Yes, polycarbonate can be part of a low-slope roof, but a level sheet that allows water to pond is not a finished roof design. Select the PC panel system first, then set its permitted pitch, supports, joints, flashing and movement details. SinoPlastix can quote custom PC sheet and cut panels from your drawing; the project team approves the complete roof and drainage design.
Send a low-slope roof section See PC roofing options
“Flat” still needs a route to the gutter
For a named example, the POLYVANTIS LEXAN THERMOCLEAR multiwall guide advises a minimum 5° slope, about 9 cm fall per metre, for sloped glazing drainage. Palram’s SUNGLAZE solid-PC roof system brochure also recommends 5° and says a rafter design is recommended for lower slopes. These are product-specific published guides, not one universal minimum for all PC systems. The selected supplier’s current installation guide and local design rules control.
At 5°, rise is approximately run × tan(5°): a 2 m horizontal run needs about 175 mm geometric rise, and a 4 m run about 350 mm. That is a layout illustration; beam deflection, construction tolerance, ponding and drainage provisions may change the design requirement. Do not treat it as a final roof-section calculation.
Choose the panel-and-joint route before the sheet thickness
| Route | Useful when | Detail to obtain before ordering |
|---|---|---|
| Solid PC in glazing bars | Clear view and a custom framed skylight matter. | Edge capture, gasket, movement allowance, flashing and support calculation. |
| Multiwall PC in profiles | Daylight with a cellular insulating section matters. | Channel direction, end closure, drainage, UV face and system span table. |
| Standing-seam PC panel system | Continuous daylight strips and a matched joint system are specified. | Exact panel/profile pair, seam, clips, slope, transitions and supplier instructions. |
For sheet construction see solid versus multiwall PC. For a load-dependent span see the PC roof load/span guide. This page answers the separate low-slope drainage and joint question.
Check the places where low-slope roofs fail
Show pitch, low points, gutters, outlets and a way to avoid ponding after deflection.
Draw end stops, upstands, lap direction, flashing, gaskets and service penetrations.
Allow temperature movement and safe cleaning access. Never use a PC panel as a walking surface.
For multiwall construction, orient channels down the slope and specify breathable/drainable lower-end closure to the offered system guide. Obtain the exact panel’s UV-face marking, support and fastening instructions. A sample sheet by itself does not establish watertightness, structural capacity or code compliance for an installed roof.
Send the roof section for a useful PC quotation
SinoPlastix can quote a custom PC grade, sheet form, colour, cut size and specified fabrication. Common original reports are available privately from sales. The actual quote confirms price and lead time for the order complexity. Copy these fields into the RFQ:
Common questions
Can a polycarbonate panel sit completely level on a roof?
A level panel can allow water to pond. Use a roof-system detail with a designed drainage path and the selected system’s slope requirement, accounting for deflection and construction tolerances.
Is 5° the minimum for every PC roof?
No. It is a published recommendation for the named THERMOCLEAR and SUNGLAZE examples above. Check the current guide for the exact panel system, local rules and the engineer’s drainage design.
Will SinoPlastix design the waterproof roof?
SinoPlastix can quote custom PC sheet and specified fabrication from the roof schedule. The project designer, system supplier and installer determine and approve loads, drainage, joints and waterproofing for the complete roof.