Experience with window "security film"?

[McNutty]

My house has what is referred to around here as a "daylight basement", which, in case that's a regional term, means the basement isn't actually sunken very far into the ground (maybe 3 feet), and as a result can (and does) have large windows at ground level. These are somewhat of a security concern, since someone in the backyard isn't visible from the street and has a nice large window at kicking height that's super easy to climb in through.

I've heard of stuff called "security film" that is basically a coating that makes it difficult to break out a window -- you can break the glass, but it stays in an intact sheet so you can't actually get through it. I'm considering putting this on these basement windows. But I have some questions about it, and I thought someone here might have some input.

1) Does it really work?
2) Is it something you'd put on yourself, or is it like window-tinting, where DIY jobs tend to end up looking crappy?
3) So the glass stays intact as one big sheet when broken, but what actually keeps it from just coming out of the frame at the edges? Does the installation procedure somehow bond it to the frame as well? If so, does this make it a nightmare to replace the glass if it does get cracked?

[Peeta Mellark]

We put this on a cabin my parents own. It's easy to put in yourself and it will keep the glass together, but it does knock out of the frame if there's enough pressure. The main things the DIY stuff is good for are protecting your house from shattered glass in the case of damage to the window, or on a window you're worried about kids running into and hurting themselves on. I don't think I'd trust it for anything else, really.

If you have professionals do it, they could integrate it with the frames, but then like you said it might be a huge pain in the ass to replace the glass if something happens. The film also collects scratches like crazy, just to warn you. However, it makes the glass amazingly strong and if it was integrated into the frame someone would have to be really determined to get through it. Like beating it with a hammer for a good long time.

[CatInASuit]

Yes, it does work, having sat in an office and watching them bomb-proof windows with a variant of the stuff it is amazingly good at what it does. I don't think the shop bought one will be quite as good but the same principles apply.

It should be fairly easy to put on, it's effectively a large sheet of sticky backed plastic you apply to the window covering the glass and normally goes up to just inside the frame edges. Even if it just covers the window, the only way to remove it, is to smash out the entire window around the frame, and the remains of the window glass will be left in one large window-sized piece. It also prevents people making a small hole and reaching through to unlock the window. It won't stop someone determined, but they will make a lot of noise getting through it.

If you need to replace the window, then you just remove the window from the frame and replace as normal. I would not suggest integrating it with the frame, but you might get away with applying it to glass before it is put into the window frame depending on type.

[Glazer]

As CIAS said it is best to put on the glass then put the glass into the frame. It does apply like window tint but is much thicker. And it's not cheap. If scratching is a problem you could have your windows reglazed with laminated glass like in the windshield of your car. But even that wont stop someone with enough determination.

BTW nice to see you back McNutty.

[Peeta Mellark]

Yes, it does work, having sat in an office and watching them bomb-proof windows with a variant of the stuff it is amazingly good at what it does. I don't think the shop bought one will be quite as good but the same principles apply.

I think it's probably as strong, but there's more of a chance of getting it wrong when you apply it. In our case, we had a big storm and a tree limb hit a window like a crowbar and that did manage to make it shift inwards on one edge. Now, was that because the stuff wasn't as good as the professionally applied stuff or because we made a mistake when applying it? It's hard to say, but having had to listen to my dad complain and say it was my fault, I'd prefer just hiring somebody next time.