Multiwall Polycarbonate Sheet
Twin-wall, triple-wall and honeycomb structures — lighter and warmer than solid sheet, for roofing and greenhouses.
Multiwall polycarbonate — hollow sheet, twin-wall, or in Chinese usage 阳光板 — carries internal ribs that trap air between two or more skins. The trapped air does two useful things: it insulates, and it lets the sheet span further for its weight.
A 6 mm twin-wall sheet weighs about 1.3 kg/m². The same area in 6 mm solid sheet weighs over 7 kg. On a greenhouse roof that difference decides the entire frame specification.
Specification
| Property | Specification |
|---|---|
| Structures | Twin-wall, triple-wall, X-structure, honeycomb |
| Thickness | 4 mm – 20 mm |
| Widths | 1220 mm and 2100 mm standard |
| Length | Cut to order; commonly 5.8 m or 11.8 m for container loading |
| Weight (6 mm twin-wall) | Approx. 1.3 kg/m² |
| Light transmission | 78–82% clear; opal and bronze options available |
| UV protection | Co-extruded on the exposed face as standard |
| Colours | Clear, opal, bronze, blue, green |
Choosing a structure
- Twin-wall (4–10 mm) — the default for carports, walkways and small greenhouses. Cheapest per square metre and easiest to handle.
- Triple-wall and X-structure (8–16 mm) — better insulation and longer spans. Worth the cost where heating bills or snow loads matter.
- Honeycomb (10–20 mm) — the stiffest construction for its weight, used where the span is long and the frame is minimal.
Installation points that cause failures
Three mistakes account for most multiwall complaints, and none of them are sheet defects:
Ribs installed horizontally. The channels must run down the slope so condensation drains out. Horizontal ribs trap water, and the panel greens up within a season.
Ends left open or fully sealed. The top edge takes solid tape, the bottom edge takes vented tape. Sealing both ends traps moisture inside the flutes.
UV face installed downwards. The protected face is marked on the film. Fitted upside down, the sheet yellows in two to three years and the warranty is void.
Typical applications
- Agricultural and horticultural greenhouses
- Carport and vehicle canopy roofing
- Walkway and platform covers
- Industrial roof lights and daylighting strips
- Swimming pool enclosures
Minimum order and lead time
This grade ships from 100 m² or 1 tonne — a trial pallet, not a full container. Standard sizes and stock colours run in 7–10 days; non-standard thickness or width in 12–18 days; add 3–7 days for CNC cut-to-size work. Quoted in USD on FOB, CIF or DDP terms. Full detail on the MOQ, lead time & shipping page.
Questions buyers ask
What span can multiwall polycarbonate cover?
It depends on thickness, structure, purlin spacing and local snow and wind loading. As a rough guide, 6 mm twin-wall suits purlins at 700 mm; 16 mm triple-wall reaches beyond 1500 mm. Send the frame drawing and load requirement and we will confirm.
Which side faces the sun?
The face carrying the printed protective film with the UV marking. Fitting it downwards removes the UV protection from where it is needed and the sheet yellows quickly.
Can multiwall sheet be curved?
Yes, cold-curved along the rib direction only, to a minimum radius of about 175× the sheet thickness. It cannot be curved across the ribs.