Water running down the balcony and facade – causes and solutions

Dark streaks on the facade, green deposits under the balcony or spalling concrete at the edge almost always have the same cause: rainwater is not drained cleanly at the balcony edge.

The 5 most common causes

1. No drip edge or one that is too short. Without a drip nose, surface tension makes water run around the edge and along the underside.
2. Too little slope. Standing water penetrates the joints. About 1.5–2 % slope towards the edge is usual.
3. Leaking joints and corners. Without connectors and sealing tape, water enters the build-up at profile joints.
4. Waterproofing not connected to the profile. Water flows under the covering to the edge and comes out at the front face.
5. Blocked gutter or missing outlet. The gutter overflows and water runs down the facade.

The solution: edge profile with drip edge

A suitable aluminium drip edge profile forms the end of the waterproofing and lets water drip freely in front of the face. Joints are made with connectors, corners with prefabricated corner pieces and wall junctions with wall end pieces – leaving no open spots.

Do I have to renovate the whole balcony?

Not necessarily. If the surface is intact and only the edge is affected, replacing the edge tiles with a new profile is often enough – see retrofitting a drip edge. If tiles are hollow or loose over large areas, a full balcony renovation is worthwhile.