Can a Tiler Legally Do Waterproofing Work in New Zealand?

Yes, in New Zealand a tiler can legally carry out waterproofing work — and in most cases, waterproofing and tiling go hand in hand. However, the legality and compliance of that work depends on where it's being done, whether a building consent is required, and whether the work meets the New Zealand Building Code. Here's what every homeowner should know.

What Does Waterproofing Work Actually Involve?

In a tiling context, waterproofing typically means applying a membrane or liquid-applied system to wet areas such as showers, bathrooms, laundries, and balconies before tiles are laid. The goal is to prevent water from penetrating the substrate and causing damage to the building structure.

Common waterproofing products used by NZ tilers include membrane systems from brands like Ardex, Mapei, and Sika. These are applied to floors, walls, and junctions before tiling begins.

The NZ Building Code and Wet Area Requirements

Waterproofing in wet areas is governed by the NZ Building Code, specifically Clause E3 (Internal Moisture). This clause requires that internal wet areas are constructed so that moisture doesn't damage the building or create unhealthy conditions.

For a tiler's work to be compliant, the waterproofing system must:

• Be installed according to the product manufacturer's specifications
• Meet the performance requirements of Clause E3
• Use products that have been assessed and approved (many carry a CodeMark certificate or are covered by an BRANZ Appraisal)

BRANZ provides technical guidance on wet area construction and waterproofing systems that are widely referenced by tradespeople and councils across New Zealand.

Does Waterproofing Require a Building Consent?

This is where things get nuanced. Many standard bathroom or shower waterproofing and tiling jobs fall under Schedule 1 of the Building Act, which lists work exempt from building consent. However, exemptions have conditions, and not all waterproofing work qualifies.

As a general guide:

• Replacing tiles and waterproofing in an existing shower or bathroom is often exempt
• New wet areas, significant alterations, or work on balconies and decks may require consent
• Work on multi-unit dwellings or commercial buildings may have different requirements

Always check with your local council before starting work, as consent requirements can vary and the consequences of non-compliant work can be significant. You can find more information at MBIE Building Performance.

Is Waterproofing Restricted Work?

Unlike plumbing, gasfitting, or electrical work — which are legally restricted trades requiring a licensed practitioner under the Plumbers Gasfitters & Drainlayers Board or Electrical Workers Registration Board — waterproofing membrane application is not a restricted trade in New Zealand.

This means a tiler (or even a competent homeowner, in some cases) can legally apply waterproofing membranes. However, competence and correct application matter enormously. A poorly applied membrane is one of the most common causes of costly water damage in NZ homes.

What Makes a Good Tiler for Waterproofing?

While waterproofing isn't legally restricted, you should look for a tiler who:

• Has proven experience with wet area waterproofing systems
• Is familiar with the specific products they're using and follows manufacturer application guides
• Understands NZ Building Code Clause E3 requirements
• Can provide documentation of the waterproofing system used (useful if you ever sell the home)
• Holds a Licensed Building Practitioner (LBP) licence — while not mandatory for all tiling work, an LBP can carry out and sign off on restricted building work where applicable

Healthy Homes and Rental Properties

If you're a landlord, note that the Healthy Homes Standards include moisture and drainage requirements. Ensuring wet areas are properly waterproofed and tiled is part of maintaining a compliant, healthy rental property.

When to Call a Professional

While a skilled tiler can legally handle waterproofing, you should always engage a qualified professional for this work. Waterproofing failures are expensive to fix — often requiring full tile removal and substrate repair. A professional tiler will:

• Select the right membrane system for your substrate and conditions
• Apply it correctly, including critical junctions and penetrations
• Ensure the work meets Building Code requirements

If the job involves new drainage, waste pipes, or any plumbing connections, those elements must be carried out by a licensed plumber or drainlayer — waterproofing and tiling around them is fine, but the plumbing itself is restricted work.

You can find qualified, experienced local tilers on tradedirectory.co.nz.

Sources & Further Reading

• MBIE Building Performance – Building Code Clause E3
• BRANZ – Wet Area Construction Guidance
• Licensed Building Practitioners – LBP Scheme
• Ardex NZ – Waterproofing Systems
• Sika NZ – Waterproofing Products
• Tenancy Services – Healthy Homes Standards