Shed Window Glass: What to Use and Why It Matters

That Football Missed the Goal - and Hit the Shed

A customer in Kent rang me recently with a familiar problem: a piece of shed window glass had shattered—again. The original 3mm horticultural glass had been replaced after the first break with some thin styrene bought from a DIY chain. Cheap, easy, and available-but within a year, it had yellowed, cracked, and started to fall apart. Now they wanted a solution that would actually last. That story isn't unusual. But it always raises the question:

What's the right shed window glass for the job?

If you're reading this, chances are you're dealing with a broken pane-or about to start a shed upgrade. Maybe you're adding a window to let in more light. Maybe a child's football did the damage. Whatever the case, you're in the right place.

What is the best material for shed windows?

It's easy to assume that glass is glass. But shed window glazing is its own thing. Unlike your house windows, most sheds aren't built to the same standards. They shift slightly, flex in the sun, and face a different kind of wear and tear.

So when it comes to choosing shed window glass (or Perspex/ acrylic), it's not just about cost-it's about what performs best in the conditions. Not all of the options are created equal, so I have created a short guide below on the various choices for re-glazing your shed.

Horticultural Glass

This is what most sheds came with for decades. It's easy to find and gives that traditional garden look. But it's not safety glass-and when it breaks, it leaves sharp shards. It can also crack if your shed moves slightly with age or weather.

Great for: Budget replacements where there's little risk of impact.
Shed window Acrylic (Perspex)

Acrylic and Perspex are essentially the same material. Perspex is a brand name for a premium quality version of the material but the two materials are essentially interchangeable.

Acrylic is the sweet spot for most DIY shed owners. It's tougher than glass, won't shatter, and holds up well against stray balls or accidental knocks. Unlike styrene, it doesn't yellow quickly in sunlight. It scratches more easily than glass but is more resistant to scratches than polycarbonate.And best of all, it's light and easy to cut to size.

Great for: Family gardens, busy backyards, or sheds near play areas.
Polycarbonate

Polycarbonate is almost bulletproof (it is used for visors on motorcycle helmets), and it's practically impossible to break with casual force. But it's a bit overkill for most sheds unless security is a concern. It's also more expensive, it scratches more easilyand clarity can be slightly lower than acrylic.

Great for: Security sheds or exposed, rural locations.
Styrene (PETG)

You'll find this in a lot of budget shed kits and in the big box stores. It's cheap and light. But it scratches, discolours, and goes brittle quickly. You get what you pay for-and that usually means replacing it again next year.

Great for: Temporary use or very low-cost sheds.
Double Glazed Units

You can fit double glazing in a shed-but that doesn't mean you should. They're heavy, need a solid frame, and must be made to the exact size and depth for your window. Ideal for garden rooms or studios-but not practical for your average tool shed.

Great for: Insulated garden rooms or log cabins.
Toughened (Safety) Glass

When it breaks, it crumbles into harmless chunks-just like in your car windows. But it's custom-made and comes with a lead time. If you want it, you'll need accurate measurements and some patience.

Great for: High-end custom sheds, especially where visibility and safety matter.
Obscure or Frosted Film

Not a material, but a useful add-on. If you're storing valuable tools, this stops people peeking inside. It works with any glazing, and it's a simple DIY job to apply.

Great for: Tool sheds in overlooked gardens.

Some Common Questions About Shed Window Glass

What thickness of perspex should I use for my shed window?
Many shed window supplier will recommend 3mm acrylic, which is fine. On occasions when I have used 4mm acrylic, customers have often commented how much more solid the window is. The extra 1mm thickness is easily accommodated by most window frames. The thicker material is slightly more expensive, but if the slightly higher cost isn't an issue I would recommend you go for the 4mm thicknes.
Can you put double glazing in a shed?

Double glazing can be used in a shed. However you will need to have window frames built for the purpose. Double glazed units are heavier than a single pane of glass as there are two sheets of glass. Also the frame will need to be deeper to accommodate the two thicknesses of glass, plus the void between the two.

Double glazing will help to reduce overall heat loss from a shed, but it should be done in parallel with reducing draughts and potentially insulating the shed as well.

Is glass or perspex better for a shed?

I prefer using perspex/acrylic for shed windows. Acrylic is much easier to cut to size than glass. A glazier who cuts glass all day everyday may disagree. But I find that cutting acrylic by using a circular saw or scoring it several times along a marked line gives very reliable results.

Also when fixing acrylic you are much less likely to break it if you accidently clip it with a nail or knock it with a tool

So, for me it is acryllic every time!

Why Shed Window Acrylic is the Smart Choice (Especially in Kent)

If you're not ready to wait three weeks for a glass unit... if your kids like football... if your shed is more workhorse than showroom... then acrylic makes a lot of sense.

It's the option I recommend most often. And soon, I'll be stocking acrylic glazing sheets for DIY replacements.

Until then, if you live in Kent, feel free to contact me for help measuring, fitting, or supplying the right panel.

That Broken Window? It Won't Be the Last-Unless You Choose Well

Let's loop back. The football wasn't the real problem. The material choice was. Cheap styrene bought off the shelf was never going to last.

When you think about shed window glazing, think bigger than 'what fits in the hole.' Think about what fits your needs-for security, durability, and peace of mind.

And when you're ready to stop replacing the same pane every year? Think acrylic. I do.

Local Help If You Need It

I repair and replace shed windows within 20 miles of Tunbridge Wells-including Sevenoaks, Tonbridge, Crowborough, Cranbrook, and beyond.

Need a new pane? Not sure what size to order? Want to upgrade from brittle glass to something tougher? Get in touch-I'll either guide you through or quote for a visit.

Now you have chosen your shed window glazing material find out How to install shed window glass