How To Install Polycarbonate Roofing

Polycarbonate Roofing Installation

Professional DIY guide for timber-supported systems with step-by-step instructions

Why Choose Polycarbonate Roofing?

Superior Impact Resistance

200 times stronger than glass - providing exceptional safety and durability for your roofing project.

Easy Installation

Simple to cut and install, making it perfect for DIY projects and professional installations.

Long Life Expectancy

Designed to cope with both high and low temperatures, ensuring years of reliable performance.

Heat Protection

Solar sheets can reflect up to 85% of the sun's heat, preventing unwanted heat buildup.

Sheet Colour Options

Select the ideal colour for your project. Each option offers specific benefits:

Bronze/Opal

Mixed colours inside/outside

Solar Grey

Heat guard with silver tint

Selection Guide: Clear allows maximum light but no heat protection. Opal reduces heat buildup and hides dirt, requiring less cleaning. Bronze works well with timber structures like pergolas. Mixed sheets allow different colours on the inside and outside surfaces.

Roof Bar System Options

Timber Supported Snap Down Bars

Aluminium bottoms with plastic tops - excellent value for money and long-lasting when fitted correctly.

Gasket Roof Bars

Similar to snap-down bars but with gaskets and aluminium top caps. Suitable for any polycarbonate sheet or glass thickness.

Self-Supporting Bars

Independent glazing bars that don't require timber joists - ideal for specific applications.

Step-by-Step Installation

Step 1: Install Edge Bars

Fix your outside roof joists, then fix your first edge bar as shown in the diagram. Remove the rubber gasket from the bar and slide the edge fillet up the groove on the bar. Then, cut the bar to the required length. Line the bar so the edge trim is neat, then fix the bar to your joist. Mid bars need to be in the perfect position to ensure you are fitting them with the correct expansion gap, and they are straight. It is best to use a sheet of polycarbonate as a spacer.

Key Measurements:

Allow for 50mm overhang into the guttering
Cut the aluminium base 5mm longer than the intended polycarbonate sheet length
This allows the end cap to be fitted later

Drill and fix the bar into position with screws at 300-400mm centres screws only go in the centre of the roof bar. Ensure the drip on the edge trim is positioned correctly and neat from the external view. Repeat on the opposite end.

Timber supported roof bar system instructions

Wall Installation Tip: Where bars are butting against the wall, the edge trim is not required - fit the bar only.

Step 2: Plan Sheet Layout and Install Centre Bars

You have several options for sheet layout:

Cut all sheets to space them out evenly
Work towards a cut sheet in the middle
Use full-width sheets from the middle and add two cut sheets to the outer sides.

Important: Only cut the width on the last sheets when all other sheets are fitted.

Once you have decided on your layout, start fixing the centre bars in your required positions. Drill and fix the bars with screws at 300-400mm centres.

Pre-Installation Note: Measure each sheet before the roof joist is fixed, as roof sheets may vary in size by ±5mm.

CRITICAL: LEAVE A 4MM EXPANSION GAP BETWEEN BAR AND SHEET ON BOTH SIDES

Polycarbonate sheets fixed with roof bar

Step 3: Check Gasket Positioning

Ensure all rubber gaskets in the bars are flat with no bumps. This is crucial for proper sealing and placement of the sheet.

Step 4: Prepare Polycarbonate Sheets

Cut your polycarbonate sheets to length if they have not already been done, ensuring that all swarf (cutting debris) is removed.

Cleaning Method: Use a vacuum or condensation-free air to remove swarf. Never try to wash it out, as this can cause problems.

Anti-Dust Tape Application:

Use solid foil tape on the top of the sheet
Use vented tape on the bottom of the sheet
Peel the backing tape and stick it in place

Why Anti-Dust Tapes? These tapes reduce condensation and keep out insects and dust, so ensure they are fitted correctly.

Now peel about 50mm of the protective film down both sides and place the sheet on top of the two aluminium roof bars.

Step 5: Install PVCU Caps

Position PVCU caps so that the toothed legs are located inside the centre of the aluminium base. Press down firmly, then lightly hammer down with a rubber mallet or equivalent until the caps lock into place.

As you work across the roof, complete the flashing as you go. Remove the protective covering when the flashing is complete and all caps are in place.

Step 6: Final Installation

Fit the end caps into place. Cut sheet closures to the length between bars and push them in place as shown.

Optional Sealing: If desired, you can apply a bead of silicone along the top edge of the sheet closure for added weatherproofing.

Critical Installation Tips

What's Most Important?

Sheet Sizing: Sheets may vary in size, so have your roof sheets on-site before fixing the roof joists
Bar Calculation: Number of bars = number of sheets + 1. Example: 4 sheets need 5 bars
Long Projections: For roof projections over 4.0m long, use sheets 700mm wide or less
Expansion Gaps: Always maintain 4mm expansion gaps between bars and sheets
Proper Spacing: Use 300-400mm screw centres for secure fixing
Clean Installation: Remove all swarf and use proper anti-dust tapes

Need Professional Help?

Not sure about your Installation? Call us 01179 719922

Installation Complete!

Following these step-by-step instructions ensures your polycarbonate roofing provides excellent weather protection and long-lasting performance. Remember the three key principles: proper expansion gaps, secure fixings, and correct seal positioning.