How to Choose the Best Polycarbonate Roofing for Your Pergola

Choosing the right pergola roofing system depends on your existing structure, preferred appearance, budget, local climate and the level of weather protection you need.

Based on Excelite many years of experience supplying and building pergola roofs across Australia, here is a practical guide to help you compare the available options.

Quick Pergola Roofing Comparison

1. Do You Already Have a Pergola Frame?

Whenever possible, choose your pergola roofing system before building the frame. This allows the rafters or battens to be positioned correctly for the selected sheet width and roofing system.

If the pergola frame has already been constructed, check the roof pitch and support spacing before ordering your polycarbonate sheets.

Minimum Roof Pitch

We recommend a minimum roof pitch of 5 degrees for all pergola roofing systems. An adequate slope helps rainwater drain efficiently and reduces the risk of water pooling, dirt accumulation and leakage.

If your pergola is currently flat, appropriately designed packers or shims may be used to create the required fall. The supporting structure should be assessed before making any modifications.

Rafters: Check the Spacing Carefully

The widths of our solid polycarbonate locking system and multiwall locking system panels cannot simply be trimmed to match irregular rafter spacing. You need to build to suit, 600mm and 800mm centre-to-centre rafter distance recommended.

If the rafters already there, and can't be adjusted, Excelite flat polycarbonate roofing sheets can be cut to the required width and length, making them a practical option for existing pergolas with non-standard framing.

2. What Style of Pergola Roof Do You Prefer?

For a Clear, Glass-Like Pergola Roof

If you want maximum natural light and the appearance of glass, consider clear sheet in:

• Excelite solid polycarbonate locking panels; or
• Clear flat polycarbonate roofing sheets with aluminium glazing bars.

These systems provide excellent clarity while offering the lightweight construction and impact resistance of polycarbonate.

A minimum 5-degree roof pitch is still required.

For flat polycarbonate sheets, support spacing will generally depend on the sheet thickness, wind exposure and roof design. As a general guide, supports are commonly positioned approximately 500–800mm apart to help prevent excessive deflection or sagging.

If the existing spacing is too wide, additional rafters or cross-supports may be required.

For Better Heat Insulation

If insulation is more important than glass-like clarity, choose a multiwall polycarbonate roofing system.

The internal air chambers provide better thermal performance than a single solid sheet while still allowing natural light into the covered area.

For projects requiring a wider support span, a 16mm multiwall system may be able to span up to approximately 1,040mm in suitable applications. Final support spacing must always consider the specific product, sheet length, wind conditions and structural requirements of the project.

3. Are You Working With a Limited Budget?

If keeping the initial material cost low is the main priority, corrugated or twin-wall polycarbonate sheets may be suitable.

Option 1: Corrugated Polycarbonate Sheets

Corrugated sheets are generally one of the most economical pergola roofing options. They require relatively few accessories beyond the appropriate roofing screws, washers, flashings and closures.

Material prices may start from approximately $10 per linear metre, depending on the sheet profile, width, length and colour.

Option 2: Twin-Wall Polycarbonate Sheets

Twin-wall sheets provide improved insulation compared with basic corrugated roofing while remaining relatively affordable.

Indicative sheet prices may range from approximately $20–$30 per square metre, depending on thickness, colour and order quantity.

These prices are general guides only and may change. Contact Excelite for a current project-specific quotation.

4. Do You Need a Highly Leak-Resistant Pergola Roof?

For outdoor kitchens, furniture, electronics or other areas where dependable weather protection is particularly important, we recommend an Excelite polycarbonate locking system.

Both the solid and multiwall locking systems use a standing-seam design. The sheets are secured without driving screws through the polycarbonate panels.

Avoiding penetrations through the sheets offers several advantages:

• Fewer potential leakage points;
• Reduced risk of cracking around screw holes;
• Better accommodation of thermal expansion and contraction; and
• A cleaner, more professional appearance.

Our glazing bars also incorporate rubber seals to create a secure, weather-resistant connection.

When installed correctly and in accordance with the system requirements, selected Excelite locking systems may be covered by a ten-year waterproof warranty. Please contact us for the applicable warranty terms and installation conditions.

5. Is Your Property in a Coastal or High-Wind Area?

For coastal and high-wind locations, the solid polycarbonate locking system is generally the preferred option.

Selected configurations may be rated for wind speeds of up to 135mph—approximately 217km/h. However, suitability depends on the complete system configuration, fixings, supporting structure, building height and site-specific wind classification.

Projects in high-wind areas should be assessed against the relevant engineering and local building requirements before installation.

6. Do You Want More Light or Better Heat Control?

Your preferred level of light transmission and thermal comfort will help determine the most suitable sheet type and colour.

Choose Solid Clear Polycarbonate If You Want:

• A glass-like appearance;
• High natural-light transmission up to 92% LT;
• Clear views of the sky
• A modern, open feeling.

Choose Multiwall Polycarbonate If You Want:

• Better thermal insulation;
• Softer, diffused natural light;
• Reduced glare; and
• Greater privacy.

Clear, opal and tinted options are available across selected Excelite roofing ranges. Opal or tinted sheets may be more comfortable for pergolas that receive strong afternoon sun.

Can You Install Polycarbonate Pergola Roofing Yourself?

Some experienced homeowners and pergola builders can install polycarbonate roofing themselves.

Locking systems are designed to simplify installation and avoid screws penetrating the sheets. Flat sheets with separate aluminium glazing bars require more careful measuring, alignment and allowance for thermal expansion, so there may be more opportunity for installation errors.

If you are unsure about the structure, roof pitch, sheet spacing or flashing details, contact Excelite to discuss professional installation options.

Frequently Asked Questions

What is the minimum slope for a polycarbonate pergola roof?

Excelite recommends a minimum 5-degree roof pitch to support effective drainage and reduce water pooling.

Can polycarbonate roofing be installed on an existing pergola?

Yes, provided the existing frame has an appropriate roof pitch and suitable support spacing. Battens or additional rafters may be required for some locking systems.

Which pergola roofing looks most like glass?

Clear solid polycarbonate locking panels and clear flat polycarbonate sheets provide the closest glass-like appearance.

Which polycarbonate roofing offers better insulation?

Multiwall polycarbonate generally provides better insulation because its internal air chambers help reduce heat transfer.

What is the most affordable polycarbonate roofing option?

Corrugated polycarbonate is usually the lowest-cost option, followed by twin-wall polycarbonate sheets.

Which pergola roofing system provides the best protection against leaks?

A properly installed standing-seam locking system provides excellent leak resistance because screws do not penetrate the polycarbonate panels.

Find the Right Pergola Roofing System

The best pergola roofing material is the one that suits your structure, climate, budget and preferred appearance.

Before ordering, consider:

• Whether your frame uses rafters or battens;
• The distance between supports;
• The minimum 5-degree roof pitch;
• Local wind and coastal conditions;
• Desired light transmission and insulation; and
• Whether the roof will protect valuable furniture, electronics or an outdoor kitchen.

Excelite can help you select a suitable solid, multiwall, corrugated or flat polycarbonate roofing system for your project.

Visit www.exceliteplas.com.au or contact us for product advice, a quotation, or installation information.