Fungus, Mould & Algae

What causes it

Black or green growth on damp internal walls — a health concern as much as a cosmetic one, and always a symptom of moisture.

Mould is a symptom with a very specific cause: a surface that stays wet long enough for spores to establish. Find why the surface is wet and the mould problem is solved; bleach it without doing that and it returns within weeks.

• Condensation — the dominant cause in Pune flats. Warm humid air meeting a cold surface. The signature is black spotting concentrated on external corners, behind wardrobes and furniture pushed against outside walls, on window reveals, and on ceilings below an exposed roof. It is worst in rooms that are closed up and unventilated.
• Inadequate extract ventilation in bathrooms and kitchens, which puts large volumes of moisture into the flat with nowhere to go — made worse by drying laundry indoors through the monsoon.
• A genuine leak or seepage keeping plaster saturated. Here the mould follows the shape of the damp patch rather than the cold spots.
• Rising damp, with mould along the skirting line.
• Cold bridging at RCC columns and beams, where the concrete runs colder than the surrounding masonry and condensation forms in a straight line that traces the structure.

The distinction that matters: mould on cold spots and corners is a ventilation and insulation problem; mould in a defined patch is a water problem.

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 diagnose before we remediate, because the two causes need opposite treatments and sealing a condensation problem makes it worse.

Surface and deep moisture readings are compared — condensation reads wet at the surface and dry behind, a leak reads wet through. Thermal imaging maps cold bridging and shows whether the pattern follows the structure or follows a water path. Where relevant we look at internal humidity, extract provision and how the rooms are actually used.

• Where it is condensation — extract ventilation sized properly for the bathroom and kitchen and vented outside rather than into a shaft; insulation or an internal thermal upgrade at the cold surface to lift it above dew point; and practical changes such as not drying laundry in a sealed room. This is the honest answer and it is not a waterproofing contract.
• Where it is a leak or seepage — the source is treated first as set out on our water leakage and wall seepage pages, then the wall is made good.

Remediation itself: affected material removed rather than painted over, the substrate treated with a fungicidal wash and left to work rather than wiped straight off, salt- or mould-contaminated plaster cut back and replaced with a renovating render, and redecoration only after the substrate reaches a measured dry reading. Anti-fungal additives in the finish coat help, but they manage the symptom — the ventilation or the leak is what actually fixes it.

What it costs

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