Window films are used for a variety of purposes, whether it’s to provide glare reduction, solar energy improvement, visual privacy, safety protection, to attenuate RF and IR energy, or simply to help decorate or brand a property. One question that is commonly asked is: Can window films be layered so that multiple benefits are combined?

The answer: Yes, but it should only be considered under the right circumstances and conditions.
Layering window films, or dual application, is the process of placing one film on top of another film. It’s a practice that’s typically carried out when a customer has specific needs that aren’t met by just one film. In this post, we’ll take a look at some of the common situations where dual application makes sense and what property owners, and managers should know before installing layered film on their glass.

When Does Dual-Application Make Sense?

Only under the right circumstances. Dual application commonly occurs when a customer wants to alter the visual appearance of the windows so they look more aesthetically pleasing, or to provide visual privacy, after an initial layer of film is installed. Some common examples include:

  • Pairing safety films that protect against glass fragmentation or blast, with decorative films to take on a more appealing appearance after installation. Most safety films are clear, requiring an additional film if a very specific appearance is required.

  • Pairing safety films with blackout or opaque films as a means of providing visual privacy or protection through the glass.

  • Pairing RF or IR films with decorative films or security films.

Dual Application Pitfalls

However, while dual application can make sense and can be a somewhat common request, there are some drawbacks that property managers and owners should be aware of before layering window films.

  • It voids the warranty: Most window films come with a factory warranty but applying films in multiple layers will likely void warranties for both films.

  • Longer dry times: Due to the increased thickness, longer durations are required for the application water and adhesive to cure and dry.

  • Cleaning challenges: When a second layer of film is applied, a different cleaning method needs to be performed — and this method can impact the surface preparation. When this occurs, it is possible for debris or other contaminants to get trapped especially between the two layers.

  • Increased thermal stress: Finally, multiple layers of film can lead to increased thermal stress placed on the window glass. While this is mostly well within the safety parameters, the dual application should still be reviewed prior to installation.

The bottom line is that while layering window films is common, it is important to make sure that the benefits outweigh any potential drawbacks before making the decision to perform this on your interior or exterior glass.

Choosing the right window film for your particular scenario can be complicated. Let the experts at Signals Defense help.