25mm polycarbonate sheet

25mm Polycarbonate Roofing Sheets

Our 25mm polycarbonate roofing sheets are designed for projects where insulation, thermal performance and long-term comfort are the highest priorities. As the thickest option within our standard multiwall roofing range, 25mm polycarbonate is ideal for conservatories, garden rooms, insulated lean-to roofs, premium verandas and year-round outdoor living spaces.

Available in Clear, Bronze, Opal, Heatguard Opal and Bronze Opal finishes, our 25mm roofing sheets provide exceptional rigidity, improved weather protection and excellent noise reduction during rainfall. They are a popular choice for homeowners and trade professionals looking to create warm, comfortable and durable outdoor structures.

For projects requiring bespoke dimensions, we also offer a dedicated 25mm Cut To Size Polycarbonate Sheet service, allowing you to order sheets manufactured to your exact measurements.

Best Uses for 25mm Polycarbonate

25mm is suitable for:

• Conservatory roofing

• Garden rooms and insulated outdoor spaces

• Lean-to roofs where warmth and noise reduction matter

• Verandas and premium patio covers

• Covered walkways and commercial shelters

• Roofs in more exposed or wind-prone areas

• Any project requiring good insulation

25mm is not recommended for:

• Greenhouses (thinner sheets provide better light transmission)

• Lightweight or temporary structures

• Projects where maximum natural light is needed

• Applications where a slim or minimal profile is preferred

Why Choose 25mm Polycarbonate

• Offers the highest insulation value among standard multiwall sheets.

• Strong, rigid and suitable for larger spans when supported correctly.

• Significantly quieter in rainfall than thinner sheets.

• Ideal for creating warm, liveable outdoor or semi-indoor spaces.

• Available in clear, opal and bronze depending on lighting and privacy needs.

• UV-protected to resist yellowing and maintain clarity.

• Reliable performance in challenging UK weather conditions.

Available Options

Your 25mm range may include:

• Clear, Opal and Bronze multiwall sheets

• Lengths such as 3m, 4m, 5m and 6m

• Standard multiwall widths 

• Aluminium glazing bars designed for heavy-duty roofing

• Closure caps, tapes and structural fixings

Installation Advice

To install 25mm polycarbonate effectively:

• Use strong, suitable glazing bars to support the sheet’s weight and thickness.

• Seal all sheet ends with the correct tape and closure trim.

• Allow expansion gaps to prevent warping or buckling in warm weather.

• Always position the UV-protected side outward.

• Follow manufacturer recommendations for maximum spans and rafter spacing.

• Use appropriate fixings designed for thicker multiwall panels.

Common Mistakes to Avoid

• Using 25mm on a structure not designed to support thicker panels.

• Assuming all colours perform the same; opal offers better heat control than clear.

• Forgetting to seal open ends, leading to condensation inside the chambers.

• Using insufficient glazing bars, causing sagging over time.

• Choosing 25mm for greenhouses where maximum light is needed.

Compare Alternative Thicknesses

If your project requires a different balance of insulation, rigidity and light transmission, you may wish to consider one of our alternative polycarbonate sheet thicknesses.

16mm Polycarbonate Sheets

A popular all-round roofing option for pergolas, verandas, lean-to roofs and garden rooms where excellent insulation and strength are required.

10mm Polycarbonate Sheets

Ideal for carports, canopies, shelters and budget-friendly roofing projects where affordability and lightweight installation are priorities.

Need a Custom Size?

If your project requires bespoke dimensions, view our 25mm Cut To Size Polycarbonate Sheet service and order sheets manufactured to your exact measurements.

Why Buy from PolycarbonateX

• Dedicated UK supplier specialising in polycarbonate roofing.

• Fast delivery of large roofing sheets with protective packaging.

• Free replacement if any sheet arrives damaged.

• Clear installation guidance for DIY and professional users.

• Project support available by phone or email.

Need Help Choosing?

If you are unsure whether 25mm is right for your project:

• Use the thickness selector on the category page.

• Contact us for personalised advice.

• Send a photo of your structure for a tailored recommendation.

Not Sure Which Roofing Sheets You Need?

Choosing the right polycarbonate sheet depends on the type of project you're building. Whether you're installing a pergola, lean-to roof, veranda, carport, conservatory, garden room, canopy or covered walkway, our Roof Types guide will help you compare the best sheet thicknesses, colours and applications.

Explore our Polycarbonate Roof Types guide to find the right roofing solution for your project.