Tiled waterproof deck – water leaks

If there is a habitable space below the waterproof deck, any leaks through the deck should be attended to without delay.

Causes

There is no waterproof membrane behind the tiles

The waterproof membrane was damaged during tiling 

The membrane was poorly applied

Tiles were applied before the liquid applied membrane had cured

Water is ponding on the surface and seeping thorough membrane joints

Grouted or sealant filed joints have failed

The membrane was not designed to have tiles glued to it 

Listed under: Exterior, finishes, tiles, membranes, balconies, decks, framing, moisture, leaks, weathertightness

Cause

There is no waterproof membrane behind the tiles

Repair

  • a membrane is a crucial component of a waterproof deck
  • if there is no membrane, the tiles will need to be removed, any damage to the building assessed and repaired and then a waterproof membrane installed before tiles are reinstalled
  • it is crucial that any damage from the leak, including wet timber, mould or rot in framing timber, is fully addressed before a new membrane is installed. Assessing damage from leaks is skilled work that not any tradesperson can do. Looked for a practitioner such as a registered building surveyor with experience in this area
  • repair work to the substrate and framing under a waterproof deck and membrane application is all restricted building work under the Building Act. Anyone engaged to carry out this work must be a licensed building practitioner or be supervised by an LBP
  • installation of membranes is not a DIY job. Membrane manufacturers and suppliers typically train and license applicators in the use of their products. A warranty may only apply where application or repair is carried out by someone licensed by the supplier

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Cause

The waterproof membrane was damaged during tiling 

Repair

  • see the first repair above for general guidance
  • the membrane will need either repair or replacement

  • if the tiles were installed by a tradesperson or company in recent years, call them back to find a solution. In this situation, they are generally liable for the damage they have caused

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Cause

The membrane was poorly applied

Repair

  • see the first repair above for general guidance
  • if the membrane was installed in recent years, call the installer back. Membranes still under warranty should be repaired or replaced by the contractor who carried out the original membrane application or by another applicator approved by the membrane supplier

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Cause

Tiles were applied before the liquid applied membrane had cured

Repair

  • see the first repair above for general guidance
  • it is likely that the membrane will need to be replaced
  • if the tiles were installed by a tradesperson or company in recent years, call them back to find a solution. In this situation, they are generally liable for the damage

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Cause

Water is ponding on the surface and seeping thorough membrane joints

Repair

  • see the first repair above for general guidance
  • ponding suggests that either drains are blocked or drainage is inadequate, or the substrate and framing under the membrane have not been properly designed and constructed to allow effective draining to take place. Determine the underlying cause of the problem and then make repairs based on addressing that
  • if membrane joints are leaking it is likely that the membrane will need to be replaced

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Cause

Grouted or sealant filed joints have failed

Repair

  • see the first repair above for general guidance
  • it is likely that the membrane will need to be replaced
  • if the membrane was installed in recent years, call the installer back. Membranes still under warranty should be repaired by the contractor who carried out the original membrane application or by another applicator approved by the membrane supplier

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Cause

The membrane was not designed to have tiles glued to it 

Repair

  • see the first repair above for general guidance
  • the membrane will need to be patched or replaced
  • not all membranes can have tiles directly applied to them. Direct fixing in this way is also outside the scope of Building Code Acceptable Solution E2/AS1

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