Polycarbonate vs Metal Sheet Roof: Which Should Your Shed Use?

Choose polycarbonate when the space under the roof has to stay bright: a terrace sitting area, a balcony, a kitchen garden or a utility area that would otherwise turn dark. Choose a metal sheet (colour-coated or galvalume steel, sometimes an insulated sandwich panel) when the job is to block the sun completely, take rough use and need almost no attention for years: a store room, a workshop, a parking bay or a generator enclosure. In the Gurugram and Noida summer, the difference you feel under each roof is mostly about heat and glare, so that is where to start.

This guide goes deeper on the roof sheet itself. If you are still deciding between a shed and a pergola, or want the RWA side of things, our terrace shed guide for Gurgaon covers that ground.

What exactly are you comparing?

Polycarbonate sheet is a tough, clear-to-tinted plastic. For sheds it comes in three common forms: multiwall (hollow, twin-wall or more, light and a little insulating), solid (looks like glass, very strong, heavier) and corrugated or profiled sheet that copies the shape of a metal roof. Good sheet has a UV-protected outer face, and that face must point at the sky.

A metal roof sheet is thin steel, usually zinc- or zinc-aluminium-coated and then colour-coated, rolled into a trapezoidal or corrugated profile so it can span between purlins. A PUF or EPS sandwich panel is two metal skins with an insulating foam core, used where heat under the roof really matters. Both sit on a frame, almost always mild steel for homes, which needs its own rust protection.

Which roof keeps a terrace cooler in a Delhi NCR summer?

Neither plain sheet keeps a terrace cool by itself. Clear polycarbonate passes light, and light becomes heat on the floor below. A bare metal sheet blocks light but gets very hot and radiates that heat downwards. What actually helps is a combination of choices:

• Tint or opal polycarbonate instead of clear, so glare and heat drop while the space stays bright.
• A gap at the sides or a raised ridge, so hot air under the roof can escape instead of pooling.
• Light-coloured metal sheet rather than dark, which reflects more of the sun.
• An insulated sandwich panel where you plan to sit under the roof at midday, or where the roof turns a terrace into a usable room.

If your terrace faces west and you want to sit out in the evening, opal or bronze polycarbonate with open sides is usually the comfortable middle. If the space is for storage or a washing machine, a light-coloured metal sheet is the practical answer.

How loud is each roof in the monsoon?

Rain on a bare metal sheet is loud, and in a July downpour it can drown out a conversation. Thin solid polycarbonate is a little quieter, and multiwall polycarbonate quieter again, because the hollow cells deaden the drumming. Sandwich panels are the quietest of all. If noise is already bothering you on an existing shed, our page on a shed that is noisy in the rain explains the fixes, from an underlay to a different sheet.

How long does each one last, and what wears it out?

A UV-protected polycarbonate sheet, fitted with the protected side up and cleaned gently, stays clear for many years. Sheet without that layer, or sheet fitted upside down, turns yellow and brittle much sooner. That is the cause behind most polycarbonate sheets yellowing. Cracks usually start at screw holes drilled too tight, with no room for the sheet to expand in the heat; see polycarbonate sheet cracked.

A coated metal sheet lasts a long time as long as its coating survives. What shortens its life is a scratch from a ladder, a cut edge left raw, or water that sits in a low spot. In a factory area or near a busy road, dust that holds moisture on the sheet also speeds things up.

What does each roof ask of the frame?

Polycarbonate is light, but it is flexible, so it needs purlins at closer spacing than metal sheet, and it must not be fixed tight: each screw goes through an oversized hole with a sealing washer so the sheet can move as it heats and cools. Metal sheet spans further between purlins and takes self-drilling screws with washers. Both need a slope, usually a few degrees at least, so water runs off instead of ponding.

The steel frame underneath needs the same care either way: primer and paint, powder coating on pre-made parts, or hot-dip galvanising where the budget allows. A frame that is welded on site and painted in a hurry is the commonest cause of a shed roof sagging or rust streaks a couple of years later.

How do they compare on upkeep?

A blocked gutter overflows onto the wall or the neighbour's terrace whichever sheet you choose; shed gutter overflowing covers how to size and slope one so it copes.

Which roof suits which shed?

Terrace sitting area or balcony

Polycarbonate, usually tinted or opal. You keep the open-air feel and the daylight. A polycarbonate terrace shed on an MS frame is the usual build, and if you want something lighter overhead, an MS pergola with a poly sheet on top is another route.

Car parking

Either works. Polycarbonate keeps a porch bright and looks lighter from the street; metal sheet is cheaper to maintain, hides bird droppings and blocks the sun on the car's paint. Our car parking shed options guide goes through layouts.

Store room, workshop or plant room

Metal sheet, or sandwich panel if people work under it. Factories and warehouses usually go this way; see glass and metal work for warehouses and factories.

Entrance canopy

For a small, premium canopy over a front door, a glass canopy in laminated glass is an option too, because it stays clear for good and doesn't scratch the way plastic does.

How is a shed roof priced?

Shed work is priced after a site visit, because the frame, height, span and access change the cost more than the sheet does. The quote is normally worked out on the roof's plan area, and you can get a rough figure for that with our area calculator before the visit. What changes the number: the sheet type and thickness, the frame section sizes, the finish on the steel, the height off the floor, whether the roof is fixed to a wall or freestanding, and the gutter. Our terrace shed cost guide explains each factor.

We build sheds across Delhi NCR, from builder floors in Gurgaon and Noida to houses in Faridabad and Ghaziabad. Book a site visit and the team will measure the space, look at the sun and the drainage, and recommend the sheet that fits how you will use it.