Timber Supported Polycarbonate Roof Kit – 4.31m Coverage

Select the type and colour of polycarbonate required when ordering.

Our 4.31m Timber Supported Polycarbonate Roof Kit is a complete roofing solution for timber-framed canopies, lean-to roofs, porches, covered walkways and other outdoor structures. The kit includes the polycarbonate sheets and essential fixing and finishing components, making it easier to complete your roofing project without sourcing each part separately.

Supplied from Bristol, the kit is suitable for DIY projects, builders and professional installers.

What's Included

• 4 x 1050mm x 2.5m polycarbonate roof sheets
• 5 x 2.5m bars for fixing to timber
• 2 x 3m edge fillets
• 4 x 1050mm sheet closures
• 1 x 150mm flash band
• Anti-dust tapes

Actual roof coverage: approximately 4.31m.

Installation Guide

Step 1 – Fit the Edge Bars

Fix the first edge bar into position and slide the edge fillet into the groove. Cut the bar to length, allowing for a 50mm overhang into the guttering. Cut the aluminium base approximately 2mm longer than the polycarbonate sheet to allow for the end cap.

Secure the bar using No. 6 screws at approximately 300–400mm centres, ensuring the drip on the edge trim is correctly positioned. Repeat at the opposite edge.

Note: Where a bar butts against a wall, the edge fillet is not required; fit the bar only.

Step 2 – Position the Centre Bars

Position the remaining bars according to your chosen sheet layout and secure them to the timber using screws at approximately 300–400mm centres.

IMPORTANT: Leave a clear 4mm expansion gap between the bars and the polycarbonate sheets.

Step 3 – Check the Gaskets

Before fitting the sheets, check that all rubber gaskets are flat and correctly positioned, with no bumps or raised sections.

Step 4 – Prepare and Fit the Polycarbonate

Cut the polycarbonate sheets to length if required and remove all swarf using a vacuum or condensation-free air line. Never wash swarf out of the sheet channels.

Fit the anti-dust tapes correctly, using the solid foil tape at the top and the vented tape at the bottom. These tapes help reduce condensation and prevent insects and dust entering the sheet channels.

Peel approximately 50mm of protective film from both sides of the sheet and position the polycarbonate into the bars.

Step 5 – Fit the PVCU Caps

Position the PVCU caps so the toothed legs locate inside the aluminium base. Press down firmly and lightly tap into place with a rubber mallet until the caps lock securely.

Complete the flashing as you work across the roof. Once the caps and flashing are fitted, remove the remaining protective film.

Step 6 – Complete the Roof

Fit the end caps and cut the sheet closures to the required length between the bars. Push the closures securely into position.

Installation Tips

Polycarbonate cut to size: If you require sheets cut to size, we recommend fitting the bars first and then ordering the polycarbonate. We can cut, blow and tape the sheets to the required width and length. Remember to allow for thermal expansion. Price on application.

Lead flashing: If using lead flashing, fit it before the sheets and dress it down as the roof panels are installed. Fit lead in sections of approximately 2m and seal 100mm overlaps with Lead Mate.

Cleaning: Use mild soapy water only. Test a small area first and never use solvent-based cleaners.

Silicone: Silicone should not normally be required. If necessary, use a good-quality low-modulus neutral clear silicone.

Recommended sheet widths: For the best long-term performance, avoid excessively wide sheets. We recommend widths of approximately 980mm or less for roofs up to 4m long and 700mm wide for roofs over 4m long.

Timber structure: Fix wall plates at the top and bottom and install the joists as you fit the polycarbonate bars.

Finishing: For a low-maintenance finish, use 9mm economy fascia around the roof with square white guttering.

Polycarbonate Roofing Kits Bristol

We supply timber supported polycarbonate roofing kits from Bristol for DIY customers, builders and professional installers. This 4.31m kit provides the main components needed to create a secure and weather-resistant polycarbonate roof over a timber structure.

Not sure which polycarbonate or roofing kit you need? Contact us and we'll be happy to help.