A Bad Gasket Can Ruin a Window or Door

Ideally, window and door seals operate behind the scenes, unnoticed. However, as seals age and show signs of wear, they can affect the appearance of the whole system. This is particularly true for commercial doors and luxury residential windows with a modern aesthetic – a yellowing gasket is a visual stain on two-tone, glass-and-metal architecture. Here are three reasons your door seal may be ruining the aesthetic of your door – and what you can do to prevent it.

Poor Design


Component design plays a key role in the longevity of a part. A component that slides into the channel but doesn’t grip the race properly can move around, collect dirt and chemicals, and age more quickly. When we see crushed bulb seals that appear smushed in the channel, the problem can often be traced to poor part design. The strength of the bulb, the compression set of the material, and the dimensions of the part all influence how long your seal will appear new.

A thorough design review is the best preventative measure for design flaws. It is important to discuss your door systems and environments with the seal manufacturer so that you will receive a part that is not simply made to print, but designed to work within the specific application.

Material Failure

The best designed seal can look shabby in five years if the material is not perfectly suited to the application. There is no one-size-fits-all solution for window or door seals. TPV, PVC, and EPDM are all frequently used materials for extruded seals, and it is important to discuss the specific application with a trusted seal supplier to ensure that you have the best material for your system. PVC is often chosen for easy color-matching but is considered a poor choice if the application is going to be exposed to temperature extremes. Warm temperatures will accelerate aging in PVC and may lead to warping within the channel. EPDM is a popular cost-effective choice with good elasticity but will generally age at an expedited rate in cold temperatures. 

See the results of a heat aging test comparing PVC and TPV 

For improved ozone resistance, tear strength, and longevity, TPV is a step up from PVC and EPDM. From a performance perspective, TPV can be overkill for certain applications, and therefore is not always necessary. However, TPV is unmatched in its aging resistance, and will retain ‘newly-installed’ appearance and performance for twenty years. TPV also has a distinct visual and tactile advantage – think rubber grips on branded fitness equipment. It is a luxurious feel that makes TPV an excellent choice for some high-end commercial storefronts.

Again, the same preventative measure applies to avoiding material failure: a thorough design review. Considering the entire application, capability needs, and project budget are all functions of a design review that will help manufacturers to avoid unsightly and costly aesthetic headaches in the future. 


A successful seal matches the style of the application to be as inconspicuous as possible. If a window or door system requires a particular color, the manufacturer will likely need to use a PVC or TPV seal – unlike EPDM, PVC and TPV are both easily colorable. For most systems, a standard black or white seal is sufficient. In these cases, color becomes more of a concern of aging resistance. Prolonged exposure to UV light, liquids, and certain chemicals will cause yellowing in white seals and fading in black seals. While a yellowed seal may even function perfectly, it can ruin the look of an otherwise flawless storefront.

Color distortion may not be a major concern for all manufacturers or installers. Additionally, it is usually more noticeable in white seals than in black. However, particularly for storefronts that prioritize aesthetics, this can be an easily overlooked design flaw. If color distortion is a concern, manufacturers should consider materials that have high resistance to aging and UV light exposure. And of course, request a thorough design review with your seal manufacturer!