Building consents and council permits for waterproofing work in NZ

Why consents matter for waterproofing work

Waterproofing sits in a grey area for many homeowners because the work itself is often hidden, but the consequences of getting it wrong can be expensive. In New Zealand, whether you need a building consent or another council approval depends less on the trade label “waterproofer” and more on the type of work being done, where it is being done, and whether it affects the building’s structure, durability, or weathertightness.

A good waterproofer should be able to tell you when the job is likely to need consent, when it may be exempt, and when you should confirm details with your local council before work starts. For larger or more complex jobs, especially those tied into bathrooms, decks, balconies, basements, retaining walls, or changes to drainage, it is worth slowing down and checking first.

When waterproofing work usually needs a building consent

In New Zealand, building consent is generally required for building work unless it is specifically exempt under the Building Act 2004 and the Building (Building Work Exemptions) Regulations 2016. For waterproofing, consent commonly comes into play when the work is part of a wider building project or when it affects a building’s structure or external moisture protection.

Typical situations that often need consent include:

• New bathrooms, laundries or wet areas where the work forms part of a new build, major alteration, or change of use
• Substantial bathroom renovations if walls, flooring, plumbing layouts, floor levels, or waterproofing systems are being altered in a way that is not clearly exempt
• Balcony or deck repairs or rebuilds where the waterproofing is part of a structural repair, replacement of membrane layers, or changes to the deck build-up
• Below-ground waterproofing such as basement tanking, retaining wall waterproofing, or external membrane systems that are part of broader building work
• Repairs after leaks or damage if the work goes beyond minor maintenance and involves rebuilding parts of the building envelope
• Work that changes drainage or falls in a way that affects how water is managed on the property

If the waterproofing work is part of a larger alteration, the consent question is often about the whole project, not just the membrane itself.

Work that is often exempt

Some waterproofing-related jobs can be exempt, but exemption is not automatic. The work must fit the legal exemption and still be done to a professional standard.

Often-exempt situations may include:

• Like-for-like maintenance or repair of existing waterproofing, such as patching a small failed area without changing the overall system
• Minor internal repairs where the work does not affect structure, fire safety, sanitary facilities, or overall durability
• Replacement of bathroom sealants, grout, or localised membrane repairs when they are simple maintenance rather than a rebuild
• Small remedial works that restore an existing waterproofing system without changing the building layout or performance significantly

Be careful: many “repairs” are actually building work if they involve removing and replacing floor linings, shower trays, wall linings, or large membrane areas. If a contractor says, “It’s just a repair, no consent needed,” ask them to explain why and whether they have checked against the exemptions.

A useful rule of thumb is this: if the job involves opening up the substrate, rebuilding wet-area linings, changing the shower base, altering a deck structure, or affecting external water ingress protection, you should assume consent may be required until confirmed otherwise.

Waterproofer work that may sit alongside other regulated trades

Waterproofing projects often include other trades, and that can trigger extra compliance requirements.

• Plumbing, gasfitting and drainlaying are restricted building work under the Plumbers, Gasfitters and Drainlayers Act and must be carried out by licensed practitioners where required.
• Electrical work in wet areas must be done by a licensed electrician or electrical worker authorised under the Electrical Workers Registration Board.
• Tiling itself is not a licensed trade in NZ, but the substrate, falls, membranes and penetrations must still meet the Building Code.

If your waterproofer is coordinating with other trades, make sure each one is properly licensed for their own work. A compliant membrane job can still fail if plumbing penetrations, shower fittings, or floor falls are not done correctly.

Council permits and other approvals beyond building consent

Sometimes homeowners use “permit” as a catch-all, but in New Zealand there can be several approvals involved.

If the waterproofing is on a balcony, deck, retaining wall, or basement near a boundary, resource consent or planning checks can sometimes matter too. This is more likely where the work changes site drainage, land levels, or visible external elements.

The process: how to check whether you need consent

Before hiring a waterproofer, follow a simple process.

1. Define the scope clearly

Ask yourself:

• Is this maintenance, repair, or a full replacement?
• Are you changing the layout, substrate, or floor levels?
• Are any plumbing fixtures, traps, or wastes being moved?
• Is it inside a bathroom, outside on a deck, or below ground?
• Will anyone need to remove linings, concrete, tiles, or structural elements?

The more invasive the job, the more likely consent is needed.

2. Ask the waterproofer for a written scope

A professional quote should spell out:

• what surfaces will be prepared
• what membrane system will be used
• whether the work is internal, external, or below ground
• who is responsible for falls, detailing, and penetrations
• whether they believe the job is exempt or requires consent

If they believe it is exempt, ask them to note the reason in writing.

3. Check with the council early

Your local council building team can often tell you whether the work appears consented, exempt, or likely to need more information. This is especially useful if the job is a bit unusual, such as:

• a tiled shower replacement in an older home
• waterproofing over a concrete slab with damp issues
• a balcony membrane replacement in an apartment complex
• a basement conversion or tanking project

You do not need to wait until the day before work starts. A quick early enquiry can save weeks of delay.

4. Get the right paperwork before work begins

If consent is required, make sure the documentation is lined up before the first tile comes off. Depending on the project, that may include:

• plans or drawings
• product data sheets for the membrane system
• producer statements or manufacturer installation instructions
• inspection stages agreed with council
• details for any plumbing or electrical work

For complicated jobs, having all of this in place helps avoid hold-ups and costly rework.

What councils look for on waterproofing jobs

Councils are mainly concerned with whether the completed work complies with the Building Code. For waterproofing, the big issues are usually:

• durability of the membrane and supporting materials
• moisture management around wet areas and external surfaces
• falls to drains in showers, decks, and balconies where applicable
• detailing at corners, penetrations, upstands and junctions
• compatibility of products used together
• installation instructions being followed properly

In practice, this means a membrane that is technically good on paper can still fail if the substrate is not prepared correctly or if the installer ignores the manufacturer’s system.

The risks of skipping consent

Skipping consent can be tempting, especially if you are trying to keep costs down or avoid delays. But in NZ the downside can be significant.

Possible risks include:

• Council enforcement action if work should have been consented
• Difficulty selling the property if records are incomplete or work is questioned by a buyer’s lawyer or inspector
• No Code Compliance Certificate for work that needed one
• Insurance disputes if a later leak or failure is linked to unconsented work
• Expensive remediation if the job has to be opened up and redone
• Liability issues if the work causes damage to adjacent units, neighbouring properties, or the structure itself

Waterproofing failures are especially painful because the damage is often hidden. A small leak can lead to mould, rotten framing, damaged plasterboard, and flooring replacement long after the original job looked finished.

How to protect yourself when hiring a waterproofer

To reduce consent and compliance problems, do the basics well:

• get at least two or three written quotes for comparison
• check whether the contractor has experience with the exact type of job
• ask for the membrane product name and installation system
• confirm who will organise inspections if consent is required
• check licensing or trade credentials for any plumbing, gasfitting, drainlaying, or electrical work involved
• ask for references or examples of similar NZ jobs, especially for balconies, bathrooms, and wet areas

If a quote is much cheaper than the others, find out why. It may exclude prep work, council interaction, or remedial detailing that you will later have to pay for separately.

Seasonal and practical timing tips

In many parts of New Zealand, waterproofing work is easier to schedule in the drier months, especially for external decks, balconies, and below-ground sealing. Winter rain and humidity can slow curing and make leak testing harder, while summer demand can push prices up and stretch lead times.

If the job is internal, you still need to think about drying time, ventilation, and how long parts of the house will be unusable. Bathrooms and laundries often need planning around family schedules, especially if there is only one shower in the house.

A sensible rule before you start

If the job is more than a minor patch, ask two questions before hiring:

1. Does this need building consent, a resource consent, or neither?
2. If it is exempt, can the contractor explain why and what standard they will still build to?

That simple check can save you from compliance problems, insurance headaches, and costly rework later. For anything involving a full wet-area rebuild, deck or balcony membrane, basement waterproofing, or work tied to plumbing changes, it is worth getting advice early and keeping a clear paper trail from the start.