What Information Should Be Included in a Waterproofing Quote?

A detailed, well-structured waterproofing quote is your best protection against budget blowouts, substandard work, and disputes down the track. In New Zealand, waterproofing is a critical part of the building envelope — getting it wrong can lead to costly moisture damage, failed building inspections, and even health issues from mould. Before you accept any quote, here's what it should contain.

Full Business and Licence Details

The quote should clearly show the contractor's full legal business name, physical address, phone number, and email. Ask whether the tradesperson holds a current licence or registration relevant to the work. While waterproofing itself is not a licensed trade in the same way as electrical or plumbing, many waterproofing jobs are tied to restricted building work under the NZ Building Code — for example, waterproofing that forms part of the weathertight envelope of a house. In those cases, the work must be carried out or supervised by a Licensed Building Practitioner (LBP). The quote should state the LBP licence number and class if applicable.

Scope of Work — In Plain Language

This is the heart of any quote. A vague scope is a red flag. The quote should describe:

• Exactly which areas are being waterproofed (e.g., shower floor and walls to 1800 mm, balcony deck, wet room, retaining wall, basement slab)
• Surface preparation required — grinding, priming, crack repair, or removal of existing failed membranes
• Number of coats to be applied and the method (brush, roller, trowel, spray)
• Cove and fillet details at floor-to-wall junctions (critical for shower and wet area compliance)
• Flashings, upstands, and penetration sealing around pipes, drains, and fixings
• Any associated work such as tiling, drainage installation, or substrate repairs

Specific Products and Materials

The quote must name the exact waterproofing system to be used — brand, product name, and ideally the product data sheet reference. Well-known systems used in NZ include products from Ardex, Mapei, and Sika. Knowing the product lets you verify it is appropriate for the substrate and location, and check that it complies with NZS 4858:2004 (the standard for wet area membranes in NZ) or other relevant standards.

Also check:

• Is the product suitable for the specific substrate (concrete, fibre cement, timber frame)?
• Is it rated for internal wet areas, external decks, or below-ground use?
• What is the minimum dry film thickness (DFT) specified?

Compliance with the NZ Building Code

Waterproofing in wet areas must meet NZ Building Code Clause E3 (Internal Moisture). For external applications such as decks and balconies, Clause E2 (External Moisture) also applies. The quote should reference which code clauses and acceptable solutions are being followed. If the job requires a building consent, this must be stated — always confirm consent requirements with your local council, as requirements vary. Some minor waterproofing repairs may fall under Schedule 1 exemptions, but don't assume — check first.

For guidance on moisture and weathertightness requirements, BRANZ and MBIE Building Performance are excellent resources.

Pricing Breakdown

A professional quote should itemise costs clearly, including:

As a rough guide, waterproofing costs in NZ vary widely depending on area size, product system, and access — always get at least two or three quotes to compare. Be cautious of quotes that are unusually cheap, as cutting corners on waterproofing can be extremely expensive to fix later.

Warranty and Guarantee Information

This section is non-negotiable. The quote (or accompanying terms) should specify:

• Workmanship warranty — how long the contractor guarantees their labour (commonly 5–10 years for quality operators)
• Product warranty — the manufacturer's warranty on the membrane system itself
• Any conditions that could void the warranty (e.g., substrate movement, incorrect tiling adhesive used over the membrane)

Note that under the Consumer Guarantees Act, services must be carried out with reasonable care and skill regardless of what a written warranty says.

Timeline and Programme

The quote should include:

• Start date and estimated completion date
• Cure times between coats and before tiling or foot traffic (waterproofing membranes often need 24–72 hours between coats)
• Any weather or temperature conditions that could affect the programme (important for outdoor work in NZ's variable climate)

Payment Terms

Look for clearly stated payment milestones — for example, a deposit on acceptance, progress payment on completion of membrane, and final payment after inspection. Be wary of contractors asking for large upfront payments. Payment terms should also reference what happens if variations to scope are required.

When to Call a Professional

Waterproofing that forms part of the weathertight envelope of a home — such as deck membranes, balcony flashings, or shower liners in a new build or renovation — is often restricted building work requiring an LBP. Even where it is not legally restricted, waterproofing is a highly technical trade where DIY mistakes are costly and sometimes invisible until serious damage has occurred. Always engage a qualified, experienced waterproofing contractor. You can find local professionals on tradedirectory.co.nz.

If the waterproofing involves plumbing penetrations or drainage connections, those elements must be completed by a licensed plumber registered with the Plumbers, Gasfitters and Drainlayers Board.

Sources & Further Reading

• MBIE Building Performance — NZ Building Code
• BRANZ — Moisture and Weathertightness Guidance
• Licensed Building Practitioners — Find an LBP
• Ardex NZ — Waterproofing Systems
• Sika NZ — Waterproofing Products
• Consumer NZ — Your Rights with Tradespeople