The Australian Standard 3740-2004 is the relevant Standard that applies to waterproofing.
Modern construction of buildings provides a desirable finish for a hobless shower as it is easy to access. This forms part of most modern houses, however if the waterproof membrane and methodology of installation have not been installed in the correct manner, then leaking showers can occur. The evidence of leaking showers can be from various sources.
A leaking shower may affect the areas below the building. Where there is a ceiling below, then the leaking shower can be quite obvious.
Where the leaking shower is noted to the ground floor area the problem can be less obvious.
Leaking showers can also be shown up at the door opening and can affect the floor coverings abutting the door to that room.
In many cases the door jambs and architraves can be significantly affected by swelling and discolouration due to substantial dampness.
Many bathrooms now are provided with toughened frameless glass which is far more difficult to waterproof. This is classified as an unenclosed shower area.
Where an unenclosed shower area is provided, then the defect only exists if dampness is evident to the door jamb and architraves, as noted above or external of the room, including areas below.
What may not be so evident is the extent of water damage that can occur to the areas below showers to the first floor level. The extent of damage requires further investigation and exploratory works. There is concern where particleboard sheet flooring, or similar, has been installed below the wet areas, or bathroom. This particleboard sheet flooring can be affected by significant deterioration and in extreme cases the whole of the sheet flooring, including the shower area, can physically collapse.
In undertaking investigations for a leaking shower it is important that full investigations be completed so that the extent of damage in concealed areas is determined and adequate remedial works are undertaken. It is also possible there may be some degree of rot and deterioration to enclosed wall framework, mainly behind the shower area.