Terrace Leakage Problems

What causes it

Water staining the ceiling below your terrace, usually from failed coating, cracked screed or blocked drainage outlets.

Open up a leaking terrace in Pune and the field of the slab is usually sound. It is the interruptions that fail:

• The parapet junction. The 90° angle where slab meets parapet is a movement joint whether or not it was designed as one. A coating taken straight round the corner with no fillet and no reinforcement cracks there first. This is the single most common terrace entry point we find.
• Rainwater outlets. The membrane has to be dressed into the outlet body. A coating that stops at the rim leaves the most water-loaded 100 mm of the terrace untreated.
• Penetrations. Tank supports, railing posts, dish and solar mounts, conduit — each one a hole through the waterproofing.
• Ponding from no fall or a reverse fall. Water standing 48 hours after the rain stops is the clearest predictor of early failure we see. Common on older buildings and on terraces re-tiled once or twice.
• Old cracks that were painted over. A structural crack bridged by a coating rated for less movement reopens in the first hot season.

The pattern below tells you a lot: a leak at one corner points to a junction; a leak in several rooms at once points to ponding or a failed field; a leak that never stops is not the terrace at all.

How we identify the real source

Water travels. The stain on a ceiling is frequently metres from the actual point of entry, which is why we deep-scan the structure before recommending treatment rather than working from the visible damage alone.

How we treat it

The first decision is repair versus replace, and it is an honest test rather than a sales pitch — what proportion of the surface has failed, and is the existing layer still bonded?

• Localised failure, sound elsewhere, layer well bonded — targeted repair at the junctions and outlets, then an overcoat. Lowest cost, and appropriate more often than the industry admits.
• Widespread debonding or several previous layers — strip and rebuild. Overcoating a delaminated layer buys one monsoon, then fails with the old layer underneath it.
• Ponding from a reverse fall — a screed laid to a fall before anything waterproof goes on top. No coating solves this, and it changes the price materially. We would rather say so at inspection.
• Tiled terrace, tiles sound and bonded — a system designed to go over tiles avoids demolition. If they are drummy they are trapping water and must come up.

Systems run from acrylic elastomeric at roughly ₹55–95 per sq ft through PU membranes at ₹110–200, with APP/SBS torch-applied where a robust thick layer under a screed is right. Judge on cost per year of service life rather than headline rate. Work is timed to finish before the second week of June or to wait until October, and the completed terrace is flood-tested with the ceiling below watched before the warranty certificate is issued.

What it costs

Use the cost calculator for an indicative range, or book a free inspection for a written estimate.