Polycarbonate Skylight Sheet for Industrial Roofs

Polycarbonate skylight sheet is translucent polycarbonate, solid profiled or multiwall, matched to the surrounding metal roof sheet to bring daylight into industrial and warehouse spaces. Its service life depends on the co-extruded UV-protected face being installed upward, and skylight area trades lighting savings against solar heat gain.

By Dhruv Agarwal · · 1 min read

What it is

Translucent polycarbonate sheet, profiled to match the metal roof sheet around it, used to bring daylight into a large industrial or warehouse space without electric lighting.

Specification at a glance

PropertyTypical specification
TypeSolid profiled, or multiwall
Thickness1.5mm — 3mm profiled; 6mm — 25mm multiwall
UV protectionCo-extruded layer, one or both faces
Light transmissionSpecified as a percentage
ProfileMatched to the adjacent metal sheet
Fire classNamed EN 13501-1 class

Solid profiled against multiwall

Solid profiledMultiwall
InsulationPoorBetter, sealed air cells
Light qualityClear, higher transmissionDiffused, softer
StrengthGood impact resistanceGood, lighter
DetailingLaps like the metal sheetNeeds sealed edge tapes
UseStandard industrial roof lightsConditioned or diffused-light spaces

The daylight and heat trade-off

Roof lights cut lighting load — and that saving works against the ECBC lighting power density target — but they also admit solar heat directly onto the working floor. In an air-conditioned building that heat becomes cooling load.

The practical answer on most Indian industrial roofs is a modest percentage of roof area, distributed evenly for uniform light rather than concentrated, with diffusing multiwall used where glare on a working plane matters.

Where projects go wrong

  • UV face installed downward. The single most common and most damaging error.
  • Too much skylight area, turning a lighting saving into a cooling cost.
  • Fixings through the sheet without oversized holes. Polycarbonate expands considerably more than steel; pinned sheets crack around the screws.
  • Edges of multiwall left unsealed, so dust and moisture enter the cells and the sheet clouds permanently.
  • Walking on roof lights. They are not a walking surface; many industrial roof falls happen through them.

Standards referenced

Skylight and daylighting provisions under ECBC 2017. Wind loading under IS 875 (Part 3). Reaction-to-fire classification to EN 13501-1.

Standards referenced

  • ECBC 2017 — Building envelope — skylights and daylighting (Bureau of Energy Efficiency)
  • IS 875 (Part 3) — Wind loads — roof cladding (Bureau of Indian Standards)
  • EN 13501-1 — Reaction to fire classification (CEN-CENELEC)

Frequently asked

Commonly 3 to 5 percent of roof area, and ECBC 2017 sets limits alongside daylighting provisions. More than that and solar heat gain starts to outweigh the lighting benefit, especially in Indian conditions where the roof takes intense sun for most of the day. The right figure depends on internal working plane requirements and whether the space is air conditioned.

The UV-protected face, which is marked on the protective film. Polycarbonate degrades rapidly under direct ultraviolet, so the co-extruded UV layer is what gives the sheet its service life. Installing a sheet upside down is an easy site error, it is invisible on the day, and it yellows and embrittles within a couple of seasons.

Polycarbonate has far higher impact resistance and better long-term clarity, so it is the safer choice where anything might fall on the roof or where people access it. FRP is cheaper and more rigid but yellows and can become brittle with age. For a building with a long design life, polycarbonate with a proper UV layer is usually the better investment.

Related

More in Materials

All Materials →

Planning an office or commercial project?

Tell us what you are planning. Message our team on WhatsApp, call us, or leave your number and we will call you back.

Chat on WhatsAppCall +91 88829 10969

Request a callback