Tips when working with polycarbonate roofing

Updated: Jan 24


Polycarbonate is an ideal roofing material for a wide range of applications. It is surprisingly durable, resistant to heat and provides ample protection from the sun’s harmful UV rays. Here are a few tips to follow when installing polycarbonate roofing.
  • Read the manufacturer’s instructions and specifications. Then follow these to the letter. If you do not, your warranty will be voided by the manufacturer.

  • Install the polycarbonate sheets at a minimum pitch of 5 degrees (that is, This allows rainwater to run off toward the gutter and prevents moisture from collecting on your roof)

  • Temperature changes throughout the day will cause the roofing sheets to expand and contract, so you need to make allowances for this thermal movement. Otherwise, the resistance to these temperature adjustments will cause your roofing sheets to buckle.

  • When installing polycarbonate roofing, it is considered good practice to pre-drill the screw holes before fixing the sheets. It is also recommended that you slightly oversize these holes to make room for the thermal adjustments described above.

  • Caps and flashings should likewise be pre-drilled so that when installed, the roofing sheets underneath can also shift as the temperature changes.

  • You can use One Shot fixings, each of which comes with its own hole cutter. This can speed up your installation work because they eliminate the need for pre-drilling.

  • You must install the sheets with the UV-protected side facing the sun. Look for a sticker that tells which side is UV-protected. Also take care not to scratch the sheets during installation as this will damage the UV protection layer.

  • Also pay attention to the prevailing wind direction and make sure you lay down the sheets in the correct orientation. The last thing you want is for the wind to tear away your polycarbonate sheets.

  • Use purlin tape on all the surfaces that come in contact with the timber.

  • Don’t use sheets with purlin spacing wider than recommended. If you do, the sheets may sag and let water collect and pool in the sagging areas.

  • We do not recommend using silicone to cure polycarbonate roofing because polycarbonate sheets expand and contract much more widely than silicone. But if you have to use it, use only neutral cure silicone.

  • The polycarbonate sheets come with a list of the manufacturer’s recommended infills and back channels. Do not use bitumen-impregnated foam infills. These will damage the polycarbonate sheets!

  • If some sheets will end up overlapping a gutter, drill a 1/4in hole into the pan 1/2in from the edge of the sheet. This will provide a drip-off point.

We hope you find these tips helpful as you prepare to install polycarbonate roofing over your patio deck or pergola. For more polycarbonate roofing tips and ideas, check out some of our other blog posts. Buy Polycarbonate Roofing Online.

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