What Is Wet Glazing, and Why Security Film Needs It

Security film gets sold as a lot of things it is not. It is not bulletproof, and on its own it is only half the job. The other half is wet glazing, the step that ties the film to the window frame. Here is what it is, why we do it on every security film install, and what to expect when it goes on.

What security film actually does

Security film is a thick, clear film applied to the inside of the glass. When the glass breaks, the film holds the pieces together instead of letting them fall out or fly.

It is designed to slow entry, not stop it forever. The goal is to turn a smash-and-grab that takes seconds into a fight with the glass that takes minutes, long enough for police or security to respond. It is not bulletproof.

What wet glazing is

Wet glazing is a structural sealant run around the edge of the window. It bonds the film to the frame, so if someone tries to break in, the glass stays put even after it shatters. That is what prevents entry.

Without it, the film holds the broken glass together but nothing holds the glass in the opening. A few hard kicks or hits can push the whole sheet of filmed glass out of the frame in one piece. Wet glazing closes that gap, which is why we wet glaze every security film install.

How it goes on, and how long it takes

1. The film goes on first and has to dry for several days before the wet glazing can be added. Film makers' own install guides say the same: the edge is sealed only after the film is completely dry.
2. Then the structural silicone. We use Dow 995, a silicone made for structural glazing. A bead goes around the perimeter of each pane, bonding the film to the frame.
3. Then it cures. Dow 995 skins over in about an hour, but it takes 7 to 14 days to cure and 14 to 21 days to reach full adhesion, based on Dow's numbers at 77°F and 50% humidity. Cold weather slows it down.

So plan on two visits, and plan on the system reaching full strength a few weeks after the second one.

What to expect while the film and sealant cure, how to inspect the job and how to care for it after: download our window film guide (PDF).

Doors are different

Doors take more abuse than windows, and they're built differently. Most commercial doors hold the glass in with removable glazing stops and compression gaskets. That stop has too short a profile to give silicone enough to grab onto, and a bead of silicone there bonds the film to the stop, not to the door frame. Once the glass breaks, a few kicks can push the filmed glass and stop right out of the door.

Doors should always get a ZSecure attachment instead of wet glazing. It's a custom-shaped aluminum frame made to fit each door. One side bonds to the glass and film, and the other fits over the glass stop and bonds to the door frame itself. If the glass breaks, the filmed glass stays in the door, so the door can't easily be kicked in.

A few more things worth knowing about it:

• It's made to fit each door's size and style, and it's close to invisible once it's on.
• It can be added to doors that already have security film.
• ZSecure reports passing ANSI Z97.1 impact testing, which checks that the filmed glass stays in the frame on impact, and ASTM E330 accelerated weather testing.

Windows that are not good candidates

Not every window is a good fit for security film. We will tell you up front rather than sell you something that will not perform:

• French pane and divided-lite windows, with many small panes split by thin bars.
• Plastic, acrylic or polycarbonate panes. Window film is made for glass.
• Glass that is already cracked or chipped, or insulated units with failed seals (fogging between the panes). Fix or replace those first.
• Textured, patterned or wired glass, where film can't lie flat and bond evenly.
• Frames in poor condition. The attachment is only as strong as the frame it bonds to.
• Doors with wood glass stops, which aren't built to take an attachment system unless the glass is set in a metal frame.

Quick Questions

Is security film bulletproof?

No. It is designed to slow entry so police or security can respond.

Can wet glazing be added to existing windows?

Yes. It goes on your existing glass and frames after the film is installed and dry.

When is it at full strength?

The silicone reaches full adhesion about 14 to 21 days after it goes on, longer in cold weather.

What about the doors?

Doors get a ZSecure attachment to the door frame instead of wet glazing.

What Does Your Building Need?

Send us photos of the glass, doors and frames, and we will tell you what makes sense for your building. Request a quote