A professional renderer in New Zealand should provide a written warranty covering both workmanship and materials, typically ranging from two to ten years depending on the system used and the contractor's own guarantee policy. While there is no single mandatory warranty period set specifically for rendering work, you do have strong protections under NZ consumer law and the Building Code — and knowing what to ask for upfront can save you a lot of grief later.
What a Renderer's Warranty Should Cover
A solid warranty from a professional renderer should clearly spell out:
- Workmanship: Protection against defects caused by poor application technique, incorrect mixing ratios, or inadequate surface preparation.
- Materials: Confirmation that the products used meet manufacturer specifications and are fit for purpose in your specific climate and substrate.
- Cracking and delamination: These are the most common rendering failures. A good warranty should address what counts as acceptable hairline cracking versus defective cracking.
- Weatherproofing performance: Particularly important for exterior render, which must comply with NZ Building Code Clause E2 (External Moisture). If render fails to keep water out, that's a serious defect.
- Remediation process: The warranty should state clearly how a claim is made, who carries out repairs, and within what timeframe.
Typical Warranty Periods in NZ
Warranty lengths vary depending on the render system and the contractor:
| Render Type | Typical Workmanship Warranty | Manufacturer Product Warranty |
|---|---|---|
| Cement-based render | 2–5 years | Varies by brand |
| Acrylic texture coat systems | 5–10 years | Often 10–15 years (system-specific) |
| Fibre-cement substrate systems | 5–10 years | Check with manufacturer |
| Polystyrene cladding systems (EPS) | 5–10 years | System-dependent |
Note that manufacturer warranties on products like acrylic coatings are separate from the tradesperson's workmanship warranty. Always ask for both in writing.
Your Rights Under NZ Consumer Law
Even if a renderer doesn't offer a formal written warranty, you are protected under the Consumer Guarantees Act 1993 (CGA). Under the CGA, services must be carried out with reasonable care and skill, and the result must be fit for purpose. If the work fails within a reasonable time, the tradesperson is obliged to remedy it at no cost to you.
For more guidance on your consumer rights, Consumer NZ is an excellent resource. You can also check MBIE Building Performance for information on how the Building Code applies to cladding and render systems.
What to Ask Before Signing a Contract
Before any rendering work begins, ask your renderer these questions:
- Is the warranty written into the contract? Verbal promises are hard to enforce.
- What products are being used, and do they carry a manufacturer's warranty?
- Is the renderer applying the product as a licensed or approved applicator? Some manufacturers (particularly for proprietary systems) only honour warranties when applied by approved contractors.
- What surface preparation is included? Most render failures start with poor prep — cracks, contamination, or insufficient bonding. A warranty that excludes prep-related failures is worth very little.
- Does the warranty transfer if you sell the property? This can add real value at sale time.
The Role of the NZ Building Code
Exterior render must comply with NZ Building Code Clause E2 (External Moisture) to ensure the building envelope keeps water out. If a building consent was required for your project (for example, new cladding on a new build or significant recladding work), the renderer's work must meet these standards. Always check with your local council whether a building consent is required — some recladding work may qualify as a Schedule 1 exemption, but this is not always the case.
BRANZ publishes technical guidance on render systems and weathertightness that both homeowners and tradespeople can reference.
Red Flags to Watch Out For
- A renderer who refuses to provide anything in writing
- Warranties that exclude cracking entirely (some cracking is normal, but delamination and wide cracking should be covered)
- No mention of which specific products will be used
- Pressure to start immediately without a signed contract
- No evidence of previous work or references
When to Call a Professional
Rendering is skilled trade work. While a homeowner might patch a small area of interior render, exterior rendering — especially on multi-storey buildings or as part of a weathertight cladding system — should always be carried out by an experienced professional. Poorly applied render can lead to moisture ingress, which is one of the most costly building defects in New Zealand.
If your home has a Licensed Building Practitioner (LBP) requirement for the work (for example, restricted building work related to the primary structure or weathertightness), the renderer or supervising tradesperson must hold the appropriate LBP licence. Check the Licensed Building Practitioners register to verify credentials.
You can find qualified, experienced renderers in your area right here on tradedirectory.co.nz.
Licensed Building Practitioner (LBP)
