Roofing warranties come in three flavors: manufacturer (covers defective shingles, typically 25-50 years prorated), workmanship (covers installation errors, typically 1-25 years from the contractor), and extended system warranty (covers both, requires certified installer, typically 25-50 years non-prorated). This article explains what each actually covers, what voids them (improper ventilation is the #1 voider), and what questions to ask before signing a roofing contract.
There are two warranties on a new roof and they cover different things. The manufacturer warrants the material against defects. The contractor warrants the installation. Most roof failures are installation, which is why the second one is the one to read.
| Manufacturer material warranty | Contractor workmanship warranty | |
|---|---|---|
| Covers | Defects in the shingle itself | Errors in how it was fitted |
| Typical term | 25 years to lifetime, usually prorated | 1 to 10 years, sometimes longer |
| Who honours it | The manufacturer | The contractor, if still trading |
| Common exclusions | Improper installation, inadequate ventilation, foot traffic | Storm damage, neglect, later work by others |
| What voids it | Wrong fasteners, wrong nailing, poor ventilation, a second layer | Repairs or alterations by someone else |
The signed contract, the itemised quote, the permit and final inspection, photographs of the deck before it was covered, the material lot numbers, and both warranty documents. A claim years later stands or falls on that folder, and photographs of bad decking that was replaced are the ones people most wish they had taken.
The manufacturer warrants the shingle against defects; the contractor warrants how it was fitted. Most roof failures are installation, which makes the workmanship warranty the one to read closely.
It generally means the life of the original owner, not the roof, and it is usually prorated after an initial full-coverage period — after a decade the payout can be a small fraction of the material cost.
Inadequate attic ventilation most commonly, then staples or the wrong nailing pattern, installing over an existing layer where a tear-off is required, mixing manufacturers under a system warranty, and pressure washing the roof.
Often once, within a set window after installation, and sometimes for a fee. It matters at resale, so check the terms and keep the paperwork.