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What are the Australian Standards for waterproofing bathrooms?

April 12, 2022

Australian Standards for waterproofing bathrooms

In Australia, waterproofing guidelines are set by the Building Code of Australia and Australian Standards (AS-3740 1994). This ensures that waterproofing is carefully regulated for safety and to prevent the deterioration of buildings due to insufficient waterproofing.

The standards require:

  • Shower areas must be entirely waterproofed
  • Bathroom floors above ground level, or timber, plywood or particleboards must be entirely waterproofed
  • Shower walls must be waterproofed to 1800mm at least
  • Walls must be waterproofed to 150mm at least
  • Step down areas must b e waterproofed to 150mm at least

Usually, waterproofing is installed during the construction phase using a membrane within the bathroom. It is then protected using liquid sealants on tiles and the floor. Finally, a silicone sealant is used to close gaps where the floor and walls are joined.

Who can install waterproofing in Australia? 

In Queensland, work must be carried out by a Queensland Building and Construction Commission licensee who can issue a Form 43 for the work completed. Waterproofing is part 16 of this form. Fraser Coast Waterproofing can issue the required Form 43/16.

Signs your renovated bathroom hasn’t been waterproofed correctly

There are several signs that your bathroom hasn’t been waterproofed correctly. Although many of these are visual signs, they must be remedied quickly to prevent structural damage. A quick response provides the best results.

Visual problems that you may observe include:

  • Paint blistering, bubbling, or peeling – painted surfaces may have bubbles, the paint may have lifted away from walls forming blisters with plaster crumbling underneath 


  • Rising damp, any signs of internal damp – this appears as a tide mark on the wall, rising from the floor and may have white stains on the wall or dark patches that are damp to the touch


  • Mould and mildew – not your usual surface mould that sometimes appears in bathrooms, this type of mould will not be removed easily and reappears quickly once cleaned away


  • Rust stains on any concrete areas – usually light orange in colour, may appear as a bleeding orange mark


  • White drip stains that can be seen on the edge of balconies and stairs located adjacent to wet areas


  • Cracked walls – visual cracking that is only apparent in wet areas of the bathroom


  • Damage to tiles, grout may be damaged, and tiles are unstable – usually because of the rising damp and other problems, water has seeped into tiles, and these become detached from the wall or appear to be loose.

 If you have noticed any of these issues and live on the Fraser Coast, it is best to contact Fraser Coast Waterproofing today on 0423 964 496 or contact us online.


It's important that we investigate whether your waterproofing has failed and what remediation needs to be done to repair the damage as it can quickly lead to other problems.


We have 15+ years experience and are widely regarded as the the best waterproofers in Hervey Bay .

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