Balcony Tiling And Drainage

Balconies leak more often than any other part of an apartment, and the leak shows up in the unit below rather than on the balcony itself.

By the time it is visible, the water has usually been getting in for a long time.

The tiles are not the waterproofing

This is the misunderstanding that causes most of the damage.

Tiles and grout are not waterproof. Water passes through grout, and it always has. The waterproofing is a membrane underneath, and the tiles are a wearing surface sitting on top of it.

So a balcony that is leaking does not have a tile problem. It has a membrane problem, and re-grouting it is a temporary result that hides the cause for another year.

Where balconies actually fail

The junction between the floor and the wall. Movement happens here, and a membrane that was not properly detailed and reinforced at this junction cracks. This is the single most common failure point.

The drainage outlet. The membrane has to be dressed into the outlet so water on the membrane can leave. Where it stops short, water sits on the membrane and finds the nearest weakness.

The threshold at the door. The step down from inside to the balcony has to be sufficient, and the membrane has to run up under the door frame. Where the level is too close, water blows in under the door in a storm.

The edge and the balustrade fixings. Every bolt through the balcony slab for a balustrade post is a hole through the waterproofing. Sealed properly it is fine. Not sealed, it is a direct path.

Fall. A balcony has to shed water toward the outlet. One that is flat, or that falls back toward the building, will hold water permanently, and standing water finds every weakness eventually.

The drainage that gets forgotten

Most balconies have a floor waste. A lot of them also need a drainage layer at the membrane level, so water that has passed through the grout can escape rather than sit in the tile bed.

Where that is missing, the tile bed stays saturated. The consequences are efflorescence coming through the grout, tiles debonding, and constant moisture against the building.

Outlets also block. Leaves, dirt and general debris fill them, and nobody checks them until there is water inside. A balcony outlet is worth clearing on the same cycle as the gutters.

Why patching does not hold

Re-grouting, sealing the perimeter with silicone, or applying a coating over existing tiles all address the top layer.

They can buy time on a minor issue. They do not fix a failed membrane, because the membrane is under everything.

A proper repair means lifting the tiles, removing the bed, reinstating the membrane with the junctions and the outlet detailed correctly, flood testing it, and re-tiling. That is a real job and it is the only version that lasts.

Flood testing is the step people skip

Once a membrane is complete and before anything goes on top of it, the balcony is plugged and flooded and left for a period, and the unit below is watched.

It is the only opportunity to find a fault while it is still cheap to fix. Skipping it means the test happens after the tiles are down, using the neighbour's ceiling.

In a strata building

The slab and usually the original membrane are common property. The tiles on top frequently are not.

That split is why balcony repairs stall, and why the report identifying exactly where the failure sits matters more than the quote.

We do these as one job across tiling and waterproofing and building, including the flood test and the ceiling below where it has been damaged. If a balcony in a building you manage is leaking, send us what you know.