The 8mm clear polycarbonate sheet is a twin-wall glazing panel for greenhouse and high tunnel 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.

Technical Specifications

Q: What is 8mm twin-wall polycarbonate used for?

A: 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.

Q: How do I seal the cut ends of the sheet?

A: 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.

Q: How do I fasten polycarbonate without cracking it?

A: 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.

Q: What lengths does the 8mm sheet come in?

A: 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.

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Need a custom size, or help figuring out how many sheets your end walls take? Contact CT Greenhouse for a quote.