Multiwall Polycarbonate Roofing Sheets

Whether you're building a pergola, replacing a carport roof or planning a brand-new garden room, choosing the right roofing material is one of the most important decisions you'll make. Multiwall polycarbonate roofing sheets have become one of the UK's most popular roofing solutions because they combine excellent strength, low weight and outstanding durability while allowing natural daylight to pass through.

At PolycarbonateX, we specialise exclusively in polycarbonate roofing systems. Our range of multiwall polycarbonate sheets has been carefully selected to suit everything from small DIY glazing projects through to large outdoor living spaces and commercial roofing applications. Combined with our glazing bars, flashings, fixing systems and installation accessories, they provide everything needed to build a professional-quality roof.

Whether you're an experienced installer or taking on your first roofing project, we'll help you choose the right sheet thickness, colour and accessories for your application.

What Are Multiwall Polycarbonate Sheets?

Unlike solid plastic sheets or traditional glass, multiwall polycarbonate contains a series of internal chambers, often referred to as flutes. These chambers create an exceptionally strong yet lightweight sheet while also improving thermal performance compared with single-layer glazing materials.

The result is a roofing material that offers an excellent balance between strength, insulation and light transmission.

Because polycarbonate weighs considerably less than glass, it's much easier to transport, lift and install. At the same time, it's extremely impact resistant, making it a safer and more durable option for outdoor roofing.

This combination of performance and practicality explains why multiwall polycarbonate has become the material of choice for pergolas, verandas, canopies, carports and many other outdoor structures throughout the UK.

Why Choose Polycarbonate Instead of Glass?

Many customers begin their search assuming glass is the obvious choice, particularly if they're replacing an older roof.

In reality, modern multiwall polycarbonate offers several significant advantages.

First, it's considerably lighter than glass, making installation much easier and reducing the load placed on the supporting structure.

Secondly, it's exceptionally impact resistant. Unlike glass, which can crack or shatter if struck, polycarbonate is designed to withstand everyday knocks, hail and adverse weather conditions.

The internal multiwall construction also provides improved thermal performance compared with single-pane glass, helping to create a more comfortable outdoor environment throughout the year.

For most modern outdoor roofing projects, these advantages make multiwall polycarbonate the preferred solution.

Which Thickness Should You Choose?

One of the questions we're asked most often is:

"What thickness polycarbonate do I need?"

The answer depends entirely on the type of project you're building.

4mm & 6mm

These thinner sheets are primarily intended for greenhouse glazing, cold frames and lightweight DIY projects. They provide excellent light transmission while remaining easy to cut and install.

10mm

10mm is where polycarbonate becomes a true roofing material. It's an excellent choice for carports, canopies, porch roofs and smaller covered areas where strength and value are equally important.

16mm

If someone asks us to recommend a single sheet for most domestic roofing projects, it's almost always 16mm.

It offers an excellent balance between rigidity, insulation, weather resistance and price, making it ideal for pergolas, verandas, lean-to roofs and outdoor living spaces.

25mm

For conservatories, garden rooms and premium outdoor spaces where insulation is especially important, 25mm provides the highest thermal performance in our range.

Choosing the Right Colour

The colour you choose can dramatically change the finished appearance and comfort of your roof.

Clear remains the most popular option, allowing the maximum amount of natural daylight into the space.

Bronze helps reduce glare and solar heat gain, making it an excellent choice for south-facing gardens or areas exposed to strong sunlight.

Opal softens incoming daylight to create a brighter, more comfortable environment while also providing additional privacy.

For projects where heat reduction is particularly important, specialist solar-control options are also available.

If you're unsure which colour best suits your project, we're always happy to offer advice.

Popular Applications

Multiwall polycarbonate roofing sheets are used in a huge variety of projects, including:

• Pergolas

• Verandas

• Lean-to roofs

• Carports

• Canopies

• Garden rooms

• Conservatories

• Covered walkways

• Patio covers

• Outdoor seating areas

• Commercial shelters

The versatility of multiwall polycarbonate is one of the main reasons it has become so widely used throughout the UK.

Installing Multiwall Polycarbonate Sheets

Correct installation is just as important as choosing the right sheet thickness.

All sheets should be installed with the UV-protected face facing upwards and sufficient clearance should always be allowed for thermal expansion.

Before fitting, the open flutes should be sealed correctly using aluminium foil tape on the upper edge and breather tape on the lower edge. Aluminium end closures should then be fitted to protect the tapes and provide a neat finish.

For rafter-supported roofs, compatible glazing bars and side flashings complete the installation while helping create a weather-resistant roofing system.

Although installation is straightforward, taking the time to use the correct accessories will greatly improve the appearance and longevity of the finished roof.

Complete Your Roofing System

A high-quality roof depends on more than just the sheets themselves.

At PolycarbonateX we also supply:

• PVC Top Cap & Aluminium Base Glazing Bars

• Polycarbonate Sheet End Closures

• Polycarbonate Sheet Sealing Tape Kits

• Side Flashings

• Wall Flashing Tape

• Polycarbonate Sheet Fixing Buttons

All have been selected to work together as part of the PolycarbonateX Roofing System, helping you achieve a professional-quality installation.

Why Buy from PolycarbonateX?

Polycarbonate roofing isn't just one of our product categories—it's our speciality.

Every product in our range has been chosen to work as part of a complete roofing system, giving you confidence that your sheets, glazing bars and accessories are fully compatible.

When you choose PolycarbonateX you'll benefit from:

• High-quality multiwall polycarbonate roofing sheets.

• Carefully matched roofing accessories.

• Friendly expert advice before and after your purchase.

• Secure packaging to protect your order in transit.

• Fast UK delivery.

• Comprehensive installation guides and technical support.

Whether you're replacing a few greenhouse panels or creating an entirely new outdoor living space, our team is here to help you choose the right products first time.

Frequently Asked Questions

Are multiwall polycarbonate sheets suitable for use in the UK?

Yes. Our sheets are manufactured with a UV-protected outer surface and are specifically designed for long-term outdoor use in the UK's changing weather conditions.

Which thickness is best for a pergola?

For most pergolas, we recommend 16mm multiwall polycarbonate. It offers an excellent balance of strength, insulation and value for money, making it our most popular choice for domestic roofing projects.

Can I cut polycarbonate sheets myself?

Yes. Multiwall polycarbonate can be cut using suitable DIY tools. Always support the sheet correctly and follow the recommended installation guidance.

Do I need glazing bars?

Yes. Most rafter-supported roofing projects require glazing bars to securely support and join the sheets while allowing for natural thermal expansion.

Do I need breather tape?

Yes. Correctly sealing the open flutes is an important part of any installation. Aluminium foil tape is fitted to the upper end of the sheet, while breather tape is fitted to the lower end before installing the end closures.