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How to Polycarbonate Roofing Installation?

Renowned for its versatile application in various industries like agriculture, construction, automotive, aviation, electronics and printing, polycarbonate is made by combining different thermoplastic polymers that have chemically structured groups. Due to its thermoplastic and transparent properties, polycarbonate is mainly used in construction industry as a skylight and exterior spaces like pergolas. For this reason, installation is quite easier compared to other roofing materials. This article gives a detailed step-by-step guide on installation of polycarbonate roofing.


Any successfully executed project heavily leans on preparation and planning invested into it. Polycarbonating your roof is no different; you have to plan adequately. Planning entails measuring the roof where you want to install the sheets. Exact measurements help you to purchase the right size and exact number of sheets to avoid wastage. Even if you might need additional sheets in the future, it is wiser to purchase them when the time comes, than having to stress over storage. This is because if not properly stored, polycarbonate sheets might be damaged, costing you significant losses.

Roofing installation done right!

During the planning stage, you will also determine what profile fits best for your roof framing. If you need more sturdiness, corrugated profile would be your option while flat profile is best for pergolas and deck roof.

Tools and Materials

Having decided the number and size of sheets you need for the job, you then proceed to your local supplies store to purchase the required tools and materials. When purchasing the sheets, ensure to follow the pre-taken measurements. Be sure to add one more sheet to cater for any breakage or unforeseen circumstances. For safety, you will need a pair of goggles, gloves, ladder and a safety harness if the section is high on the roof. Fasteners, screws, screw caps, jointer strips and a power drill are some of the items you will need to secure the sheets on the purlins. You will also need a measuring tape and tin snips for perfect sheet cuts.


With the right tools and materials at hand, you now embark on the installation. Pre-drill the screw holes into the already installed purlins on your roof. Pre-drilling helps in prevent cracking the sheets when fastening them in the subsequent steps of the process. When drilling, ensure the holes are a little bigger than the screws to allow room for thermal expansion. With the measurements taken in the previous stage of the process, use the saw and tin snips to cut the sheets to the clean and exact measurements. When cutting the sheets, ensure to leave allowances for overlapping and overhanging the edge of the roof. Overlapping ensures perfect fitting to keep rainwater out, while overhanging allows for water runoff, thereby protecting the sidings.

Positioning the Sheets

The next process step entails you laying the cut sheets over the framing. Start on one edge of the roof and work your way towards the other edge. As previously mentioned, ensure the sheets overhang the edge to allow room for water runoff. It is the only way to protect your walls from runoff damage. As you lay the other sheets towards the other end, ensure they overlap a little, by at least one ridge of the corrugation. Overlapping helps in achieving a tight layout to keep water out of your spaces. The UV protected side of the sheet should face upwards.

Securing the Sheets

Place the screws and sealing washers on the ridges if using the corrugated profile and fasten them using the power drill. When using the flat profile, place the screws evenly about 350mm apart. Whichever profile you are using, ensure the screws fall along the overlaps and purlins.

Installing Caps and Flashings

Install the end caps on the open ends of the polycarbonate roof to keep water ingress and insects off your living spaces. In the case of a ridge roof framing, install ridge caps along the ridge. These cover both sides of the roof and keep water ingress, debris and insects from invading your living spaces. Finish the job by installing flashing caps along the sides of the roof to keep water from entering between the sheets.

Finishing Touches

Check all screws, sealing caps and washers to ensure they are moderately tightened and clear all the debris from the roof.

Polycarbonates are thermal plastic, something that calls for room allowance. Extra care should also be observed when installing the sheets to avoid breakages since they are not as sturdy as iron sheets. If you are uncomfortable with high roofs, consider contracting the task to a professional for safety considerations and quality results.