Waterproofing a tiled balcony



When not properly waterproofed a tiled balcony can lead to a multitude of problems, especially a balcony sited above other rooms in a property. Water run-off from balconies can cause extensive water damage to interiors and result in damp, peeling paint and other structural problems that can be expensive to fix.

Where leaks or water damage has already started to occur, either due to lack of waterproofing or as a result of waterproofing failure, there are two courses of action to consider.


Before resorting to the second, more expensive option, you might want to try and resolve waterproofing issues by applying products onto the existing tiled area. Bear in mind, however, that this step assumes that the substrate or concrete base is in sound condition. Where obvious damage is visible to the substrate, such as cracks or erosion, applying products over the surface to resolve leaks will result in failure, since damage to substrate or concrete slabs must be repaired prior to waterproofing.


The second option is to remove the tiles in order to apply or re-apply waterproofing. A project of this nature is best left to a professional contractor and it is in your interests to obtain three quotations from local contractors and ask for references on previous jobs undertaken.

Since every balcony is different in design, this article takes a general look at the topic of waterproofing a tiled balcony using a variety of products that are applied onto the existing tiled surface.

All waterproofing jobs, no matter what the design of a balcony, need to fully address water drainage points, as well as wall and floor joints. Inspect the balcony for signs of failure. Common signs to look out for are:


  • Insufficient drainage
  • Cracked or missing grout
  • Cracks or damage to substrate
  • Failed or missing waterproofing membrane
  • Signs of efflorescence

Efflorescence is caused by an accumulation of salts that builds up on top or around the edges of balconies. Since efflorescence cannot form without water, visible efflorescence is a sign that water is pooling or not draining properly.



Waterproofing membrane

A waterproofing membrane can be installed around the perimeter of a tiled area to effectively provide a waterproof barrier. Follow the recommended application instructions to ensure successful installation.


Penetrating water repellent

Applied as a sealer over grout, a penetrating sealer blocks water penetration. When replacing cracked or missing grout apply a penetrating water repellent product to ensure adequate waterproofing. Any external tiling should be treated with penetrating water repellent and re-application applied as part of a regular maintenance programme.



Where grout has started to degrade, either by crumbling or cracking, complete removal and re-application is necessary.


Damp or waterproofing treatment

Where paint has started to bubble or peel due to damp, you will find damp or waterproofing treatments that can be applied. Follow the manufacturer’s recommended guidelines for application.

Correct drainage

An exterior balcony that is open to the elements should allow for adequate water run-off or drainage to ensure that pooling or water build up does not occur.

Where possible, drainage should be integrated into the existing downpipes of the property to reduce the risk of water damage, or a downpipe fitted to allow water removal. Too many properties are incorrectly fitted with a pipe or open drain that allows water flow from the balcony only for that water to run down exterior walls. This method of drainage can cause extensive damage to property walls.


You will find a variety of waterproofing options at your local Builders Warehouse or hardware store, each designed for a specific purpose. If in any doubt as to the correct product to use for your application, ask for advice from the manufacturer/supplier or sales staff.


Janice Anderssen


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