PS1 - Design Author

Waterproofing Design

Key Points

🔹 Design:

  • Waterproofing must be treated as a specialist design discipline.

  • Requires assessment of structural detailing, risk, site conditions, and long-term performance.

  • Correct product selection and a skilled applicators are essential.

  • Even Type B designs need expert input—concrete alone isn’t waterproof.

🔹 Standards:

  • All below-ground waterproofing is an Alternative Solution in NZ.

  • No Acceptable Solution exists in the NZBC—compliance must be proven through project-specific design and documentation.

🔹 PS1 – Producer Statement (Design):

  • Confirms the design meets NZ Building Code requirements if followed as specified.

  • Must be issued by a suitably qualified professional.

🔹Designing above the legislation line:

An Alternative Solution is a proposed method or system that demonstrates compliance with the Building Code but is not contained in the Acceptable Solutions or Verification Methods.

🔹This requires:

  • Evidence of performance (test data, technical literature, BRANZ /Codemark Appraisal, etc.)

  • Experince/industry specialists/Guidance Documents

  • Often a PS1 design by a suitably qualified professional

  • Council review and approval

Compliance with the NZ Building Code & BS8102:2022

The Building Act 2004 sets out the framework for construction, requiring all building consent applications to demonstrate compliance with the New Zealand Building Code. As part of our design service, we provide:
✔ Product and system specifications
✔ Comprehensive documentation proving compliance
✔ Ongoing site inspections and quality assurance

Waterproofing in New Zealand is a specialised task, It is therefore extremely important that the correct design is considered and provided for below ground waterproofing.

With the absence of a dedicated code or standard supporting below ground waterproofing design in New Zealand, it makes a reliance on overseas standards a necessity.

BS 8102:2022 – Code of Practice for Protection of Below Ground Structures Against Water Ingress, highlights the importance of early-stage waterproofing design integration in construction projects, it provides recommendations and guidance on methods of dealing with and preventing the entry of water from external sources into structures that are partly or wholly below ground.

The Importance of Specialist Waterproofing Design

Successful waterproofing demands specialist expertise. Common causes of failure include:

- Poor workmanship
- Incorrect product selection
- Compromised specifications due to budget constraints
- Misuse of accredited products that are unsuitable for the project

Ensuring Long-Term Success in Waterproofing

With basement spaces becoming increasingly valuable, it is crucial to implement the right combination of materials, expertise, and planning from the outset. Our mission is to provide manufacturers, specifiers, and end clients with complete confidence in their waterproofing solutions—ensuring projects are completed correctly the first time, every time.