Are Shower Doors Tempered Glass? (Answered)

We’ve just had new tempered glass shower doors fitted in our ensuite bathroom and guest bathroom. But are all shower doors tempered glass?

Shower doors have to be made from safety glass, and the most common type is tempered glass. This is four times more durable than regular glass and can withstand a minimum surface compression of 10,000 psi (pounds per square inch). If it shatters, it breaks into tiny pieces rather than sharp shards.

Let’s dive down into the subject of tempered glass shower doors in more detail, and answer all your most pressing questions about this essential piece of safety material in the bathroom…

Are All Shower Glass Doors Tempered?

Shower doors have to be made from safety glass, and the most common type is tempered glass.

This is about four times more durable than regular glass, and if it shatters, it breaks into tiny pieces rather than sharp shards.

How Do I Know if My Shower Door Is Tempered?

Tempered glass is made through a process of heating followed by rapid cooling. Because of this extra processing, the edges of the glass become smooth.

Gently run your finger down the edge of your shower door (if you can), and if it’s smooth, it’s likely to be tempered.

But what if the edge isn’t exposed? Do you have a pair of polarizing shades? Pop them on and look at your shower door.

You may be able to see the marks left by rollers, which are used during the tempering process. These will show up as darker or lines, and you may see some faint surface scratches.

And of course, you can also look for the bug symbol. This mark is the manufacturer’s indication that the glass has been tempered. Because this is typically on the edge of the glass panel, it may be obscured by the door frame – time to get those shades on…

Are Framed Shower Doors Tempered?

Yes, many framed shower doors are made from tempered glass, and the glass has to be slightly thinner to fit into the frame.

Frameless glass shower doors are more fashionable at the moment. However, a frame gives the door extra stability and makes it easier to install.

It also forms a good water-tight seal – although this does mean that they need more careful cleaning, as mildew and mold can form around the edges.

When it comes to glass safety, both types of shower door, framed and frameless, are likely to be made from tempered glass.

Do Shower Doors Have to Be Glass?

You don’t have to have a glass shower door. In fact, you don’t have to have a shower door at all.

A shower curtain is a cheaper and more colorful alternative, or you could choose to have a wet-room-style shower with no door at all.

However, if you decide to choose a framed or frameless glass shower door, it must be made from safety glass.

Because this has been in the building codes since the 1960s, you’re very unlikely to come across a door that’s made from any other type of glass.

There’s another alternative to tempered glass, and that’s glass with a layer of laminate on both surfaces.

Like normal tempered glass, this prevents the problem of glass shattering and breaking into dangerous shards. The glass is held tightly between the two sheets of laminate.

How Strong Are Tempered Glass Showers?

A tempered glass shower door is roughly four times tougher than an annealed glass equivalent.

If you like to get technical about it, a tempered glass door should be able to withstand a minimum surface compression of 10,000 psi (pounds per square inch).

This is more pressure that you need for a simple shower enclosure. However, you’re choosing it for its ability to break safely (shattering into small pieces rather than into sharp spikes) rather than for the fact that you can stand on it.

Do Shower Doors Shatter and/or Explode?

This is a rather startling fact, but yes, glass shower doors (and other glass surfaces) can suddenly shatter or “explode”, for no apparent reason.

Before you run off to replace your shower doors with a curtain, please remember that this is very, very rare.

However, it’s not impossible. What is this phenomenon? 

There are a couple of main causes of spontaneous shattering. One is due to the tempering process. There are nickel sulfide inclusions in the glass, which grow and cause stresses over time.

These can then break under heat, even years after the glass has been tempered – but this occurrence is really rare, and you’d be extraordinarily unlucky if this happened to you.

Some manufacturers choose to literally test their tempered glass to destruction. They carry out an extra process called “heat soaking”, which exposes the glass to higher levels of heat than nickel sulfide can deal with, within the safety of an enclosed chamber. 

If the glass is going to shatter because of nickel sulfide inclusions, it will do it now, rather than further down the line and in your bathroom. Because the risk is so slight, a lot of manufacturers don’t carry out this process.

If you’re interested in this process, take a look at this short film about destruction testing tempered glass. It shows the heat soak process, as well as explaining nickel sulfide inclusions in a bit more depth. In this case, it’s looking at huge sheets of architectural glass, but it’s the same procedure.

There is also a second potential issue with tempered glass, which again is not an everyday occurrence. Tempered glass is super-strong when it comes to a face-on impact.

However, it’s more resistant to an impact from the side, so a small chip at the edge can make the whole door shatter. This is another reason why framed doors can be a good idea because the frame protects these more vulnerable edges.

As well as these two issues that are inherent with tempered glass, shower doors can also shatter as a result of incorrect installation.

If the glass shower door hasn’t been properly fixed, it could slip off its fittings and shatter. That’s why it’s really important to have your shower installed by a reputable professional.

Can You Drill Through Tempered Glass?

No, you can’t drill through tempered glass, and no professional would even attempt this. Any cutting or shaping is done prior to the tempering process.

What does happen if you attempt to drill into tempered glass? Not good, unfortunately – it will shatter immediately. Any holes that are needed for things like door handles must be drilled before the glass goes through the tempering process.

So if you have a shower with glass doors and you want to add a new hook or a different size handle, it isn’t actually possible. Sorry.

Final Words: How Do You Clean Tempered Glass Shower Doors?

Tempered glass shower doors are easy to clean. Water spots are the enemy when it comes to keeping our showers looking sparklingly clean, and some quick and simple cleaning routines can prevent these from building up.

Keep a squeegee in or close to your shower, and after you’ve finished showering, give it a wipe down. Keeping the shower doors open after use will help to prevent mold or mildew from developing.

For a slightly deeper clean, you can spritz the glass with a homemade cleaning solution. A mix of lemon juice and distilled water will help to keep your glass shiny, or you can use our old cleaning friend, vinegar.

Before you clean your shower doors, however, check that your cleaning solution won’t damage the rest of the shower. You shouldn’t use vinegar on stone tiles, for example.

If you have shower doors with frames, use an old toothbrush to scrub regularly around the rim and edges. This prevents a build-up of soapy debris, and helps to stop mildew from developing in those hard-to-reach spots. 🙂