing. They are common on enclosure doors, vehicle doors and marine hatches.
Which sponge material should I choose?
Material | Best for | Watch out for |
EPDM sponge | Outdoor doors, hatches and enclosures: weather, UV, water | Poor with oils and fuels |
Neoprene sponge | General industrial and marine: some oil, good fire behaviour | Less UV-stable long-term than EPDM |
Silicone sponge | High or low temperatures, food areas, ovens, low compression set | Lower tear strength and higher cost |
How do I specify a door seal?
- Measure the gap with the door closed, at several points around the frame.
- Note the closing method: by hand, latch, compression clamp or automatic.
- Measure the fixing: channel width, flange thickness for a clip-on seal, or a flat face for self-adhesive.
- List the environment: outdoor, temperature, oil, cleaning chemicals, fire requirements.
- Say what it must keep out: dust, rain, jetted water or pressure.
How does Walker Rubber compare?
| Walker Rubber | Typical catalogue supplier |
Sponge and solid profiles | Both, in EPDM, neoprene and silicone | Usually standard sizes only |
Custom profiles | Die made in-house, samples can be available in 72 hours | Not offered, or outsourced |
Lengths | 1 m to 10,000 m, cut to length | Fixed coils |
Self-adhesive backing | Available | Sometimes |
Moulded corners and frames | Available | Rarely |
Frequently asked questions
Is sponge or solid rubber better for a door seal?
For most hand-closed doors and enclosures, closed-cell sponge seals better because it compresses easily and fills uneven gaps. Use solid rubber where the seal takes wear, impact or pressure.
What is the best material for an outdoor door seal?
EPDM. It resists UV, ozone and rain for years, and is available in both sponge and solid grades.
Is foam rubber the same as sponge rubber?
People often use the terms interchangeably. In sealing, “sponge” usually means closed-cell rubber that doesn’t absorb water, and “foam” often means open-cell material.
Why won’t my door close properly after fitting a new seal?
The seal is probably too large or too dense for the gap. A sponge seal or a smaller section will lower the closing force.
How long do sponge door seals last?
It depends on material and compression. Closed-cell EPDM and silicone sponge seals typically last many years outdoors when sized to compress about 30–50% rather than flat.
What is silicone sponge used for?
Silicone sponge seals doors and hatches that see high or low temperatures, and food or pharmaceutical areas. It keeps its shape well under long-term compression.
Get the right door seal
Send us your gap size, closing method and environment, or a sample of your old seal.