Builders and tilers beware. Efflorescence was formerly an occurrence that was considered a 'maintenance issue' for building owners. Since 2007 however, it is considered a liable defect which is referred to in the national publication: 'Guide to Standards and Tolerances'.
At the bottom of page 49 of the guide, is the following clause:
"13.08 Calcification and efflorescence associated with decks and balconies
Calcification or efflorescence caused by water coming from a deck or balcony that occurs on walls below or beside the deck or balcony; or that appears in the mortar joints of the deck or balcony tiling, is a defect. Activities of others, such as owners watering plants, may also contribute to the efflorescence, which may not be attributed to the work of the builder."
This guide does leave some room for dispute and interpretation if for example the problem is attributed to "watering plants". Proving that kind of argument can be very cloudy and prove very expensive, especially in court.
The best solution is to design the problem out completely with Efflock. The owner can water plants with out a care - belts and braces protection!