Terrace waterproofing before the monsoon: a checklist

Leaks rarely start in the rain; they start months earlier with hairline cracks and blocked drains. Use this checklist ahead of the monsoon.

1. Inspect

• Look for cracks, hollow-sounding patches and peeling coatings.
• Check parapet joints, pipe penetrations and the joint between floor and wall.
• Clear outlets and make sure water does not pond for more than a few hours after rain.

2. Repair

Open up cracks, clean them and fill with a crack filler or polymer-modified mortar. Treat the floor-wall joint with a fillet (cove) so the membrane can bend without cracking.

3. Choose a system

System	Best for
Cementitious coating	Bathrooms, water tanks, budget terrace work
Acrylic liquid membrane	Exposed terraces with moderate foot traffic
Polyurethane membrane	Long-life roofs, large temperature swings

4. Apply carefully

• Prime the surface, then apply at least two coats at right angles.
• Use reinforcing fabric at joints and corners.
• Allow full curing before protecting or loading the surface.