Why guarantees and warranties matter when hiring a builder
When you’re spending tens of thousands of dollars on a renovation, extension or repair, a builder’s promises should be more than a handshake. In New Zealand, the best protection is a combination of a clear written contract, a workmanship guarantee from the builder, warranties on products and materials, and your rights under the Consumer Guarantees Act 1993 (CGA).
A strong warranty setup won’t remove all risk, but it does make it much easier to sort out defects, delays and disagreements if something goes wrong. It also gives you a clearer picture of how professional the builder is. A builder who is vague about warranties, reluctant to put things in writing, or avoids discussing aftercare may be a warning sign.
Before you accept a quote, ask for multiple written quotes and compare more than just the total price. You should also check the builder’s credentials, such as whether they are a licensed building practitioner if the work requires one, and whether any specialist work will be carried out by the appropriate licensed tradesperson.
The main types of protection to look for
There are three different layers of protection homeowners should understand:
| Protection type | What it covers | Who is responsible | Typical source | |---|---|---|---| | Workmanship guarantee | Defects caused by the builder’s labour, installation or construction | The builder or their company | Written contract or warranty document | | Product warranty | Faulty materials, fittings or manufactured products | Product manufacturer or supplier, sometimes via the builder | Manufacturer’s warranty card, terms or invoice | | Consumer law rights | Services not carried out with reasonable care and skill, or not fit for purpose | The builder/service provider | Consumer Guarantees Act 1993 |
These layers overlap. For example, if a deck leaks because the builder installed flashing incorrectly, that is a workmanship issue. If a window seal fails because the window unit itself is defective, the product warranty may apply. If the builder promised a bathroom renovation that would suit your family’s needs and it clearly does not, the CGA may be relevant.
What a workmanship guarantee should cover
A workmanship guarantee is the builder’s promise that their labour and installation work will be free from defects for a stated period. In New Zealand, there is no universal minimum guarantee period for all building work, so the length and scope of the guarantee depends on the builder and the contract.
A useful workmanship guarantee should state:
- the exact period covered, such as 12 months, 24 months, or longer for certain structural elements - what is included, for example framing, cladding installation, joinery installation, tiling, waterproofing, and finishing work - what is excluded, such as normal wear and tear, damage caused by misuse, or later alterations by someone else - how defects are to be reported and the timeframe for the builder to inspect them - whether the builder will repair, replace, or reimburse at their discretion - whether subcontracted work is covered in the same way as the builder’s own work
For major residential work, many homeowners also expect a defects period after practical completion, during which minor issues such as sticking doors, shrinkage cracks, or paint touch-ups can be logged and fixed. That should not be confused with a long-term structural warranty.
Be wary of overly vague wording such as “guaranteed workmanship” without details. If it is not written down, it is much harder to enforce.
Product warranties: what they do and don’t do
A builder often supplies or installs products that already come with warranties from the manufacturer. Common examples include:
- windows and doors - roofing products - cladding systems - insulation - tapware and sanitaryware - appliances - water heaters - garage doors and hardware
Product warranties usually cover manufacturing faults, not damage caused by poor installation. That distinction matters. If a water feature, heat pump, or roof component fails because the product was faulty, the manufacturer’s warranty may help. If the same item fails because it was installed incorrectly, the builder may be responsible instead.
Homeowners should ask for:
- the product brand and model before the work starts, where practical - copies of warranty documents or links to warranty terms - confirmation of any conditions, such as regular servicing, correct cleaning products, or maintenance schedules - proof of purchase and installation records, because many warranties need these for a claim
If the builder is supplying products as part of the job, ask who is the actual warrantor. Sometimes the builder is simply the installer, while the product manufacturer stands behind the product. You want to know who to contact if a warranty claim is needed.
How the Consumer Guarantees Act applies to building work
The Consumer Guarantees Act 1993 gives homeowners important rights when they buy services from a trader, including builders. For building services, the builder must:
- carry out the work with reasonable care and skill - finish the work within a reasonable time, if no time is agreed - ensure the services are reasonably fit for the purpose you told them about - use materials that are of acceptable quality, where the builder supplies them
These rights apply even if a builder’s contract tries to limit them. A contract cannot simply wipe out your CGA rights for standard residential building work.
In practical terms, the CGA can help if the builder’s work is sloppy, incomplete, unsafe, or not what was agreed. It also matters if the builder gives advice that proves to be clearly unsuitable for your project.
That said, the CGA is not a guarantee of perfection. Minor cosmetic issues, fair wear and tear, and problems caused by the homeowner’s misuse or later alterations are usually not the builder’s responsibility.
Does the Building Act create a warranty?
The Building Act 2004 does not provide a simple blanket warranty for all residential building work, but it does set the framework for building consent, compliance and safe construction. If the job requires a building consent from the local council, the work must be carried out to meet the Building Code and the consented plans.
If a builder’s work is non-compliant, that can become a serious issue for insurance, resale and future alterations. It can also affect whether the council issues a Code Compliance Certificate once the job is complete.
For regulated work, make sure the right people are doing the right tasks:
- plumbing, gasfitting and drainlaying are restricted work regulated by the Plumbers, Gasfitters and Drainlayers Board (PGDB) - electrical work is regulated by the Electrical Workers Registration Board (EWRB) - building work may need a building consent from the local council, depending on the scope of the project
A builder who understands these boundaries is more likely to manage the job properly and coordinate the right licensed trades.
What to look for in a builder’s written warranty
Ask for the warranty terms before signing anything. A good warranty is specific, practical and easy to understand.
Look for:
- the legal name of the builder or company offering the warranty - the start date and expiry date - the exact address or project covered - what constitutes a defect - what evidence you need to provide, such as photos or a written description - how quickly the builder will respond to a claim - whether emergency call-outs are covered - whether labour, materials, travel and scaffolding are included in repairs - what happens if the builder has ceased trading
A useful warranty may also distinguish between:
- defects that are cosmetic and can be fixed later - defects that affect water-tightness, safety or structural performance and should be prioritised
If the builder offers a long warranty, check whether it is backed by insurance or simply by the builder’s promise. A warranty is only as strong as the business behind it.
Questions to ask before you sign
Use these questions when comparing builders:
- What workmanship guarantee do you provide, and for how long? - What exactly is covered, and what is excluded? - Are product warranties passed on to me in writing? - Who handles warranty claims if a subcontractor’s work fails? - Is any part of the work subject to a building consent or inspection by council? - Will you use licensed tradespeople for restricted work such as plumbing, gasfitting, drainlaying or electrical work? - How do you handle defects found after completion? - Can you provide contact details for recent clients with similar work?
If the answers are hesitant, vague or inconsistent with the quote, that is a sign to slow down.
What to do if the builder’s work is faulty
If you spot a problem, act quickly and document it well.
1. **Photograph the issue** from different angles, and note dates and times. 2. **Check the contract and warranty** to see whether the issue is covered. 3. **Notify the builder in writing** as soon as possible. Keep the message factual and specific. 4. **Give the builder a reasonable chance to inspect and fix it.** 5. **Keep records** of all emails, texts, invoices, and conversations.
If the builder does not resolve the problem, your options may include:
- asking for a written defect rectification plan - withholding payment only if the contract and circumstances allow it; get advice first, because withholding the wrong amount can create your own dispute - making a complaint to the relevant authority if the work involves licensing breaches, such as the PGDB or EWRB for restricted work - seeking independent advice from a building consultant, lawyer, or a dispute resolution service - applying to the Disputes Tribunal or the District Court, depending on the amount involved and the complexity of the dispute
For serious issues involving non-compliant building work, also contact the local council if a consented project is affected. If the work is unsafe or clearly unlawful, do not wait until the end of the job to raise it.
How to reduce warranty problems before the job starts
The best disputes are the ones you avoid. To protect yourself:
- get at least three written quotes - compare scope, materials, exclusions and warranties, not just price - insist on a written contract that names the builder’s legal entity - confirm who is responsible for council consent, inspections and code compliance paperwork - ask for evidence of licensing and insurance where relevant - keep a paper trail of any changes to the job, including variation pricing - agree on a defects process before work begins
It is also worth being realistic about NZ building conditions. Weather can affect timelines, especially in winter and in coastal or high-wind areas. A good builder should explain how rain, humidity, and seasonal delays may affect waterproofing, painting or exterior work, and whether those delays alter the warranty obligations.
The bottom line
A reliable builder should offer more than a verbal assurance. You want a clear workmanship guarantee, proper pass-through of product warranties, and a contract that sits comfortably with your rights under the Consumer Guarantees Act.
For New Zealand homeowners, the key is to know who is responsible for what: the builder for labour, the manufacturer for faulty products, and your statutory rights if the service itself is not carried out properly. If a builder is upfront about all three, puts everything in writing, and is willing to stand behind the work, that is a strong sign you are dealing with a professional.
When in doubt, slow down, compare multiple quotes, and check the paperwork before any deposit changes hands.