External wall waterproofing for Singapore's climate.

External walls take the worst of Singapore's weather — driving monsoon rain at the windward face, daily UV, and thermal cycling that opens and closes hairline cracks every afternoon. External wall waterproofing is the boundary between that and a dry interior. Done well, one system lasts 10–15 years and protects the paint, the plaster, the slab and the rebar all at once.

Why external walls in Singapore leak.

Wall seepage is Singapore's most under-diagnosed waterproofing problem. A damp wall in the bedroom, peeling paint behind a cupboard, a musty smell that won't go away — these are all symptoms of water travelling through the external wall from outside. The source could be hairline cracks in the render, failed sealant around window frames, or degraded paint film that no longer sheds water. Because the water enters from the facade and tracks inward through the masonry, a damp wall on the inside is almost always a waterproofing problem on the outside. Repainting the interior will not fix it. Facade waterproofing — crack injection, sealant re-bedding and elastomeric coating on the exterior — is the only way to stop wall seepage at the source.

In ground-floor and plinth-level areas, rising damp can contribute to interior dampness — moisture wicks upward through the wall by capillary action, bringing dissolved salts that crystallise on the interior surface. Where the issue is rising damp rather than rain penetration, the treatment is a different specification: a physical or chemical damp-proof course, not a facade coating.

Persistent mould on an interior wall that returns after cleaning is almost always a sign of moisture travelling through the external wall from outside — not a ventilation problem. Solving the mould wall means solving the external waterproofing.

• Hairline cracks at construction joints and openings. Thermal movement opens them. Driving rain pushes water in.
• Failed paint film. Standard paint isn't waterproof — once the elastomeric layer fails, water tracks straight to the plaster.
• Parapet upstand and capping failure. Water sits on the capping, finds the crack, and enters laterally.
• Window and AC sleeve detailing. Sealant beads age out after 5–7 years. The opening becomes a funnel.
• Render delamination. Where cement render has lost bond, water travels behind it and surfaces somewhere far from the entry.
• Persistent interior symptoms. If your interior wall leak repair keeps failing — peeling paint on an external-facing wall that returns after every monsoon, wall dampness that no amount of interior repainting fixes — the problem is almost certainly on the exterior side. The fix is facade waterproofing, not another coat of interior paint.

System options.

Standard scope.

1. Façade survey — full walk-down with photo log of every crack, stain, render hollow and sealant defect.
2. Pressure-wash and dry-out.
3. Crack treatment — rout out, prime, fill with PU sealant or inject as required.
4. Render repair — hack hollow render, replaster with polymer-modified mortar, cure.
5. Primer.
6. Elastomeric base coat — full coverage, wet-film thickness logged.
7. Elastomeric top coat — perpendicular pass.
8. Sealant re-bead at all window perimeters and AC sleeves.
9. Spot rain-test at known entry points.
10. Photo report, signed warranty.

Access methods.

Façade access is half the cost on a high-rise. We work all three access methods:

• Scaffold — for landed homes up to 3 storeys and most low-rise condos. Safest for heavy prep scopes.
• Gondola — for high-rise condos and commercial blocks with parapet anchor points.
• Rope access (industrial abseil) — for spot repairs and slim-access elevations where scaffold isn't viable. IRATA-trained crew.

External wall waterproofing FAQs.

Related pages: Façade painting · Rooftop & parapet · Building repair