The 8mm clear polycarbonate sheet is a twin-wall glazing panel for greenhouse and high tunnel roofs, end walls, doors, and side walls. Its hollow twin-wall structure traps a layer of air for insulation, so it holds heat better than single-layer glazing while staying clear enough to grow under. At 4' wide in lengths from 8' to 24', you can size it to most framing with minimal cutting.
The clear sheet has an anti-fog (no-drip) inner surface that helps condensation run off instead of beading up, and it resists hail and impact much better than glass. It's backed by a 10-year warranty. Seal the cut ends with aluminum foil seal tape on the top edge and vent tape on the bottom, then fasten it with neoprene washers and self-tapping screws.
Key Benefits
Insulating twin-wall
the hollow core traps air between two walls for better heat retention than single-layer glazing, which can mean lower heating costs.
Anti-fog (no-drip) surface
helps condensation sheet off and run down instead of beading and falling on your plants.
Impact and hail resistant
withstands weather and impact much better than glass, and it's lightweight to handle and install.
Backed by a 10-year warranty
a long-service glazing choice for a permanent end wall or greenhouse covering.
Technical Specifications
| Thickness | 8mm |
|---|---|
| Wall structure | Twin-wall (hollow) |
| Width | 4' |
| Available lengths | 8' to 24' (see options below) |
| Material | Clear polycarbonate |
| Light transmission | 80% |
| Warranty | 10 years |
Available Lengths
Every sheet is 4' wide. Choose your length:
- 4' × 8'
- 4' × 10'
- 4' × 12'
- 4' × 14'
- 4' × 16'
- 4' × 18'
- 4' × 20'
- 4' × 22'
- 4' × 24'
Custom 6' widths, plus blackout and light-diffusing sheets, are available on request.
Frequently Asked Questions
What is 8mm twin-wall polycarbonate used for?remove
It's a clear, insulating glazing panel for greenhouses and high tunnels, most often on end walls, doors, and side walls. The twin-wall air space holds heat better than single-layer glazing while letting plenty of light through.
How do I seal the cut ends of the sheet?add
Seal the top edge with solid aluminum foil seal tape and the bottom edge with breathable vent tape, then fit an edge profile or U-channel over both. That keeps the flutes clear while letting any moisture drain out the bottom.
How do I fasten polycarbonate without cracking it?add
Pre-drill holes slightly oversized so the panel can expand and contract, use self-tapping screws with neoprene washers, and drive each screw just until the washer seats, no further. Keep fasteners back from the panel edge.
What lengths does the 8mm sheet come in?add
All sheets are 4' wide, in lengths from 8' up to 24' in 2-foot steps. Custom 6' widths, plus blackout and light-diffusing options, are available on request.
Can I use 8mm polycarbonate on a greenhouse roof?add
Yes. The 8mm twin-wall sheet is made for greenhouse and high tunnel roofs, end walls, doors, and side walls. [VERIFY: recommended purlin spacing or roof pitch, if you publish one]
Should I choose 6mm, 8mm, or 10mm polycarbonate?add
[VERIFY: which thicknesses CT Greenhouse sells, and the plain-language difference in insulation, stiffness, and light between them]
Which side of the sheet faces out?add
[VERIFY: UV-protected side marking, and whether the film label shows which side goes out]
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