Dual Colour Polycarbonate

The bronze outer layer reflects much of the sun's heat before it reaches the room, and the opal inner layer scatters what does get through. Together they cut solar heat by up to 50% compared with a clear sheet, more than bronze or opal alone. Light transmission is about 8% at 25mm, so expect a shaded room rather than a bright one.

The bronze side faces the sun and the opal side faces the room. The bronze face is also the UV-protected face, marked by the printed protective film, so the two rules agree. Leave the film on until the sheet is in place. Fitted upside down, the sheet loses its UV protection and will yellow and crack within a couple of years.

About 8% at 25mm, and around 8 to 10% at 32mm and 35mm. That sounds very little, but the opal inner layer spreads that light evenly, so the room reads as softly shaded rather than dark. Compare it with about 62% for clear 25mm. If you want a brighter room with a little less heat, plain bronze may suit you better.

Yes. A south-facing conservatory takes full sun for most of the day, and that is where the up to 50% cut in solar heat pays off. It also suits sunrooms and rooflights that overheat. On a north-facing or shaded roof the same sheet would leave the room dim for little benefit, so clear or opal is the better choice there.

The opal inner face reflects your artificial light back into the room, so at night the ceiling reads as a soft pale surface rather than a black ceiling. A plain bronze or clear roof looks dark once the sun goes down. The opal layer adds no light, but it makes the room feel enclosed and lit rather than open to the night sky.

What are pre-taped edges on multiwall polycarbonate sheets?

Pre-taped edges mean that protective tapes have already been applied to the open ends of your multiwall polycarbonate sheets before delivery, saving you time during installation.

At The Polycarbonate Store, our complimentary pre-taping service is available on 10mm, 16mm, 25mm, 32mm and 35mm twinwall and multiwall polycarbonate sheets.

The two open ends of the sheet's hollow channels (flutes) are taped differently:

• Top edge – Aluminium sealing tape: Solid silver tape seals the upper end of the flutes, helping prevent water, dirt and debris from entering.
• Bottom edge – Anti-dust breather tape: Helps prevent dust and insects from entering while allowing ventilation and moisture to escape, reducing the risk of condensation build-up.

For a standard sloping roof, the aluminium-taped edge must be positioned at the top, with the breather-taped edge at the bottom, towards the gutter. The tapes should remain in place during installation.

Important: Pre-taping only covers the two open flute ends, not all four sides of the sheet. It does not replace the need for PVC sheet end closures, which should be fitted over the taped edges to provide additional protection and a neat finish. Pre-taping also does not completely prevent condensation.

During preparation, approximately 10mm of protective film is removed from each taped end. This may leave a visible preparation line, which is normally concealed by the roofing accessories. If you need to trim a pre-taped sheet, the newly exposed flutes must be cleaned and re-taped correctly before installation.

For curved roofing or other applications, the required tape arrangement may differ. Please contact us before ordering if you are unsure.

For further information, read our full guide: What Do Pre-Taped Edges Mean on Multiwall Polycarbonate Sheets?