How to Check a Waterproofer Is Qualified and Licensed in New Zealand

Why checking a waterproofer matters

Waterproofing failures are expensive in New Zealand. A leaking shower, balcony, or basement can lead to damaged framing, mould, rotten linings, and insurance headaches — and in many cases the fix costs far more than doing the job properly first time. In our damp climate, especially through winter and in coastal areas, a good waterproofing system is not a nice-to-have. It is essential.

The tricky part is that “waterproofer” is not always a single, separately licensed trade in NZ. Depending on the job, the person doing the work may need specialist product training, a building practitioner licence, or to work alongside other licensed trades such as a plumber or builder. So when you are hiring, you need to check the right credentials for the actual job, not just assume a business card is enough.

Know what type of work your project involves

Before you check qualifications, work out exactly what the waterproofer will be doing. The required credentials can change depending on the location and scope of the work.

Common waterproofing jobs include:

• Tiling membranes in bathrooms, showers, and laundries
• Balcony and deck waterproofing
• Basement or foundation waterproofing
• Roof and planter-box membrane work
• Tanking and damp-proofing below ground
• Waterproofing around penetrations, waste pipes, and upstands

That matters because different parts of the job may overlap with other regulated trades or consent requirements. For example:

• If the job involves plumbing fixtures or pipe penetrations, a plumber may need to be involved.
• If the waterproofing is part of building work, the builder or installer may need to be a Licensed Building Practitioner (LBP) for the relevant work.
• If the work changes structural elements or forms part of a consented renovation, your council may require building consent.

Is waterproofing a licensed trade in NZ?

There is no single national “waterproofer licence” that covers every waterproofing job. Instead, the key checks in New Zealand are usually:

• Licensed Building Practitioner (LBP) status, if the work falls under restricted building work
• Manufacturer or industry certification, especially for membrane systems and product-specific installation standards
• Relevant trade qualifications and experience, such as tiling, building, or specialist membrane installation training
• Council consent and compliance knowledge, where the work forms part of a building consented project

In short: a waterproofer may be highly skilled without holding a stand-alone trade licence labelled “waterproofer”, but they still need to be properly qualified for the job they are doing.

Check whether the work is restricted building work

Under New Zealand building rules, some residential work is classed as restricted building work (RBW) and must be carried out or supervised by an LBP. Waterproofing can be part of RBW when it is part of the building envelope or wet-area work that affects weathertightness or structural compliance.

This is especially relevant for:

• Internal wet areas in homes, such as showers and bathrooms
• Membranes on decks and balconies that form part of the building structure or envelope
• Work affecting external moisture control or weathertightness

If the project is RBW, ask the contractor directly:

• Are you an LBP for this type of work?
• What licence class do you hold?
• Will you personally do the work, or will it be supervised by an LBP?
• Will you provide the Record of Work if required?

An LBP should be able to explain how their licence relates to the waterproofing project. If they cannot, that is a warning sign.

How to verify an LBP licence

The easiest official check is the Licensed Building Practitioners Register. You can search by the contractor’s name or company and confirm:

• Their current LBP status
• Licence class
• Whether the licence is active
• Any public disciplinary information, where available

When checking the register, make sure the name on the register matches the person who will actually do or supervise the work. A company can employ multiple people, and one licensed person does not automatically cover everyone.

Ask for:

• Full name as it appears on the register
• LBP number
• Licence class relevant to the job
• Proof that their licence is current

If the project involves restricted work and they are not an LBP, ask how they intend to comply. Do not rely on vague assurances.

Look for product and system certification

A good waterproofer should not just know how to roll on a membrane. They should know the specific system they are installing and follow the manufacturer’s instructions exactly.

Useful things to check include:

• Product-specific training for the membrane or waterproofing system being used
• Approved applicator status, where the manufacturer offers one
• System warranties, including whether they are available only when installed by approved installers
• Compliance documentation, such as technical datasheets and installation requirements

This matters because many waterproofing failures come from incorrect surface prep, poor detailing around corners and drains, or using a product outside its approved application.

If the installer says they use a “similar product” or “their own method”, ask them to explain:

• What exact product/system they will use
• Why it is suitable for your substrate and location
• Whether it is suitable for internal or external use
• How it will be detailed at junctions, penetrations, and terminations

A reputable tradesperson should be happy to show you the technical information before work starts.

Ask about relevant qualifications and experience

Not every competent waterproofer will have the same background, but they should be able to show training and recent experience relevant to your job.

Useful qualifications or backgrounds may include:

• Building or carpentry qualifications
• Tiling qualifications
• Specialist waterproofing or membrane installation training
• Industry courses from recognised NZ training providers or product manufacturers

Experience matters just as much as certificates. A contractor who mostly does shower membranes may not be the best choice for a basement tanking job, and vice versa.

Ask:

• How long have you been waterproofing in NZ?
• What similar jobs have you done recently?
• Have you worked with this exact system before?
• Can you provide recent references or photos of completed work?

Check insurance and workmanship guarantees

Qualifications are important, but so is protection if something goes wrong.

Before hiring, ask whether they have:

• Public liability insurance
• Contract works insurance, if relevant
• A written workmanship warranty
• Clarity on whether the product warranty is separate from the labour warranty

Be careful with warranties that sound impressive but only apply if the installer followed the manufacturer’s system exactly. If the work is not documented properly, a warranty claim can become difficult.

Ask for everything in writing, including:

• Scope of work
• Products to be used
• Prep and curing times
• Warranty length and conditions
• What is excluded

Compare quotes and credentials side by side

Get at least two or three written quotes. For waterproofing, the cheapest quote is not necessarily the safest.

When comparing quotes, look at whether each one clearly states:

If one quote is much lower, find out why. It may exclude prep work, specify a cheaper system, or omit compliance steps that should not be skipped.

Check council consent and documentation needs

Some waterproofing work is part of a larger building project and may require building consent from your local council. This is common when the work is part of an alteration, extension, or major bathroom renovation.

Ask your contractor:

• Does this job need building consent?
• Will you prepare the documents needed for the council or my builder?
• Will you provide producer statements, warranties, or installation certificates if required?
• Do I need to keep records for future inspections or a Code Compliance Certificate?

If you are renovating a bathroom, for example, consent requirements may depend on whether walls are being altered, whether plumbing is moved, and how the wet area is constructed. It is worth confirming before work starts, because fixing a compliance issue later is far more expensive.

Red flags to watch for

A genuinely qualified waterproofer should be straightforward about their credentials and process. Be cautious if they:

• Refuse to provide a full name, licence number, or references
• Say licensing does not matter for waterproofing at all
• Cannot explain which membrane system they use
• Promise to start immediately but do not mention prep, drying, or curing times
• Offer a cash-only price with no written quote
• Won’t discuss warranty terms or insurance
• Suggest skipping consent or documentation where it may be needed

If the contractor becomes defensive when you ask for proof, that is usually information in itself.

A practical checklist before you hire

Use this quick checklist before signing anything:

• Confirm whether the job is restricted building work
• Check the LBP Register if applicable
• Ask for the exact product system and installation method
• Confirm relevant experience with your type of project
• Request written quotes from at least two or three tradespeople
• Check insurance and workmanship warranties
• Ask whether building consent or council documentation is needed
• Keep copies of quotes, invoices, product sheets, and photos

Why this matters in New Zealand homes

New Zealand’s housing stock includes many homes that are older, altered over time, or built in exposed coastal and high-rainfall areas. Water gets in through the smallest weakness, and once it does, the repair is often disruptive.

Hiring a properly qualified waterproofer gives you a much better chance of:

• Passing inspections or compliance checks
• Protecting your home from hidden moisture damage
• Preserving warranty and insurance cover
• Avoiding repeated repairs after a failed membrane

In a wet climate, good waterproofing is not just a finish detail. It is part of the home’s long-term durability.

Final advice

When you hire a waterproofer in NZ, do not just ask, “Can you do the job?” Ask, “What qualifications, licence status, product training, and compliance documents can you show me?”

The best contractors will answer clearly, provide written proof, and welcome comparison quotes. That is the safest way to separate a real professional from someone who is simply cheap.