Project Overview
Modern commercial agriculture demands growing environments that balance natural light transmission, thermal insulation, and structural durability — all while keeping operational costs manageable. This 10,000-square-meter multi-span greenhouse complex in northern China was designed to meet exactly these requirements, and multiwall polycarbonate sheets were the material of choice for the entire roofing and cladding system.
The facility spans multiple connected bays, each 8 meters wide and 40 meters long, creating a total covered growing area that supports year-round vegetable and flower production. Unlike traditional glass greenhouses that require heavy steel substructures and frequent maintenance, the polycarbonate solution reduced the overall framing weight by nearly 60% while delivering superior insulation performance.
The Challenge
The project site presented three significant challenges. First, the region experiences extreme temperature swings — from -25°C winter lows to 38°C summer highs — meaning the cladding material needed exceptional thermal insulation to maintain stable interior temperatures without excessive heating or cooling costs. Second, the greenhouse required maximum natural light transmission for optimal photosynthesis, but direct UV exposure would degrade conventional plastic films within 2-3 seasons. Third, the multi-span design created long, continuous roof planes that demanded a material light enough to not overburden the framing, yet strong enough to withstand snow loads up to 40 kg/m² and occasional hailstorms.
Our Solution: Multiwall Polycarbonate Sheets
After evaluating single-layer films, tempered glass, and fiberglass panels, the project team selected 8mm twin-wall polycarbonate sheets for the roof and 6mm twin-wall panels for the side walls. The multiwall construction — with its internal rib structure creating insulating air channels — offered the ideal combination of properties:
- Thermal Performance: U-value of 3.0-3.2 W/m²·K, reducing heating costs by approximately 40% compared to single-layer glass
- Light Transmission: 80-82% visible light transmission for the clear panels, with even light diffusion that eliminates scorching hot spots on plants
- UV Protection: Co-extruded UV layer on the outward-facing surface blocks 99% of harmful UV radiation, protecting both the crops and the panel itself from yellowing
- Impact Resistance: 200 times stronger than glass at equivalent thickness, surviving hailstorms that would shatter conventional glazing
- Weight: At just 1.5-1.7 kg/m², the panels significantly reduced structural steel requirements
Technical Specifications
| Parameter | Roof Panels | Wall Panels |
|---|---|---|
| Material | Multiwall (Twin-Wall) PC | Multiwall (Twin-Wall) PC |
| Thickness | 8mm | 6mm |
| Width | 2100mm (standard) | 2100mm (standard) |
| Length | Custom cut, up to 12m | Custom cut, up to 6m |
| Color | Clear (transparent) | Clear (transparent) |
| UV Protection | Co-extruded, 50μm | Co-extruded, 50μm |
| U-Value | 3.0-3.2 W/m²·K | 3.3-3.5 W/m²·K |
| Light Transmission | 80-82% | 80-82% |
| Weight | ~1.7 kg/m² | ~1.5 kg/m² |
| Fire Rating | B1 / UL94 V-2 | B1 / UL94 V-2 |
| Temperature Range | -40°C to +120°C | -40°C to +120°C |
The twin-wall structure creates a series of parallel air channels that act as thermal buffers — similar to double-glazed windows but at a fraction of the weight. Paired with an aluminum glazing bar system and EPDM gaskets, the installation achieved full weather sealing while accommodating the 3.5mm/m thermal expansion typical of polycarbonate.
Results
The greenhouse has now completed three full growing seasons. Key outcomes include:
- Energy Savings: Heating costs reduced by 38% in winter months compared to the facility’s older single-layer film greenhouses
- Crop Yield: Consistent 15-20% yield improvement attributed to uniform light diffusion eliminating hot spots
- Zero Panel Replacement: After three years of extreme weather cycles, not a single panel has required replacement — the UV-protected surface shows no visible yellowing
- Reduced Maintenance: The smooth, non-porous surface sheds dirt naturally with rainfall; no specialized cleaning regime needed
Why Jietai for Your Greenhouse Project
Jietai supplies multiwall polycarbonate sheets in the full range of thicknesses (4mm to 30mm), structures (twin-wall, triple-wall, four-wall, X-structure, and honeycomb), and custom colors to match any agricultural or commercial greenhouse specification. Our 2100mm standard width minimizes cutting waste on large-scale installations, while our co-extruded UV protection layer is engineered for long-term outdoor performance — not just a thin surface coating.
Available thicknesses range from 4mm to 30mm, and we supply panels cut to length up to 12 meters for projects that demand uninterrupted roof spans. Whether you’re planning a small hobby greenhouse or a multi-hectare commercial growing facility, our team can help you select the right panel specification and connect you with experienced installers.
Contact our team for a quote on your greenhouse polycarbonate requirements.
