Why is my building leaking?

The usual suspects

• Balconies: failed membranes, cracked hobs, blocked drains and poor falls
• Windows and doors: perished seals, missing sealant, faulty flashings
• Facades: cracked render, failed movement joints, penetrations
• Roofs and parapets: lifted flashings, blocked box gutters, failed cappings
• Planter boxes: failed membranes draining into the slab below

How water testing works

1. Inspect the likely sources from outside, often by rope access for upper floors.
2. Test one element at a time (a window, a joint, a balcony) with controlled water.
3. Monitor inside for the leak to appear, confirming or ruling out each source.
4. Document findings with photos and recommend a repair.

Fix the cause, not the stain

Painting over a ceiling stain or adding silicone in the wrong place just hides the problem. Once the source is confirmed, the repair might be as simple as resealing a window, or as involved as replacing a balcony membrane. See water testing & waterproofing and leak detection by rope access.