Correct installation is critical to the service life, waterproof effect, and appearance of polycarbonate roofing sheets. Many quality problems such as water leakage, cracking, and yellowing are caused by improper installation. This article provides a complete professional guide for Southeast Asian users.
Step 1: Confirm the UV side
The protective film of the PC sheet is marked with “UV OUT” or “This side out”. This side must face outward to ensure UV resistance. Installing it upside down will cause rapid yellowing and aging.
Step 2: Reserve expansion gaps
Polycarbonate has a thermal expansion coefficient of 0.065 mm/m/°C. In the high-temperature climate of Southeast Asia, the sheet expands significantly. An expansion gap of 2–3mm per meter must be reserved, and 5–8mm at the ends. Otherwise, the sheet will bulge and crack.
Step 3: Drilling requirements
The drill hole diameter should be 20%–30% larger than the screw diameter to allow for thermal expansion. Use a sharp drill bit and low speed to avoid chipping. Support the sheet from below during drilling to prevent bending.
Step 4: Use special screws and gaskets
Stainless steel screws with EPDM waterproof gaskets must be used. Do not use ordinary iron screws or over-tighten, as this will cause stress cracking.
Step 5: Fixing with profiles
Aluminum alloy or UPVC special profiles should be used for pressing and fixing. Matching rubber sealing strips ensure waterproof performance. Do not directly fix the sheet with angle steel or wood.
Step 6: Sealing treatment
Use neutral silicone sealant for edge sealing. Do not use acidic, alkaline, or adhesive-containing sealants, which will corrode the sheet surface.
Step 7: Protective film handling
Keep the protective film during installation to avoid scratches. Remove it within 30 days after completion; long-term exposure will cause glue residue.
Step 8: Prohibit stepping on the sheet
Do not step directly on the sheet during construction. Use a pedal or wooden board to disperse pressure to avoid damage.
Following the above steps can ensure a 10–15 year service life of the PC sheet, waterproof and windproof, and no deformation or cracking.
