Leaking Balcony Repairs

June 01, 2017

"Efflorescence" occurs only in the presence of water.


Complete Strip Out - Leaking Balcony

If It Has a Balcony, It Will Leak

This unfortunate statement “If it has a balcony, it will leak” was taken from an article titled "Melbourne’s high-rise nightmares taking a tall toll on residents and investors" from The Age, Melbourne 25th September 2016.
Though this article was referring to Melbourne’s booming construction in the apartment sector, many cities across Australia are experiencing similar issues.
There are several key points within this article I would like to emphasise

  • Residential multi-story, multi-dwelling, apartment buildings are experiencing an alarming frequency of building defects, most commonly caused through waterproofing failure.
  • Balconies were identified as a major cause of waterproofing problems.
  • This has led to the common assumption that for many multi-level balconies “proper waterproofing membranes are not installed”.
  • The market has inconsistencies about Insurance cover, both from building trade cover and the residential owners cover. Resulting in the building owner necessitating to self-fund the corrections to the building.

This article diving into the question “Why is my balcony leaking” has been supplied by Paul Evans, Findlay & Evans Waterproofing – President of Australian Institute of Waterproofing (AIW).

Construction methods are always changing and adapting.

I have noticed recently, either for reasons of design and/or cost considerations, changes in balcony construction methods which have a direct impact on the success or otherwise of the waterproofing membrane.
Melbourne balcony waterproof

Multi Level Apartment Balconies

  • Many balconies are currently being constructed with minimal falls to the substrate; particularly evidenced in multi-level apartments.
  • This design has a significant effect on the choice of waterproofing product, installation method and tile adhesives used.
  • The balcony membrane must be capable of “standing water”; as a balcony with minimal fall will have water ingress through the grout resulting in moisture “ponding” between the membrane and tiles.
  • If the waterproofing membrane selected cannot withstand ponding water – and many waterproofing products on the market cannot – over time and together with the normal cyclic thermal contraction and expansion of a building, this will cause the membrane material to break down and/or joint failure and cause water leaks.

Why do Balconies Leak ?

  • Balconies and walkways are exposed to the destructive forces of the elements: rain, wind, sunlight, and freezing conditions.
  • All too often, penetration of water is through the top balcony surface and exposed edges of both reinforced concrete  and timber framed balconies.
  • This leads to deterioration of the balcony structure and significant defects occur, such as concrete spalling.
  • Accumulation of calcium crystals and salts is known as “Efflorescence”.
    Efflorescence only occurs on balcony surfaces due to the presence of water.

Why is My Balcony Leaking?


Balcony damage due to water leaks

Damage due to water leaks

In my experience, there are recurring issues causing waterproofing failure:
  • Inadequately waterproof detailing from balcony to wall interfaces.
  • Railing post and penetrations causing water ingress due to poor preparation and detailing.
  • Poorly detailed balcony surface transitions, interfaces and penetrations can lead to water ingress into occupied spaces below which in turn may lead to serious structural damage.


Unfortunately, many of these issues are not always taken into consideration when contractors/specifiers/designers are deciding on waterproofing products and methodology for constructing balconies.
This may result in the owners, investors and owners’ corporation having to face the challenges of solving future leaking balconies.

Best Balcony Waterproofing Product

  • Should have comparable expansion capabilities as the balcony structure it self.
  • Strongly adheres all horizontal & vertical surfaces i.e balcony surface & adjoining walls/structures.
  • Create a permanent water tight bond & seal around all balcony edges, penetrations, balustrades and interfaces.

Can balconies be repaired without removing tiles ?

To give a personal  opinion about remedial waterproofing system for leaking balconies!

  • Re-grouting and surface sealing is not the way to repair a leaking balcony if it has been established there is a defective membrane.
  • This band-aid method may stop or slow down water leaks for a while. 
  • That is until the balcony moves and cracks the grout again and inevitably the balcony will start to leak all over again.
  • Unfortunately in most cases of leaking balconies to provide a long term solution is a complete strip off, re-install a new membrane, screed & tile or whatever other finished surface  i.e instant turf.

After numerous attempts at stopping water leaks, this balcony had to be stripped and membrane re-installed.

Balcony & walkway stripped back & new membrane.

Successful Balcony Restoration & Repairs

Rooftop, Balcony Waterproofing Membrane

Rooftop Balcony & Instant Turf

Educational Facility with Instant Turf

  • Using Correct Waterproof Product – selecting long life membranes that are also cost-effective and suitable for the balcony design and conditions.
  • Membrane must be capable of bridging cracks and joints within the sbalcony substrate.
  • Correct Waterproof System -  make water tight all balcony surfaces, interfaces, and penetrations.
  • Membrane Flexibility - the waterproof membrane must be able to move with the normal contraction & expansion of the balcony envelope.
  • Waterproof Membrane must be able to withstand “ponding” water.
  • Waterproof System installed with minimal disruption to building occupants.

Read Our Article  - First Published March 7, 2017


Waterproofing Company - Melbourne

View Video Below
Read about Findlay & Evans Waterproofing who are

Registered Builders for structural repairs: Building Services Australia