Why balconies fail
- No membrane at all. Very common — tiles laid straight onto a screed, with the tile joints treated as the waterproofing.
- Falls running the wrong way. Toward the building instead of away from it, so water sits against the threshold.
- No drip edge. Water wraps back under the slab edge and tracks into the wall below.
- Rigid coating on a moving slab. The membrane cracks at exactly the points that move most.
- Blocked or absent outlet. A balcony with no scupper becomes a shallow pond in a Cape winter.
- Failed junction at the door threshold. The single most common entry point on any balcony.
The system we use
A polyurethane membrane, reinforced at the movement joints and dressed up all abutments and into the outlet, over a screed corrected to fall away from the building. Then either a tile on a drainage mat, or a trafficable top-coat where the finish level cannot be raised.
PU is specified over acrylic here because it keeps its elongation — a balcony slab moves seasonally, and a coating that cannot stretch will split along the line of that movement.
Sectional-title balconies are usually common property even though only one owner uses them, which makes the repair a body corporate matter. We quote in a format that works for a trustee meeting, with the scope and exclusions itemised.
Common questions
How much does balcony waterproofing cost?
About R450–R800 per m² including membrane, screed correction and a tile or trafficable finish. Stripping an existing failed tile bed is additional.
Can you waterproof a balcony without lifting the tiles?
Only with a surface-applied trafficable coating over the existing tiles, which works when the tiles are sound and well bonded and raises the finished level. Where the bed underneath is already saturated it is a delaying tactic.
Who pays for balcony waterproofing in a sectional title scheme?
In most South African schemes the balcony slab and its waterproofing are common property and therefore the body corporate's responsibility, even where the balcony is for the exclusive use of one section. Check your scheme's rules and conduct rules — exclusive-use provisions vary.