Polycarbonate sheds · UV damage

Polycarbonate sheet turned yellow: why it happens and what to do in Gurgaon

Polycarbonate turns yellow and brittle from UV damage. Good sheet has a UV-protective layer on one face; if the sheet had none, was fitted upside down, or is past its life, the sun breaks it down. Yellowing can't be polished out; the fix is new UV-protected sheets fitted the right way up.

Updated 8 October 2026Gurugram & Noida

Clear polycarbonate roofing sheets on a terrace shed frame

A clear polycarbonate shed looks bright and clean the year it goes up. A few Gurugram summers later, the light under it has turned a dull yellow, the sheet looks hazy, and it cracks when someone leans a ladder against it. This is one of the most searched shed problems, and the honest answer is short.

The short answer

Yellowing is the sun breaking down the polycarbonate. Once it has started, it can't be cleaned, polished or painted away. The sheet needs replacing, and the replacement needs to be UV-protected and fitted with the protected face up.

Why polycarbonate yellows

No UV protection on the sheet

Quality polycarbonate sheet is co-extruded with a UV-blocking layer on one face. Cheaper sheet may have none, or a very thin one. On a terrace exposed to a full North Indian summer of high UV and 45°C heat, unprotected sheet yellows fast.

The sheet was fitted upside down

The UV-protected side is marked on the protective film. If the film was peeled without noting which side was which, or ignored, the sheet goes up with the protected face inside. It then ages as if it had no protection at all. This is surprisingly common.

Protective film left on in the sun

The peel-off film is meant to come off at installation. Left on through a summer, it bakes onto the sheet and leaves a patchy, cloudy surface that's hard to remove.

Chemical attack

Some sealants, cleaners and paints with solvents attack polycarbonate, causing crazing (fine cracks) and cloudiness, usually near joints and screw holes.

Age

Even well-protected sheet has a working life. After many years of NCR sun, some loss of clarity and yellowing is normal.

Yellow polycarbonate sheet: cause and outcome
What you see	Most likely reason	Can it be saved?
Even yellow tint across the whole roof	UV damage, no or failed UV layer	No; replace with UV-protected sheet
Yellow on some sheets, clear on others	Those sheets fitted upside down	Replace the affected sheets
Patchy, flaky haze	Protective film baked on	Sometimes partly; usually replace
Fine cracks near screws and joints	Solvent sealant or over-tightened screws	Replace damaged sheets, correct fixings
Brittle, cracks when pressed	Advanced UV breakdown	Replace; it's also a safety issue

What you can check

Look at the sheet edges for printed markings; they often say which face is UV-protected and the brand.
Compare sheets. If only some have yellowed, those were probably flipped.
Press a sheet gently from below with a broom handle. If it crackles or flexes unevenly, it has gone brittle.
Clean with mild soap and water and a soft cloth only. Solvents and abrasive cleaners make it worse.

Replace the sheets, or the whole shed?

If the steel frame is sound, straight and painted, only the sheets need replacing, along with new EPDM-washered fixings and sealing tapes. Rebuild the whole polycarbonate terrace shed when the frame has rusted, sagged or was built too flat (which also causes leaks, covered in terrace shed leaking). For covered parking with the same issue, the same applies to a car parking shed. Some people switch to a tinted or opal sheet to cut glare and heat, or to an MS pergola with a partly open roof. The terrace shed guide for Gurgaon compares sheet types, and the terrace shed cost guide explains what changes the price.

How FabWise handles yellowed sheet

Send a photo of the shed from below and above if possible, a close-up of a sheet edge with any markings, and the frame. We'll tell you whether it's a sheet change or a full rebuild. If we need to measure, the visit is ₹99, adjusted against the bill if you go ahead. Shed work is quoted after the visit; there's no published rate.

Make the next roof last

Ask for UV-protected sheet and check the protected face is up before fixing.
Remove the protective film at installation, not later.
Use EPDM washers, oversized holes and polycarbonate-compatible sealant only.
Wash the roof gently with water after dust storms; dust baked on in summer holds heat and dulls the sheet.

Browse the sheds and pergolas catalogue, or see sheds and pergolas in Noida. For balcony safety around an old shed, see railing wobbling. Send us a photo on WhatsApp and we'll tell you if the frame can stay.

Common questions

Why did my polycarbonate sheet turn yellow?

Ultraviolet light from the sun has broken the plastic down. That happens fastest when the sheet has no UV-protective layer, or when it was fitted with the protected face underneath. Strong summer sun in Gurgaon and Noida speeds it up. Older sheets also yellow slowly with age.

Can yellow polycarbonate be cleaned or polished back to clear?

No. The yellow is in the plastic, not on the surface. Cleaning removes dust and makes it look a little better, but the tint stays. Abrasive polish and solvents make it worse. Replacing the sheets with UV-protected ones is the only real fix.

How do I know which side of a polycarbonate sheet faces up?

The UV-protected face is marked on the protective film, usually with printed text saying which side goes to the sun. Remove the film only after the sheet is positioned the right way. Once the film is gone, the printed marking along the edge, if present, is the only clue.

Polycarbonate sheet peela ho gaya hai, kya ise badalna padega?

Haan. Yellowing is sun damage and it can't be reversed. If the sheet has also gone brittle, it can crack in a storm. If the steel frame is still good, only the sheets need replacing. Send a photo on WhatsApp and we'll tell you whether the frame can stay.

Is tinted polycarbonate better for a terrace in Gurgaon?

Tinted or opal sheet cuts glare and some heat compared with clear sheet, which many people prefer under 45°C summers. It still needs UV protection, and it lets in less light. The choice depends on whether you want brightness or shade. The terrace shed guide compares the options.