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Hi,
I'm looking to add polycarbonate roofing to my pergola and wanted to known if I should introduce a slope for water to drain off or if it should be fine to lay it flat on the existing roof.
attaching the existing timber roofing that already exists and it is flat with no slope in it.
Hello @jacobisaac
Thank you for sharing your question about polycarbonate installation. It is necessary to install a slope, several things could happen if a slope is not installed. Water will flow in every direction and travel to all sides of the polycarbonate which means that water could pool and flow towards your brick wall causing it to puddle on your patio.
Water could pool in the middle of your pergola and will cause lensing which will damage the polycarbonate. It can also cause mould to form on the surface. A moderate fall should be sufficient enough to give the water enough momentum to roll off the roof. Please make sure to use H3-treated timber when choosing your battens.
Here is a link to the Palram installation guide: Palram Installation
Here is a handy step-by-step guide: How to install battens on a carport roof
If you have any other questions we can help with, please let us know.
Eric
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