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Perma-Fit™ Slideout Seals

To purchase please contact your local RV Dealer.

Perma-Fit™ is an advanced technology, non-cellular thermoplastic vulcanate polymer (TVP) now available that outperforms EPDM extrusions commonly used in slide-outs. Such EPDM seals are often over compressed by manufacturers seeking a tighter seal. The open cell structure of EPDM seals is not made to be compressed more than 30 percent, but manufacturers may compress the seal by as much as 70 percent in slide-out applications. In this case, the open cell structure of EPDM seals will quickly break down, causing the seal to fail, with leaking the likely consequence. The seals can also shrink and become brittle.


Seal Design came up with a solution by introducing slide-out bulb seals and wipe seals that can be compressed up to 70 percent and still hold up for the life of the RV.  TPV has no cell structure that can break down. Since there are no air pockets to collapse, compression set will never take place and the seal will bounce back without compromise. As a result, Perma-Fit extrusions for slide-outs are more elastic and durable and perform well for a long time.


EPDM extrusions are cellular in nature with small pockets of air in the rubber. Over time, the cells break down (burst) and the pocket collapses thereby losing it's "bouce back" capabilities. Permanent compression results, the seal is compromised and leaking is the likely consequence.



Used by all automobile companies for door seals, thermoplastics have no cells, there are no pockets of air to collapse and compression set will never take place. As a result, Perma-Fit extrusions will seal as well after 20 years as they do day one.


TPV extrusions are used extensively by the automotive industry, where they have been proven to be extremely durable and high quality, working as well after 20 years as they do on day one. Perma-Fit is the only extrusion of this kind for RV use.

Thermal Bonding Tapes

Perma-Fit can be attached using the standard clip system or by Seal Design’s proprietary thermal bonding system with heat-activated acrylic tape systems (HATS) designed specifically for TPV materials, which provides a much more reliable bond than standard tapes.

Wipe Seals

As for slide-out wipe seals — they are subject to a different type of stress and damage … friction. When the slide-out drags across the wipe seal the seal exerts considerable drag and friction to squeegee water off the slide out surface. EPDM has a relatively high surface tension because its surface is rough. The result is catching, tearing and wear that compromises the seal and allows water into the coach. Seal Design applies a slip coat, which reduces the surface tension of its slide out seals. It provides a very smooth, low friction wiping action that provides a reliable, longer lasting seal.

More Features and benefits of TPV extrusions

Feature Benefit
Excellent ozone, water and temperature resistance. Maintains performance no matter what the climate or weather situation.
Will not chalk with UV exposure Maintains attractive apparence over time.
Energy Star, AAMA tested, approved and rated. Assures energy efficiency and that it's harmless to the environment.
Manufactured under TS16949/ISO 9000 automotive certifications. Will not out-gas or chalk and is much cleaner for the environment.


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Seal Design and Dicor Corporation focus on the people and companies that use our products. This includes products, support and services that help improve the production process.

  • Perma-Fit slide-out seals require no significant changes in the manufacturer’s production process to use. The material is also recyclable, yielding overall part cost reductions.
  • Only one supplier source needed, even if using several different profiles.
  • Manufacturers can benefit from overall part cost reductions because of recyclability. There’s no production line stoppage because product has indefinite shelf life.
  • Seal Design will audit the extrusion needs of customers to identify potential cost savings, installation improvements, and problem solving solutions. Plus we will conduct cycle counts and help with inventory management.