The Problem, The Solution
From a potential problem..
Leaks due to Ledge/Wall Joint Expansion
Floor joist drying shrinkage most often occurs in new buildings causing the wall/ledge joint to expand as the bath or shower tray ledge drops down with the level of the floor.
Deflection in baths and shower trays can occur under the imposed load of water and occupant. Acrylic baths on metal legs often deflect causing the wall/ledge joint to expand.
Floor joist weight settlement can occur under the imposed load of an occupied bath causing wall/ledge joint expansion.
Wall Substrate Deterioration due to Moisture Penetration
Timber stud partition drying shrinkage and normal structural adjustment in new buildings can create hairline cracks at wall junctions and passages for moisture ingress.
Cement based tile grouts are water resistant - not waterproof, and tiled partitions are not totally rigid. In such hi-use hi-performance shower environments with limited drying times, moisture contact with wall substrates is an eventual probability.
Water sensitive backgrounds such as plasterboard and plywood absorb moisture and loose material integrity. This causes a reduced or loss of adhesion between the tiles and wall followed by an accelerated general installation failure.