A twin wall polycarbonate sheet has two walls connected by vertical ribs, forming a single chamber of trapped air. That structure makes it the lightest panel in the range — from 0.80 kg/m² — while still delivering insulation far beyond solid glazing.
It is the panel specified when weight and cost per square metre decide the project: carports, pergolas, patio covers, small greenhouses and any structure where the supporting frame is light.
📞 Request a factory quote — FOB $2.50–3.50/kg, MOQ 5 tonnes or one 20 ft container. +2 01095990442
What Are Twin Wall Polycarbonate Sheets?
A twin wall polycarbonate sheet is an extruded panel built from two parallel walls joined by internal ribs. The single air chamber between them is what provides the insulation: still air conducts heat poorly, so the panel performs far better thermally than a solid sheet of the same thickness — at a fraction of the weight.
This is a distinct product from multiwall, which has four walls and three chambers. Twin wall is thinner, lighter and less expensive; multiwall insulates better and spans further. Both are hollow polycarbonate, but they are specified for different jobs.
All our twin wall sheets are extruded from 100% virgin resin with a co-extruded UV layer — fused into the material during extrusion, not sprayed on afterwards — and carry a 10-year warranty against yellowing.
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Technical Specifications
| Property | Value |
|---|---|
| Structure | 2 walls, 1 air chamber |
| Thickness range | 4 – 10 mm |
| Weight per m² | 0.80 – 1.70 kg |
| Light transmission | 83 – 91% (clear) |
| U-value | 2.9 – 3.5 W/m²K |
| Impact resistance | up to 250× glass |
| Service temperature | −40 °C to +120 °C |
| Thermal expansion | ≈ 3 mm per metre |
| Fire behaviour | Self-extinguishing, B1 by grade |
| UV protection | Co-extruded, blocks 99.9% (280–400 nm) |
| Standard sheet | 2,100 × 5,800 mm (12.18 m²) |
| Raw material | 100% virgin, no regrind |
| Warranty | 10 years against yellowing |
Thickness, Weight and Span
| Thickness | Weight/m² | Weight/sheet (2.1 × 5.8 m) | U-value | Span between supports |
|---|---|---|---|---|
| 4 mm | 0.80 kg | ≈ 9.7 kg | ≈ 3.5 W/m²K | up to 60 cm |
| 6 mm | 1.30 kg | ≈ 15.8 kg | ≈ 3.3 W/m²K | 60 – 80 cm |
| 8 mm | 1.50 kg | ≈ 18.3 kg | ≈ 3.1 W/m²K | 80 – 100 cm |
| 10 mm | 1.70 kg | ≈ 20.7 kg | ≈ 2.9 W/m²K | up to 110 cm |
Sheet area: 12.18 m². Spans are indicative — reduce by 20% in snow-load or high-wind regions and confirm against local code.
The most common specification error is choosing 4 mm on price and installing it over an 80 cm span. The panel deflects, holds water and fails early. Measure the actual spacing between purlins before selecting the thickness: if it exceeds 60 cm, 6 mm is the practical minimum.
Twin Wall vs Multiwall vs Solid
| Criterion | Twin wall (2-wall) | Multiwall (4-wall) | Solid |
|---|---|---|---|
| Walls | 2 | 4 | 1 (full thickness) |
| Thickness | 4 – 10 mm | 8 – 18 mm | 1 – 12 mm |
| Weight/m² | 0.8 – 1.7 kg | 1.6 – 2.9 kg | 1.2 – 14.4 kg |
| U-value | 2.9 – 3.5 W/m²K | 1.7 – 2.5 | ≈ 5.0 |
| Clarity | 83–91%, translucent | 83–91%, diffused | up to 90%, sharp |
| Max span | 60 – 110 cm | up to 160 cm | 60 – 80 cm |
| Cost per m² | Lowest | Low | Highest |
| Best for | Carports, pergolas, patios, small greenhouses | Commercial greenhouses, industrial roofs | Glazing, security, façades |
How to choose: twin wall when the cover is modest and the frame is light. Multiwall when insulation or span decides the specification. Solid when optical clarity is non-negotiable.
Types of Twin Wall Polycarbonate Sheets
Colours and Light Transmission
| Colour | Transmission | Effect |
|---|---|---|
| Clear | 83 – 91% | Maximum daylight |
| Opal | 25 – 45% | Even diffusion, no glare |
| Bronze | 35 – 50% | Solar control, warm tone |
| Smoke grey | 35 – 50% | Neutral shading |
| Blue / green | varies | Architectural, pool covers |
Standard colours carry no price premium. Custom RAL adds approximately 5%.
Finishes available: clear twinwall · frosted twinwall
A note on clear over occupied space: at 83–91% transmission, a clear roof over a patio becomes uncomfortably hot in summer. Bronze or smoke grey is usually the better call where people sit beneath it.
Applications
Carports and vehicle shelters — the volume application. 6 mm bronze or smoke over a light steel or aluminium frame.
Pergolas and patio covers — 4 mm or 6 mm depending on the rafter spacing.
Small and domestic greenhouses — 6 mm clear gives the light plants need at minimal structural load. Commercial growing usually specifies multiwall for the better U-value — see greenhouse panels and replacement panels.
Walkways and covered passages — narrow roofs where supports are naturally close together.
Interior partitions — light-transmitting dividers in offices and workshops.
Awnings over windows and doors — 4 mm is sufficient where the projection is short.
Pool covers — reduces evaporation and retains heat.
Sector pages: home & outdoor · agriculture · construction
Price
Polycarbonate is priced by the kilogram — which is why twin wall is the cheapest way to cover an area.
| Thickness | Weight/m² | Cost per m² (FOB) |
|---|---|---|
| 4 mm | 0.80 kg | $2.00 – 2.80 |
| 6 mm | 1.30 kg | $3.25 – 4.55 |
| 8 mm | 1.50 kg | $3.75 – 5.25 |
| 10 mm | 1.70 kg | $4.25 – 5.95 |
Factory price: $2.50–3.50 USD/kg FOB. One sheet covers 12.18 m².
Compare with solid: a 6 mm solid sheet weighs 7.2 kg/m² and costs around $21.60/m² at the same price per kilo — more than five times the twin wall of identical thickness.
Minimum order: 5 tonnes or one 20 ft container. Volume discounts apply by tonnage.
Price your order with our polycarbonate price & container calculator — weight, cost per m², cost per sheet and container fill.
Full pricing guide: polycarbonate sheet price · bulk orders
Container loading
Twin wall is light but bulky. A container reaches its volume limit well before its payload limit — one tonne of 10 mm twin wall occupies roughly twice the space of one tonne of thin solid sheet.
The practical consequence: a container loaded only with twin wall ships at perhaps 60–70% of its weight capacity, and the freight cost per square metre rises accordingly. Adding solid sheet to the same load uses the remaining payload without extra freight — worth raising with any customer ordering twin wall alone.
Installation
- Flutes vertical, running with the slope — always. Laid across, they trap condensation and the panel goes permanently opaque.
- UV face toward the sun — marked on the protective film. Reversed, the sheet yellows within months.
- Respect the span for the thickness: 60 cm for 4 mm, up to 110 cm for 10 mm.
- Oversize the holes — 3 to 5 mm clearance per side. The material expands about 3 mm per metre.
- Screws with EPDM sealing washers, tightened to contact without crushing. Thin panels mark easily under pressure.
- Seal the flutes — solid aluminium tape at the top, vented anti-dust tape at the bottom. Never the reverse.
- Minimum pitch 5%, 10–15% recommended. On thin panels, pitch matters even more: standing water deforms them.
- Neutral silicone only — acidic silicone attacks polycarbonate.
- Profiles matched to thickness — U-channel for edges, H-channel for joints, HCP-channel for reinforced assemblies.
Cutting: fine-tooth circular saw, 60 teeth minimum. Blow compressed air through the channels afterwards to clear swarf, then seal the edges. Full guide: how to cut polycarbonate sheets.
Common Mistakes
- Span beyond the rating — the single most frequent failure with 4 mm
- Flutes laid horizontally — trapped water, permanently opaque panel
- UV layer facing inward — yellowing within one season
- Profiles sized for another thickness — poor seal, water ingress
- Solid tape at the bottom — condensation cannot drain
- Screws torqued fully — cracks around holes by the first summer
- Pitch below 5% — standing water, deformation on thin panels
- Clear over a seating area — overheating in summer
- Walking on the panel — always use load-spreading boards
Specification and Ordering
| Term | Detail |
|---|---|
| Thickness | 4, 6, 8, 10 mm |
| Standard sheet | 2,100 × 5,800 mm |
| Custom length | up to 11,800 mm, cut to order |
| Colours | Clear, opal, bronze, smoke, blue, green, custom RAL |
| UV protection | Single or double sided |
| Coatings | Anti-drip for greenhouses, anti-fog |
| MOQ | 5 tonnes or one 20 ft container |
| Lead time | 14 days from order confirmation |
| Incoterms | FOB, CIF, CFR, EXW |
| Ports | Alexandria, Damietta |
Buying Direct from the Manufacturer
We extrude twin wall sheets in our own facility — 1,000 tonnes per month from 4,700 m² in Egypt, exporting to more than 60 countries.
- Factory pricing, no reseller margin
- Custom dimensions — length to your project, no paid-for offcuts
- 100% virgin resin, co-extruded UV protection
- 10-year warranty against yellowing
- CE certified (1871-CPR-RtF-846), ISO 9001, 14001 and 45001
- Private label available for distributor programmes
More on our capability: polycarbonate sheet manufacturers · full sheet range
Related products: multiwall · solid sheets · embossed · UV-resistant · accessories · hollow sheet types
Send your specification — quote within 24 hours.
WhatsApp: +2 01095990442 | info@gcrystal-pc.com
Frequently Asked Questions
What is a twin wall polycarbonate sheet?
An extruded panel with two parallel walls joined by internal ribs, forming a single air chamber. It is the lightest hollow panel in the range, from 0.80 kg/m², with U-values between 2.9 and 3.5 W/m²K.
What is the difference between twin wall and multiwall?
Twin wall has two walls and one air chamber; multiwall has four walls and three. Twin wall is lighter and cheaper per m² at 4 to 10 mm; multiwall insulates better and spans further at 8 to 18 mm.
How much does twin wall polycarbonate weigh?
From 0.80 kg/m² in 4 mm to 1.70 kg/m² in 10 mm. A standard 2,100 × 5,800 mm sheet weighs approximately 9.7 kg in 4 mm and 20.7 kg in 10 mm.
What span can twin wall polycarbonate cover?
Up to 60 cm in 4 mm, 60 to 80 cm in 6 mm, 80 to 100 cm in 8 mm and up to 110 cm in 10 mm. Reduce by 20% in snow-load or high-wind regions.
What thickness should I use for a carport?
6 mm is the practical standard, in bronze or smoke grey to limit heat. Use 8 mm where purlin spacing exceeds 80 cm or the region sees frequent hail.
How much does twin wall polycarbonate cost?
Factory pricing is $2.50 to 3.50 USD per kilogram FOB. In 6 mm at 1.30 kg/m², that works out to roughly $3.25 to $4.55 per m².
What U-value does twin wall polycarbonate achieve?
Between 2.9 W/m²K in 10 mm and 3.5 W/m²K in 4 mm — better than single glazing at 5.8, though multiwall reaches 1.7 for projects where insulation is critical.
Does twin wall polycarbonate yellow?
Not with a co-extruded UV layer, which blocks 99.9% of ultraviolet radiation. Our sheets carry a 10-year warranty against yellowing. Sheets with a sprayed surface coating, by contrast, degrade within a few years.
Which way do the flutes run?
Vertically, following the slope, without exception. Laid horizontally, the channels trap condensation and dust, and the panel becomes permanently opaque.
Can twin wall polycarbonate be cold-bent?
Yes, with a minimum radius of 175 times the thickness — no heating required. Bending must follow the direction of the flutes.
Is twin wall suitable for a greenhouse?
For domestic and small greenhouses, yes — 6 mm clear is the usual choice. Commercial growers generally specify multiwall for the better U-value, since heating cost over a large area outweighs the price difference.
What is the minimum order quantity?
5 tonnes or one 20 ft container. Samples are available for technical qualification before ordering.
