16mm Polycarbonate Sheets – Strong, Insulated Roofing for Pergolas, Lean-Tos and Outdoor Structures

16mm polycarbonate is one of the most popular roofing options for outdoor structures because it offers an excellent balance of strength, insulation, light transmission and noise reduction. It is ideal for pergolas, lean-to roofs, verandas, carports, garden rooms and covered seating areas.

Compared to 10mm, 16mm provides noticeably more rigidity, improved thermal performance and a quieter experience in rain. It is suitable for most small and medium-sized roofing projects in typical UK conditions.

Best Uses for 16mm Polycarbonate

16mm is suitable for:

• Pergola roofs

• Lean-to roofs attached to the house

• Verandas and patio canopies

• Carports and shelters

• Garden rooms and outdoor seating areas

• Walkways and covered areas

• Roofing where insulation or noise reduction matters

16mm is not recommended for:

• Conservatories needing high insulation (25mm is better)

• Greenhouses (thinner sheets allow more light)

• Very large spans without support

• Projects requiring high structural strength over long gaps

Why Choose 16mm Polycarbonate

• Stronger and more rigid than 10mm, suitable for most outdoor roofing projects.

• Provides better insulation and noise reduction during rainfall.

• Available in clear, opal and bronze for different lighting and privacy needs.

• Still lightweight and easy to handle compared to glass or solid sheets.

• UV-protected outer layer to prevent yellowing.

• Reliable performance in typical UK weather conditions.

• Excellent all-round solution for DIY users and trade professionals.

Available Options

Your 16mm range may include:

• Clear, Opal and Bronze multiwall sheets

• Lengths such as 2m, 2.5m, 3m, 4m, 5m or 6m

• Standard multiwall sheet widths

• Aluminium or PVC glazing bars

• End caps, closure caps and breather tape

• Roof-specific fixings

Installation Advice

To install 16mm polycarbonate correctly:

• Use appropriate glazing bars for full support and weatherproofing.

• Tape and cap the open ends of the sheet before installation.

• Allow room for thermal expansion to prevent warping.

• Ensure the UV-protected side faces outward.

• Follow manufacturer span recommendations to prevent sagging on larger projects.

• Use suitable fixings and avoid overtightening.

Common Mistakes to Avoid

• Using 16mm without glazing bars, which leads to leaks or sheet movement.

• Overtightening screws and restricting expansion.

• Leaving open ends unsealed, allowing moisture or debris into the chambers.

• Attempting very long unsupported spans where a thicker sheet or more rafters are required.

• Choosing the wrong colour for the project (e.g., clear in a south-facing area may lead to too much glare).

Choosing a Better Thickness if Needed

If your project needs greater insulation or structural performance, consider:

• 25mm for conservatories, high insulation, and maximum noise reduction.

• 10mm for budget projects or smaller structures.

• 6mm for glazing-only applications such as greenhouses.

Why Buy from PolycarbonateX

• UK specialist supplier with dedicated product knowledge.

• Fast, protective delivery for multiwall roofing sheets.

• Free replacement if any sheets arrive damaged.

• Clear installation guides supporting DIY and trade users.

• Friendly support available for project advice by phone or email.

Need Help Choosing?

If you are unsure whether 16mm is right for your structure:

• Use the thickness selector on the category page.

• Contact us for guidance.

• Send a photo of your project for personalised recommendations.