​How to Fix Leaking Balconies

Enduring Solutions for Balcony Leaks: The Right Products, Systems and Expertise for Durable Waterproofing

Repairs to leaking balconies require expert & correct waterproofing products & method to permanently stop water leaks.

Providing a membrane system that "works & lasts" is not difficult, however our Team has come across so many balconies that should not leak in the first place and then the repairs also fail to provide a solution to the problem.

As Registered Building Practitioners AND Certified Waterproofers, the Findlay-Evans Team always check leaking balconies with respect to balcony design & structure as well as the waterproofing system.

Very often leaking balconies are a combination of the above:

  • Failed waterproof product & system 
  • Lack of, or insufficient number of, expansion joints
  • Inadequate and/or no drainage
  • Minimal or no falls built into the balcony design

A waterproofing company that thinks CONSTRUCTION

A recent insurance survey has shown that “Balcony Waterproofing” has the highest failure rate of all areas in the building envelope.

However only 1.8% of the total construction cost is spent on waterproofing membranes for balcony areas,  and yet leaking balconies account for a staggering 83% of building defect complaints.

Balcony Waterproofing Systems

  • Balcony areas are exposed to full climatic conditions and if installed incorrectly or inferior products are used, the chance of failure is high.
  • Repairs & modifications to a balcony membrane & surface provides an essential and integral part of the building envelope and should not be taken light-heartedly.
  • Waterproofing balcony surfaces, especially balconies with rooms below and rooftop terraces should be a well thought out process and not reliant on cost alone.
  • Ideally membranes are installed correctly from the outset and with quality products - as failure of balcony waterproofing can result in catastrophic water damage to structures below and even complete collapse.

View Video Below

Experts suspect poor waterproofing in Berkeley balcony collapse. Sudden collapse of a Berkeley balcony last week that killed six and injured seven, experts say it's obvious what happened: water got into the balcony and didn't get out, rotting the wood that kept it in place. Read about this tragedy here.


The results  of poor workmanship was sadly demonstrated in 2014 in the USA when  an apartment balcony collapse with loss of lives and major injuries. The Berkeley balcony that failed was only 8 years old.

Construction crews remove pieces of a balcony that collapsed in Berkeley, exposing what appears to be dry rot lumber. The collapse killed six people and injured seven a few blocks from UC Berkeley. (Mark Boster, Los Angeles Times)

Tiling on its own is not an effective or acceptable as a waterproof barrier.


Despite the severity of the potential consequences of balcony failure, many property owners do not use qualified & certified waterproofers; often allowing tilers to apply the waterproofing membrane & also use sub standard products.

Commercial Balcony Repairs - Qualified Builders

As both Registered Building Practitioner & Certified Waterproofers, our Team offers construction & structural knowledge combined with waterproofing expertise.

Waterproofing Details for Balconies

  • Balcony membranes require a membrane system that provides a permanent water barrier to all wall upturns, floor, around drains, balustrade & all points of penetration etc.
  • Water has to be prevented from penetrating beneath the balcony surface, where structural damage will compound over time and is often invisible.
  • Water can track great distances from the point of entry.
  • A basic principle in construction is to factor in building movement - the normal cyclic expansion & contraction of materials.
  • The waterproof membrane has to flex and move with not only the balcony structure but also the associated adjacent building envelope.

To assist the public & building practitioners, the VBA has developed a list of important points to remember when designing, assessing, approving  waterproofing standards for balconies.

Victorian Building Authority Guide - Here

Repairing a Leaking Balcony

Waterproof membrane best for remedial & repairs works

Extreme Flexibility: Flexible Waterproofing Membrane

Liquid Applied Membranes

Seamless liquid applied elastomeric membranes have become the ultimate solution for balcony, deck and above ground waterproofing.

These extremely flexible membranes are capable of resisting UV rays - important if under timber decking - and also coping with structural movement and deformation.

Liquid Applied Membranes are a cost effective solution to waterproof a new balcony and/or repairs to existing balconies.

Case Study- Video Below

Liquid Applied Membranes

  • Cost effective, robust & long life waterproofing.
  • Capable of bridging cracks and joints.
  • Fast installation with minimal disruption to building occupants.

Liquid Applied Waterproofing Systems are the ideal membrane to use as a sealant around the most complex of balcony details - for example around handrail supports, joins & seams, roof penetrations, rainwater outlets.

Waterproofing Membrane under Timber Decks

Seamless liquid applied membranes have become the ultimate solution for deck waterproofing. A quality balcony waterproofing  membrane is especially essential for preserving any area underneath  timber decking  from water causing ingression damage to rooms below.

Balcony Waterproofing - Australian Standards

Summary of the Article key points:

  • Residential multi-story, multi-dwelling, apartment buildings are experiencing an alarming frequency of building defects, most commonly caused through waterproofing failure.
  • Developers were identified as partly responsible for the condition of the building, with a call to be financially responsible.
  • Balconies were identified as a major cause of waterproofing problems, with the assumption that “proper waterproofing membranes have not been installed”.
  • Faulty windows and installation process causes considerable water leaks into walls and ceilings. Pressure issues identified as causes were nominated as; a failure to pick up defects through the building surveyors inspection process; plus the cost pressures to use cheap (inferior) materials to save money.
  • The market has inconsistencies in 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.
  • The Victorian Government is making new laws to protect consumers whilst also recognising the ‘overwhelming majority of builders’ do the right thing.
  • We recommend liquid applied membrane systems for the Australian climate as the most practical and economic products for a secure job.
  • A basic principle with new construction buildings is to view the job with the perspective that building movement will occur and therefore to secure all wall/floor joints, drains, balustrade, water exit points, hobs, sheet joints and movement joints.

Balcony Waterproofing Without Removing Tiles

Opinion piece by Paul Evans - President, Australian Institute of Waterproofing (AIW) 2017-2020


  • Re-Grouting and sealing is definitely not the way to repair a leaking balcony that has an existing  defective membrane.
  • Sealing the existing tiles would probably stop or slow down leaks for a while until it moves and cracks the grout again then it would start to leak.
  • Laying a new waterproof membrane over a clean existing surface can work if the existing tiles are soundly fixed.
  • There may be some blistering with the new membrane due to water vapour trapped within but that is easily dealt with - balcony repairs just take longer while you wait for the vapour to dissipate ( with the new membrane over the top).
  • When repairing balconies it is alway better to have the A/C units etc  removed while restoration works  are done  - a much tidier job.

Membrane Protection for Balconies

Instant turf is a popular finish for many balconies & rooftop terraces. However Instant Turf is NOT a waterproof membrane itself - we have a high performance waterproofing system which also includes  a premium protection between the membrane & instant turf.

Our Team provide a tough, robust and durable external laminate protection sheet using our premium system:  ARMA-BLUE

  • This composite product uses cross linked foam and has many benefits over conventional CoreFlute Board.
  • This is a self adhesive or "sticky back" impact resistant foam sheet that is laid down and then the instant grass is installed over the ARMA-BLUE.
  • Arma Blue protection sheet assists with allowing water run off.
  • Many balcony designs have limited fall  and unless the waterproof membrane can "hold" water they will break down over time.
  • Liquid Rubber Membrane  which is designed to "ponding water",  unlike a great deal of other membranes.
Balcony Instant Grass System


Waterproofing Contractor - Testimonials

Liquid Rubber

Melbourne Environmentally Friendly Coatings

Multi Level Apartment Balcony Waterproofing

Paul Evans is very professional in this approach towards giving the right advice regarding different products he uses and the best product to use for the given task. I would highly recommend Paul and Liquid Rubber to anyone seeking quality work performed by a professional team. 

Virgon Construction Hawthorn Vix - Renato Virgona Manager/Director, Virgon Constructions

waterproofers-Melbourne