Wall Seepage Problems

What causes it

Moisture travelling through external or shared walls, showing as patches, blistered paint and salt deposits inside.

“Seepage” covers three physically different problems that look almost identical on a wall and need completely different treatments. Getting this wrong is why so much money is spent on damp walls with no lasting result.

• Rising damp — groundwater drawn up by capillary action from a failed, bridged or absent damp-proof course. A tide mark at a fairly consistent height, typically under a metre, present all year, worst at skirting level, with salt deposits along the top edge.
• Lateral or penetrating seepage — water crossing the wall from outside. A patch rather than a band; it corresponds to something on the far face (a defective downpipe, open pointing, a planter bed against the wall, a neighbouring bathroom) and worsens within a day or two of rain.
• Condensation — not seepage at all. Room moisture condensing on a cold surface. Black mould on cold spots and external corners, worst in unventilated rooms, and a substrate that reads wet at the surface but dry behind.

A meaningful share of the seepage enquiries we take from Pune flats turn out to be condensation. Waterproofing it achieves nothing and often makes it worse by sealing the wall.

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 establish which of the three it is before quoting — surface and deep moisture readings compared, thermal imaging to map the pattern, and inspection of the opposite face of the wall in every case, because that is where the cause usually is.

• Rising damp — a silane/siloxane damp-proof cream injected at mortar-course level to form a continuous barrier through the full wall thickness, followed by a salt-resistant renovating render. The render is not optional: the DPC stops new water rising, the render manages the salts already in the wall. Doing only the first is why so many damp courses are believed not to have worked.
• Lateral seepage — correct the external cause first, then treat the water-facing side: crack repair, a cementitious or elastomeric coating, or a breathable silane/siloxane facade repellent from about ₹35 per sq ft where the masonry is sound. Where the outside face cannot be reached, a negative-side crystalline slurry.
• Condensation — extract ventilation, insulation of the cold surface and mould remediation. We say so and do not charge for waterproofing that cannot help.

Contaminated plaster is cut back at least 500 mm beyond the visible damp and salt line and removed from site. Replastered walls need roughly a month of drying per 25 mm before decoration — we state that on the estimate, because painting a drying wall traps the moisture and the treatment gets the blame.

What it costs

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