How to fix leaking balconies

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, we 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 following:

  • 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

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.

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.

Repairing a Leaking Balcony

Waterproof membrane best for remedial & repairs works.

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.


  • 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.