REMOVE WATER
The basic principle of waterproofing is to “remove the water off a surface as quickly as possible”. If a surface is sufficiently and correctly sloped, this will alleviate any issues around ponding and standing water.
Water also moves by “coercion” – once the water moves in a direction, it pulls the surrounding water along with it.
DRAINAGE
A 75mm drainage hole for every 44 sqm of “catchment” area is recommended.
The catchment area is the whole horizontal surface of a balcony, 50% of the vertical surfaces that drain onto a balcony and any additional roof area that drains onto this surface.
PONDING
If the slope and drainage of a balcony is incorrect and “ponding” takes place, the water will find a way through into the screed and slab, and eventually into the underlying area.
The above problems are further enhanced by the poor quality of the screed, the tile adhesive and the grouting.
This is a common problem and requires a structural remedy to permanently solve the moisture ingress issues.
WATER REPELLENT
A water-repellent treatment on the grouting, or whole surface, can be done to further enhance the water repellency of the surface.
Attention must be given to the area leading into the drains, to ensure a fully sealed lip and channel into the drainpipe itself.
This same principle applies to flat roofs and decks.
WeatherPrufe Paints have worked with several contractors who understand these principles and have successfully completed the refurbishment of problem roofs and balconies.
Don McWilliam
Director | WeatherPrufe Paints