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Understanding the Performance of the Building Regulations – Waterproofing

The measure of performance of a waterproofing system is associated with assessing the key functions of waterproofing itself.  By definition, a “Waterproofing System” is a combination of elements that are required to achieve a waterproof barrier.  The term “Waterproof” is defined as the property of a material that does not allow moisture to penetrate through it.

Given that the existing provisions require the area outside of a shower to be complete with a Type 5 Perimeter flashing, the room itself, in conjunction with the completion of waterproofing in a shower and bath etc, provides a Wet Area with a barrier that does not allow water or moisture to penetrate into adjacent rooms and building elements.  This level of performance is key in the success of preventative damage due to moisture movement in Wet Areas.

Moisture escaping a shower enclosure is the number one cause of moisture related issues in Wet Areas within the building industry.  The volume of water used when showering, the frequency with which a shower enclosure is used and the inability for shower enclosure screeded beds to subsequently “dry out”, all contributes to moisture escaping the enclosure itself.

The most common causes of moisture escaping shower enclosures is not due to the failure of waterproofing, but rather issues relating to shower screen positioning, shower screen maintenance, failure of sealants and tiling related issues.

More specifically, common causes include:

  • Shower screen not adequately sealed after installation.
  • Shower screen sealing worn away due to regular cleaning, and sealant not maintained.
  • Shower screen incorrectly positioned on the shower hob.
  • Water escaping between top of waterproofing membrane and bottom of tile on top of hob.
  • Water escaping below a shower screen frame, and over the top of water stop angles due to the minimum 5mm protrusion not being compliant (AS3740-2010 Figure 3.6).
  • Water easily escaping from the frameless shower doorway opening, due to lack of water deflection devices directing water back in towards the centre of the shower (Water stop flush with top of tiles at shower door opening location).
  • Water migration behind wall tiles and over the shower water stop.

It is not uncommon for moisture to escape a shower enclosure, particularly given that there are multiple trades involved in the construction phase that all work together to ensure that the shower enclosure itself is built as waterproof as can possibly be achieved.  Unfortunately, however due factors outside of the control of building regulations, the escape of moisture and water from a shower enclosure is a common occurrence.


For any other advice of a technical nature, Wet-seal’s highly experienced technical expert, Robert Rath, will be happy to take your call.  Robert can be contacted on 0413 008 303 or via email rrath@wet-seal.ws

Alternatively, please speak with your local Franchisee directly.  Details of how to contact your local Franchisee can be found at Find A Franchisee