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Waterproof Membranes for Concrete Slabs: A Guide to Selection Criteria, Standards and Products

When selecting a waterproof membrane for suspended concrete slabs below paved or landscaped areas in Perth, it is crucial to consider the following performance criteria as per the relevant Australian standards and codes:

  1. Water resistance: The membrane must comply with AS 4654.1 for external above-ground use and resist water penetration, especially in areas prone to flooding or high moisture levels.

  2. Durability: The membrane should be able to resist the weight of the concrete slab, foot traffic, machinery, and other sources of potential damage while being resistant to environmental factors like UV exposure and chemicals. The NCC sets standards for the design and construction of buildings in Australia, and Section E2.2 outlines the requirements for structural durability.

  3. Flexibility: The membrane should be able to withstand movements and expansions in the concrete slab without cracking or tearing. AS 4654.1 specifies that the membrane should have an elongation of at least 150% and a recovery of at least 90%.

  4. Adhesion: The membrane must adhere strongly to the concrete substrate and prevent water from seeping through any gaps or weak spots. AS 4654.1 also sets standards for adhesion, stating that the membrane should not delaminate or detach from the substrate after installation.

  5. Compatibility: The membrane should be compatible with the concrete mix, drainage system, and other construction materials used in the project. The NCC provides guidelines for the compatibility of building materials in Section E1.

  6. Compliance: The membrane should comply with AS 4654 for waterproofing membranes and the NCC.

Here are some examples of waterproof membranes that meet these performance criteria:

  1. Sheet Membranes: Sheet membranes are widely used for sub-surface waterproofing of suspended concrete slabs due to their excellent water resistance and durability. Some popular sheet membrane options include:

    1. Ardex WPM 1000 - This membrane complies with AS 4654 and the NCC, has excellent elongation and recovery properties, and is highly resistant to water, chemicals, and UV exposure.

    2. Wolfin Waterproofing Membrane - This synthetic membrane is highly durable and resistant to mechanical damage, root penetration, and environmental factors. It is also compliant with AS 4654 and the NCC.

    3. Cosmofin Waterproofing Membrane - This single-ply membrane has high flexibility and excellent adhesion properties. It is highly resistant to puncture, chemicals, and UV exposure and complies with AS 4858 and the NCC.

  2. Liquid Applied Membranes: Liquid applied membranes are also a popular choice for sub-surface waterproofing due to their high flexibility and seamless application. Some popular liquid applied membrane options include:

    1. Sikalastic 560 - This two-component, highly elastic membrane complies with AS 4654 and the NCC, can be applied in a single coat, and is highly resistant to water, chemicals, and abrasion.

    2. Crommelin Aquablock Plus - This single-component, water-based membrane is highly flexible, easy to apply, and compliant with AS 4654 and the NCC.

    3. Mapei Mapelastic Smart - This two-component, highly elastic membrane has excellent flexibility, is highly resistant to movements and vibrations, and complies with AS 4858 and the NCC.

By considering these performance criteria and choosing the right waterproofing membrane for your project, you can ensure that your suspended concrete slabs below paved or landscaped areas remain protected from water damage and last for years to come.


  • Australian Standard AS 4654.1: Waterproofing membranes for external above-ground use - Part 1: Materials

  • National Construction Code (NCC) - Volume Two: Building Code of Australia (BCA), Section E1 and E2.2.

  • Ardex WPM 300:

  • Ardex WPM 1000:

  • Wolfin Waterproofing Membrane:

  • Cosmofin Waterproofing Membrane:

  • Sikalastic 560:

  • Crommelin Aquablock Plus:

  • Mapei Mapelastic Smart:

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