Polycarbonate Roofing Sheet

Q: What thickness of polycarbonate do I need for a roof?

It is set by purlin spacing and load, not preference. As a guide, 6 mm twin-wall suits purlins around 700 mm apart; 16 mm triple-wall reaches beyond 1500 mm. Send the frame drawing and your local snow load and we will specify it.

Roof lights, walkway covers and daylighting — where span, load and UV orientation decide the specification.

Roofing is the largest single use of polycarbonate, and the one where specification errors are most expensive — because a roof that leaks or yellows has to be taken off again.

Three decisions drive the whole job: the span between purlins, the local snow and wind load, and which face carries the UV protection. Those inputs guide grade selection; service life still depends on the offered UV grade, fixing, environment and maintenance.

Polycarbonate roofing sheet on a covered walkway

New to polycarbonate roofing systems? Our explainer covers how the panels, profiles, fasteners, seals and drainage work together: what is polycarbonate roofing.

Choosing the construction

Requirement	Specify
Maximum light, short spans	Solid sheet, 3–6 mm
Insulation matters (heated space)	Triple-wall or X-structure, 10–16 mm
Long spans, light frame	Honeycomb, 10–20 mm
Budget covered walkway	Twin-wall, 6–8 mm
Hail or impact risk	Solid grade and thickness confirmed against the project impact requirement and support detail

The three failures we see most

UV face fitted downwards. The protected side is marked on the film. Installing a one-sided UV-protected sheet upside down exposes the unprotected face and can accelerate weathering; timing depends on the grade and site conditions.

Ribs running across the slope. Multiwall channels must run down the fall so condensation drains. Across the slope, water sits in the flutes and algae grows.

No allowance for thermal movement. Polycarbonate expands roughly 3 mm per metre over a 50 °C swing. Fixing holes must be oversized and screws must not be tightened down hard, or the sheet buckles in summer and cracks at the fixings.

Typical applications

Industrial roof lights and daylighting strips
Covered walkways and link corridors
Patio, terrace and pergola roofs
Stadium and grandstand covers
Agricultural building roof panels

Minimum order and lead time

For polycarbonate roofing sheet projects, SinoPlastix checks roofing material selection before confirming the material. Send the span or finished dimensions, exposure and load conditions, preferred appearance, fabrication needs, and quantity. Standard stock sizes and colours normally run in 7–10 days; non-standard extrusion in 12–18 days; allow another 3–7 days for CNC work. The published starting point is 100 m² or 1 tonne, quoted in USD on FOB, CIF or DDP terms. See MOQ, lead time and shipping for planning details.

Questions buyers ask

What thickness of polycarbonate do I need for a roof?

It is set by purlin spacing and load, not preference. A generic thickness-to-span number is not a design approval: the offered section, rib geometry, support, slope, fixings and local design load control spacing. Send the frame drawing and site loads so the exact sheet load table and project engineer can be used.

How long does polycarbonate roofing last?

For the specified UV-protected grade, ask for the test conditions behind its ten-year ≥ 85% light-transmission target. Service life depends on grade, thickness, climate, loading, fixing and maintenance; a reversed or unprotected face can weather faster, but no fixed failure year applies.

Can you supply sheet cut to my exact roof lengths?

Yes — cutting to length at the factory removes site waste and offcuts entirely. Send the cutting schedule with your enquiry.

Request a quote MOQ & shipping

For a translucent daylighting strip that has to drop into an existing steel roof run, the profile decides both the seal at the side lap and where the fixings can go — see corrugated polycarbonate profiles.

Rooflight and daylighting specification inputs

For a rooflight, canopy or covered walkway, sheet thickness cannot be selected from opening width alone. The review needs the sheet construction, support spacing, panel length, roof slope, fixing system, project location and applicable wind, snow or maintenance loads. Published examples are planning references, not a substitute for project engineering.

Roofing route	Useful when	Critical detail
Multiwall sheet	Insulation and lightweight daylighting matter	Channel direction, edge sealing, drainage and compatible profiles
Corrugated sheet	The panel must match an existing metal or fibre-cement profile	Profile drawing, overlap, support and fixing position
Solid sheet	Clear view, impact resistance or formed geometry matters	Support, thermal movement, abrasion exposure and finished drawing

Thermal movement and fixing

Provide the installed panel length and expected temperature range so expansion clearance can be reviewed. Holes, washers and profiles must allow movement without concentrating stress at an edge. Do not describe a roof panel as walkable unless the complete supported assembly has been engineered and approved for that load.

Use the roofing load and span guide for planning inputs, then submit the support layout through the roofing quotation route.

From the factory