Laminated Glass vs Tempered Glass

What is the difference between laminate glass and tempered glass? Well, today we’re going to stack them up head to head to show the differences between the two and how to decide which one is better for your needs. So, let’s jump in on our laminated glass vs tempered glass match up!

What is Safety Glazing?

Safety glazing is essentially any glass that provides protection against injury. There is a standard that defines what qualifies as safety glazing and that is ANSI Standard 97.1‑1972 go give it a read if you want to fall asleep quickly. There are areas where it is required by the building codes to keep you, well…safe. Bathrooms, doors, oversized windows and a few other situations all require safety glazing.

Laminated glass and tempered glass are the two main options when it comes to installing safety glazing in your house. Each works in very different ways to provide both injury protection and increased security over regular glass and I’ll show you how these work below.

What is Laminated Glass?

Laminated glass is exactly what its name suggests. It is two pieces of glass laminated together. There are many versions of laminated glass to accomplish different objectives from simple security and safety to ballistic and bomb proof glass.

In its simplest form, laminated glass is two pieces of 1/8” annealed glass glued together with a thin piece of PVB (plastic) sandwiched between them. Thicker glass and more layers of plastic can make the glass more and more secure. 

This three piece structure qualifies as safety glazing because when the glass is broken the plastic prevents the glass shards from breaking apart and keeps everything securely glued together. This also makes it extremely difficult to gain entry through laminated glass providing extra security against break-ins.

This laminated structure has one other major benefit which is sound blocking. Laminated glass is extremely good at blocking sound transmission which is a major benefit if you live in a noisy area.

How Can You Tell if You Have Laminated Glass?

Looking at laminated glass head on it’s almost impossible to tell the difference. It looks just like regular single-pane glass. There are two ways to determine the difference. First, if you can look at the side of the glass (a cross-section) you’ll see the layers of glass and know that you’ve indeed got laminated glass.

Second, laminated glass sounds different when you tap on it. Due to the plastic inter-layer laminated glass gives a dull thud when tapped compared to regular glass which gives more of a clear ting. Laminated glass can be cut to different sizes but it is a more tedious process than regular glass that I’ve outlined in this previous post.

Don’t confuse laminate glass with double-pane glass. There is no air space between the panes of laminated glass. No seals to fail or chance of fogging glass failure.

What is Tempered Glass?

Tempered glass is glass that has been heated to provide extra strength against breaking and, when it does break, it shatters into tiny pieces that are less likely to cause serious injury. Manufacturing tempered glass involves taking it through a furnace that heats it well above its transition temperature to around 1,148 °F. The glass is then rapidly cooled with forced air drafts while the inner portion remains free to flow for a short time.

Tempered glass is about four times stronger than regular annealed glass which makes it a great choice for safety glazing since it is far less likely to break and also less likely to injury you when it does break.

Tempered glass does not provide additional security like laminated glass, but it does provide increased protection against breakage. One important feature of tempered glass is that it cannot be cut. If you attempt to cut it will shatter.

How Can You Tell if You Have Tempered Glass?

You can’t tell by looking at it if you have tempered glass. It is indistinguishable from regular glass. Because of this most building codes require a small etched label in a corner of the glass to identify tempered glass. Other than that etched label there really isn’t another way to determine if the glass is tempered.

Laminated Glass vs Tempered Glass

So, now you know what each of these types of glass are, but how should you decide when to use one or the other? Both can be used interchangeably in most cases and the building codes rarely espouse a preference of one type over the other, but I can give you a few rules of thumb that I use as a window restorer.

When to Use Laminated Glass

• Security concerns are paramount
• Cost is not a big issue
• Noise is a concern
• Small panes of glass

When to Use Tempered Glass

• Security concerns are secondary
• More economical
• Low profile applications where thick glass won’t fit

Let me elaborate on some the things in my lists above. First laminate glass is more expensive than tempered glass. Sometimes as much as three times as expensive due to the labor intensive manufacturing process. Price is always a concern so keep that in mind as you decide which glass is right for you.

Also, tempered glass doesn’t provide any of the security or sound blocking qualities that laminated glass does. Maybe that doesn’t matter in your situation, and if that is the case then why spend more when you don’t have to.

Tempered glass has some size restrictions since it must first be cut to size and then tempered. Typically any piece that is smaller than 16” across measured diagonally cannot be tempered because it can’t be run through the rollers on commercial glass ovens. In cases where you need very small panes of glass, laminated may be your only option.

Finally, laminated glass has a minimum thickness of about 1/4” since you are combining two pieces of glass. There may be some applications where you can’t fit a 1/4” thick piece of glass. If you need thinner glass than 1/4” then tempered glass will likely be your only option since it can be made from almost any thickness of glass.

Hopefully, this post has helped you understand the differences between these two forms of safety glazing and you can make a better decision when you’re faced with the question of laminated glass vs tempered glass in the future.