What should a polycarbonate roofing warranty actually cover?

A credible warranty should specify measurable thresholds: a minimum light transmission retention percentage at a defined year mark, a maximum Yellowness Index change, coverage against co-extrusion delamination, and structural integrity under normal service conditions — not just a headline number of years.

What's the difference between a product warranty and a system warranty?

A product warranty covers the polycarbonate panel itself. A system warranty covers the panel plus the fixing hardware and workmanship, and is usually only offered when installation is carried out or certified by an approved installer. A system warranty removes ambiguity about whether a failure was caused by the panel or the installation.

What voids a polycarbonate roofing warranty?

Common exclusions include installation defects unrelated to the panel, damage from incompatible cleaning agents such as solvents or ammonia-based cleaners, impact beyond the panel's tested class, and normal batch-to-batch colour variation. A warranty with no stated exclusions is a bigger red flag than one with a reasonable exclusions list.

Why do some polycarbonate warranties last longer than others?

Longer warranty periods usually track real differences in manufacturing quality — thicker co-extruded UV layers, tighter tolerances, and documented third-party test data. A supplier who can show LT retention and Yellowness Index data at 5 and 10 years can substantiate a longer warranty; one who can't is making an unsupported promise.

Polycarbonate Roofing Warranty: What to Check

"10-year warranty" is printed on almost every polycarbonate roofing quotation in India. It's also, by itself, close to meaningless. A warranty is only worth what its written terms actually cover — and most buyers never ask to see those terms until something has already gone wrong.

This post is a practical checklist for what a polycarbonate roofing warranty should specify, what it typically excludes, and the questions to ask before you sign a quotation — not after you notice yellowing three years in.

Why "10 Years" on Its Own Tells You Nothing

A warranty period without a defined performance threshold is just a number. The question that actually matters is: warranted against what, measured how, to what tolerance?

A properly written polycarbonate warranty should specify measurable performance criteria, not vague language like "will not deteriorate" or "long-lasting performance." Here's what a credible warranty document actually defines:

What a Real Warranty Should Cover

1. Light transmission retention

The warranty should state a minimum percentage of original light transmission (LT) the panel must retain by the end of the warranty period — for example, "retains at least 85% of initial light transmission at 10 years." Without this number, there's no objective way to determine whether the panel has failed the warranty or simply aged as expected.

2. Yellowness Index threshold

UV degradation shows up as yellowing before it shows up as anything else. A credible warranty references a maximum allowable Yellowness Index change, tested to ASTM E-313 or ASTM D1925, at defined intervals. We explain why this matters — and how yellowing actually progresses — in our UV ageing and long-term transparency guide.

3. Structural integrity / breakage

This covers cracking or structural failure under normal service conditions — explicitly excluding damage from events outside the material's rated performance (extreme impact, structural movement, fire, or acts of God, which are typically covered by building insurance, not a material warranty).

4. Co-extrusion delamination

The UV-protective layer should not peel, flake, or delaminate from the base polycarbonate for the life of the warranty. This is only meaningful if the UV layer is co-extruded (molecularly bonded during manufacturing) rather than surface-coated — a distinction we cover in our architect's specification checklist. Surface-applied UV coatings are not warrantable in the same way, because they are expected to wear over time by design.

What a Warranty Typically Does Not Cover — and Shouldn't

Read the exclusions section as carefully as the coverage section. Standard, reasonable exclusions include:

Installation defects not caused by the panel itself — incorrect fixing torque, wrong fastener type, inadequate purlin spacing. This is why the fixing system and installer matter as much as the panel; see our common installation mistakes guide.
Damage from incompatible cleaning agents — solvents, abrasives, or ammonia-based cleaners can strip UV protection and void coverage.
Extreme or unrated events — impact beyond the panel's tested class, structural movement, or fire.
Colour or batch variation within normal manufacturing tolerance.

These exclusions aren't red flags — they're standard and reasonable. The red flag is a warranty document that doesn't specify exclusions at all, because that usually means the coverage terms haven't been thought through either.

Product Warranty vs. System Warranty — Know Which One You're Getting

This distinction trips up a lot of buyers:

Product warranty covers the polycarbonate panel itself — LT retention, yellowing, delamination — as manufactured. It typically applies regardless of who installs it, though improper installation can void it.
System warranty covers the complete installed system — panel plus the fixing/dry-fix hardware plus workmanship — and is usually only offered when the installation is carried out or certified by an approved installer.

A system warranty is generally stronger for the buyer because it removes the "was it the panel or the installation" argument entirely. If a supplier only offers a product warranty, understand that a poorly executed installation — like the sealant-dependent details we discuss in our dry-fix vs sealant comparison — can cause failures the product warranty won't cover.

A Practical Warranty Checklist

Is there a defined LT retention percentage at a defined year mark? If not, ask for one in writing.
Is there a Yellowness Index threshold, and what test standard is it measured against?
Is the UV protection co-extruded, and does the warranty explicitly cover delamination?
Is this a product warranty or a system warranty — and does it require an approved installer?
What voids the warranty? Get the exclusions list, not just the headline coverage.
Is the warranty transferable if the building changes ownership within the warranty period? Relevant for commercial and industrial buyers.
Who assesses a claim, and against what documented baseline? Ask whether the manufacturer retains batch-level test data to compare against at claim time.

A warranty is a specification document, not a marketing line. If a supplier can't produce the measurable thresholds behind their "10-year" claim, ask them to put it in writing before you order — not after.

Longer Warranties Usually Track Real Quality Differences

This isn't a coincidence: panels with thicker co-extruded UV layers, tighter manufacturing tolerances, and full third-party test documentation can genuinely sustain longer warranty periods, because the manufacturer has the test data to back the claim. A supplier offering a long warranty with no test certificates behind it is making a promise they can't substantiate — while a supplier who can walk you through LT retention curves and Yellowness Index data at 5 and 10 years is one whose warranty is worth relying on.

Coxwell's warranty terms specify measurable LT retention and Yellowness Index thresholds, backed by NABL-accredited test data for every system we manufacture — Multicell, X-Fix, Prism, Snapwall, and Vivid. Ask our technical team for the full warranty document before you finalise your order.

What Should a Polycarbonate Roofing Warranty Actually Cover? A Buyer's Checklist