CodeMark waterproofing membrane or appraisal: what the difference means
Certificates, appraisals and warranties are three different things. Here is how they fit together
When you’re comparing quotes for a deck or flat roof, you’ll often see a membrane described as “CodeMark certified”, “appraised” or “warranted”. They sound similar, but they do different jobs. Knowing whether you’re getting a CodeMark waterproofing membrane, an appraised one, or neither helps you ask better questions and understand how the product fits into your building consent.
What CodeMark is
MBIE describes CodeMark as the only deemed-to-comply product certification scheme in New Zealand. It’s voluntary, and MBIE administers it. A product with a current CodeMark certificate, used within the scope and limitations on that certificate, has to be accepted by a building consent authority as complying with the Building Code clauses it covers.
MBIE’s page comparing CodeMark certification and product appraisals says CodeMark has legal status equivalent to an Acceptable Solution or Verification Method. If a certified product is used within its scope and limitations, the council can’t ask for further evidence that it complies.
What a product appraisal is
An appraisal is a technical opinion from an organisation that has assessed a product. MBIE says appraisals have no legal standing, but they can form a useful part of the evidence of compliance. Whether the council accepts that evidence comes down to its professional judgement on your project.
- Deemed to comply: CodeMark yes, appraisal no.
- Technical information about the product: both provide it.
- Certification body accredited and scheme run by MBIE: CodeMark yes, appraisal no.
- Can support a consent application: both can.
A recent determination shows how this plays out
In Determination 2026/039, issued on 15 October 2026, MBIE considered a Wellington council’s handling of a consent that relied on an appraisal for a bamboo cladding product. MBIE repeated that councils must accept deemed-to-comply solutions, including current CodeMark certificates, and that an appraisal is a technical opinion on fitness for purpose with no specific legal standing under the Building Act.
MBIE also said a council shouldn’t refuse an appraisal just because of who the appraiser is. It has to weigh the evidence. In that case MBIE found the council hadn’t given enough reasons for its purported refusal. For homeowners, the takeaway is simple: an appraisal is evidence the council weighs, while a CodeMark certificate used within its scope is accepted.
Questions to ask about any CodeMark waterproofing membrane
- Is the certificate current? MBIE keeps a Product Certificate register where you can check it.
- Does the scope match your job? The register shows limitations of use and maintenance requirements. A membrane certified for one type of deck or roof may not cover yours.
- Is it being installed the way the certificate says? Substrate, falls, laps and details all matter. We cover the basics in our substrate preparation guide.
- If it’s appraised instead, what else supports it? The design, the details and the installer’s records all form part of the evidence.
Warranties are a separate thing again
A warranty is a promise from the manufacturer or installer. It isn’t a certificate and it isn’t the Building Code’s durability requirement. For example, on our HydrEpoxy jobs (ARDEX WPM 300, a negative-side system for basements and below-ground walls), ARDEX gives a 10-year product warranty and Auckland Waterproofing Experts gives a separate 5-year workmanship warranty. Neither one changes what the Code requires, which we explain in our post on B2 durability waterproofing.
You can also read about the membranes we use and what a PS3 for waterproofing is for.
Not sure what your quote is offering?
If you’ve got quotes with different membranes and aren’t sure how they compare, we can talk you through them. Call us at Auckland Waterproofing Experts on 022 630 6434 for a free site visit. We’ll explain what we find in plain English and send you an itemised quote. You can also read our waterproofing FAQs.
Email aucklandwaterproofing@gmail.com. We’re available 7am to 7pm, Monday to Saturday, based in Castor Bay and working across Auckland and the North Shore.
