Roof Leakage Problems

What causes it

Leaks through roof slabs, sheet joints and parapet junctions that reappear with every monsoon despite repeated patching.

Roof leakage divides sharply by construction, and the two types fail for almost opposite reasons:

• RCC flat roofs fail at the same points as terraces — parapet junctions, outlets, penetrations and old cracks — with the added problem that plant mounted on the roof (AHUs, tanks, dishes, solar frames) is usually bolted straight through a membrane nobody re-detailed afterwards.
• Metal sheet roofs fail at the fasteners and the laps. Each screw carries an EPDM washer that hardens and splits under UV; twelve to fifteen years in they fail as a population, not individually, which is why the leak appears everywhere at once and looks inexplicable.
• Gutters and valleys on both types. A gutter laid without fall, corroded at the laps, or with downpipes sized for the original building and not the extension added later will back water up over the lap and into the structure.
• Ridge and north-light glazing junctions — movement joints expanding and contracting across a long roof on a 40°C daily swing. Sealant alone here lasts single-digit years.
• Blocked outlets. Three months of concentrated Pune rain through a handful of outlets, and one blockage turns a functioning roof into a shallow tank.

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

We survey the whole roof plane rather than the reported leak, because on a roof the visible drip is nearly always downhill of the actual defect.

• Metal roofs — mechanical de-rusting to bright metal at laps and fastener heads, corroded fasteners replaced one-for-one with oversize fixings and new washers, then a liquid-applied PU or acrylic-polymer system taken over the fastener heads and dressed into the gutters, so roof and valley become one continuous layer with no termination in the wet zone. Reinforcing fabric is laid into every lap, ridge and valley.
• RCC roofs — grinding or shot-blasting to remove laitance and old coating, cracks cut out and filled, a fillet formed at every upstand, then a reinforced membrane with all penetrations individually detailed.
• Gutters — cleaned to substrate, falls corrected, capacity checked against the actual roof area, and lined rather than patched.
• Emergency work — leak-stopping and injection can be done in the monsoon; a full re-coat needs a dry substrate and an uninterrupted curing window.

Dry film thickness is recorded per bay and gutters are flood-tested before handover. On industrial sites we sequence in bays sized to your shutdown so nothing is left open across a shift change.

What it costs

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