Installing polycarbonate sheets
- Place the first sheet of roofing onto the pergola, sliding it under the flashing. Make sure the roofing is parallel to the rafters, and that there’s a 60mm overhang at the end. Also, ensure that the end of the sheet that’s been cut is against the house.
- Once it’s in place screw the sheet onto the purlins of the pergola.
- Using 14g x 50mm guage polycarbonate fasteners will mean you don’t need to pre-drill any holes, and will drastically cut your installation time down.
- Fix the screws through every second high point on the roofing - this stops water leaking through the holes. Use a straight edge to mark your screw points, so they’re in a neat straight line. Don’t screw in the first high point, allowing for the overlap of the next sheet.
- Drill the screw down just enough so that it doesn’t push the sheet down too far.
- When drilling the holes through the flashing and polycarbonate roofing, use a standard roofing screw.
- Place the next sheet of roofing, ensuring there’s an overlap, and that it’s in line with the previous sheet.
- Drill through the overlap, and continue fixing the sheet as per the steps above.
- Renail your weatherboards, through the flashing, as you work your way along.
- Mould the soft edge of the flashing into the corrugated roofing.
- Continue laying the rest of your sheets. When you get to the end sheet, you may need to cut it to width – if this is the case, make sure the non-cut side is on the outside.