Heat Guard Polycarbonate

By up to 50% compared with a clear sheet. The silver reflective outer layer bounces much of the sun's heat away before it enters the sheet, and the opal inner layer diffuses what remains. Light transmission is about 7% at 25mm, so the room is shaded and cooler rather than bright. Winter insulation matches clear of the same thickness.

The silver reflective side faces the sky. It is also the UV-protected face, marked by the printed protective film, so both rules point the same way. Keep the film on until the sheet is in position, then peel it off. Fitted the wrong way, the sheet loses its heat-reflecting benefit and the unprotected face will yellow and crack within a couple of years.

A bronze or opal tint absorbs and scatters light within the sheet, which cuts glare but still lets a good share of the sun's heat through. Heat guard's silver outer layer reflects that heat before it enters the sheet. That is why it cuts solar heat by up to 50%, more than a plain tint, while passing about 7% of light at 25mm.

The same as standard multiwall of the same thickness: 900mm for 25mm, and 1000mm for 32mm and 35mm. The reflective layer does not change the sheet's stiffness. The manufacturer allows wider spans at light loads, but these are the safe DIY figures. Check your wind and snow exposure, or call the technical team before ordering.

Yes. Heat guard makes most sense on a south-facing conservatory, sunroom or rooflight that overheats in summer, where the up to 50% cut in solar heat is worth the loss of daylight. On a shaded or north-facing roof it leaves the room dim for little gain. We stock it in 25, 32 and 35mm, cut to size.

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?