A common issue with leaking balconies; a lack or failure of the waterproof membrane, and poor execution. Note no upturn to the walls to protect this critical area.
Remedy: The only way to provide a long-term solution that satisfies the contractor's obligations under the Home Building Contract Act 1991 (HBCA), is to replace the waterproof membrane. Unfortunately this necessitates the replacement of all tiles.
Other methods such as clear sealing and grout replacement does not provide a long term solution and contravenes the HBCA.