When hiring a roofer in New Zealand, you should expect two distinct types of warranty: one covering the roofer's workmanship (labour) and another covering the roofing materials themselves. Understanding the difference — and knowing what's reasonable to ask for — can save you significant stress and money down the track.
Workmanship Warranties: What's Reasonable?
A workmanship warranty (sometimes called a labour warranty) covers defects caused by how the roof was installed — things like poor flashing, incorrect fixings, or inadequate sealing. This is the roofer's personal guarantee that the job was done properly.
In New Zealand, there is no single legislated minimum period for roofing workmanship warranties, but industry norms are:
- Residential re-roofing or new roofs: 5–10 years is considered standard for quality contractors
- Repairs and minor works: 1–2 years is common, though some roofers offer more
- Commercial roofing: Often 10+ years, negotiated as part of the contract
Always get the workmanship warranty in writing as part of your contract. A verbal promise is very difficult to enforce. Under the Consumer Guarantees Act 1993, work must be carried out with reasonable care and skill — this is a baseline legal protection regardless of what's written in the contract, but a written warranty makes any claim far easier to pursue.
Materials Warranties: Manufacturer vs Installer
The materials warranty comes from the product manufacturer, not the roofer. It covers defects in the product itself — such as premature coating failure, cracking, or corrosion under normal conditions.
Typical manufacturer warranty periods for common NZ roofing materials:
| Material | Typical Manufacturer Warranty |
|---|---|
| Long-run steel (e.g. Colorsteel) | 10–30 years (varies by product grade) |
| Concrete or clay tiles | 15–50 years |
| Asphalt shingles | 20–30 years |
| Membrane (TPO/PVC flat roofing) | 10–20 years |
| Butyl or modified bitumen | 10–15 years |
These figures are a general guide — always check the specific product datasheet. Note that many manufacturer warranties are conditional: they may require the product to be installed by an approved installer, using compatible accessories, and in accordance with the manufacturer's technical instructions. If your roofer doesn't follow those requirements, the manufacturer's warranty can be voided.
Approved Installer Programmes
Some manufacturers run approved or accredited installer programmes that unlock extended warranties. For example, certain steel roofing suppliers offer extended system warranties (sometimes 15–30 years on the full roof system) when an approved contractor installs their product correctly. Ask your roofer whether they hold any such accreditations and whether the extended warranty applies to your job.
BRANZ provides independent research and appraisals on roofing products — a BRANZ Appraisal on a product is a good sign that it has been independently assessed for NZ conditions.
What the NZ Building Code Requires
All roofing work must comply with the NZ Building Code, particularly Clause E2 (External Moisture), which sets performance requirements for keeping weather out. Whether your project needs a building consent depends on the scope of work — a full re-roof on a residential dwelling may be exempt under Schedule 1 of the Building Act, but this isn't always the case. Always check with your local council before starting significant roofing work.
Where a building consent is issued, the council will inspect the work and issue a Code Compliance Certificate (CCC) on completion. This is separate from any warranty but provides an important record that the work met the Building Code at the time.
What to Ask Your Roofer Before Signing
Before agreeing to any roofing contract, ask these questions:
- What is your workmanship warranty period, and is it in writing?
- What materials are you using, and what is the manufacturer's warranty?
- Are you an approved installer for those materials?
- Does the warranty transfer if I sell the house?
- What voids the warranty (e.g. modifications, foot traffic, other trades)?
- Are you a Licensed Building Practitioner (LBP)?
That last point matters. Under the Building Act, certain restricted building work — including work on the roof of a house that affects weathertightness — must be carried out or supervised by a Licensed Building Practitioner. Hiring an LBP also gives you access to the LBP complaints process if something goes wrong.
When to Call a Professional
All significant roofing work on a residential dwelling should be carried out by a qualified, experienced roofer — ideally an LBP. Roof failures are one of the leading causes of weathertightness damage in NZ homes, and poor workmanship can lead to costly structural repairs. If you're unsure whether a roofer's warranty offer is reasonable, get two or three quotes and compare what each contractor is offering in writing.
You can find qualified local roofers on tradedirectory.co.nz. Always ask to see their LBP licence number and check it on the LBP register before work begins.
Roofing Association of NZ (RANZ)
Licensed Building Practitioner (LBP)
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