How Do I Know If a Waterproofer Is Using Compliant Products in NZ?

Knowing whether your waterproofer is using compliant products comes down to asking the right questions, understanding what the NZ Building Code requires, and checking that the products and systems used have appropriate technical documentation. A reputable waterproofer will be transparent about the products they use and happy to provide evidence of compliance — if they're not, that's a red flag worth taking seriously.

Why Product Compliance Matters

Waterproofing is a critical part of any building. Failures can lead to moisture damage, structural rot, mould, and costly remediation work. In New Zealand, waterproofing must meet the requirements of the NZ Building Code, particularly Clause E3 (Internal Moisture) and Clause E2 (External Moisture). These clauses set performance standards for keeping water out of areas like wet rooms, decks, and balconies. Products and systems used must be fit for purpose and demonstrably meet those standards.

The MBIE Building Performance website is the best starting point for understanding what the Building Code requires and how compliance can be demonstrated.

What Makes a Waterproofing Product "Compliant"?

In NZ, there are two main pathways a product or system can use to demonstrate Building Code compliance:

• Acceptable Solutions – Products that meet a prescribed solution outlined in documents like E2/AS1 or E3/AS1. These are pre-approved methods.
• Alternative Solutions – Products that achieve the Building Code performance requirements through another means, such as a CodeMark certificate, a BRANZ Appraisal, or a specific engineer's assessment.

A CodeMark certificate is a product certification scheme recognised under the Building Act 2004. A BRANZ Appraisal is an independent technical assessment carried out by BRANZ, New Zealand's building research organisation. Both are strong indicators that a product has been independently evaluated for NZ conditions.

Questions to Ask Your Waterproofer

Before work starts, ask your waterproofer these key questions:

• What specific products and systems will you use? Get brand names and product names in writing.
• Do these products have a CodeMark certificate or BRANZ Appraisal? Ask to see the documentation.
• Are you applying the product strictly to the manufacturer's specifications? Compliance often depends on correct installation — thickness, priming, detailing at junctions, and curing times all matter.
• What warranty does the product carry, and does it require a licensed applicator? Some manufacturers only honour warranties when their product is applied by a trained or licensed installer.
• Will you provide a producer statement or written confirmation of compliance? This is especially important if a building consent is involved.

How to Verify Products Yourself

You don't have to take your waterproofer's word for it. Here's how to do your own checks:

Well-known waterproofing brands available in NZ include Ardex, Mapei, and Sika, all of which publish detailed technical data sheets and have products with recognised compliance pathways. If your waterproofer is using a product you've never heard of and can't provide documentation for, ask more questions.

Building Consents and Inspections

Many waterproofing jobs — particularly wet areas in new builds or significant renovations — will require a building consent. If a consent is required, the products and systems used must be documented as part of the consent application. Your local council's building inspector will check that the work meets the consented specifications.

Some minor waterproofing repairs may fall under Schedule 1 exemptions of the Building Act, meaning no consent is needed — but always confirm this with your local council before assuming work is exempt. You can find general guidance on consents at MBIE Building Performance.

Manufacturer Specifications Must Be Followed

Even a fully compliant product can fail if it's not installed correctly. Compliance isn't just about the product — it's about the system, including:

• Correct surface preparation
• Appropriate primer (if required)
• Minimum wet film thickness or number of coats
• Correct detailing at corners, penetrations, and junctions
• Adequate curing time before tiling or covering

Ask your waterproofer to confirm they are following the manufacturer's installation instructions to the letter. A good waterproofer will have no hesitation showing you the technical data sheet on site.

When to Call a Professional

Waterproofing in wet areas (bathrooms, laundries, balconies, and decks) is not a DIY job in most cases — particularly where a building consent is involved or where the work is part of a larger construction project. While waterproofing itself is not classified as restricted building work under the Licensed Building Practitioners scheme, many related tasks (such as structural work or plumbing) are. You can check what constitutes restricted work at Licensed Building Practitioners.

For peace of mind, hire a qualified waterproofer who can demonstrate product knowledge, provide compliance documentation, and back their work with a warranty. You can find experienced local waterproofing professionals on tradedirectory.co.nz.

Sources & Further Reading

• MBIE Building Performance – NZ Building Code
• BRANZ – Building Research and Appraisals
• Ardex NZ – Waterproofing Systems
• Mapei NZ – Waterproofing Products
• Sika NZ – Construction Products
• Licensed Building Practitioners