Damp patches on internal walls have a short list of causes — but the treatments are completely different, and the most commonly sold one (injected damp proofing) is very often not the answer. Before paying for treatment, it is worth understanding what each type of damp looks like.
Condensation — the Most Common by Far
Black spot mould in corners, on cold external walls and behind furniture, worse in winter, often paired with streaming windows: that is condensation, and it is a ventilation and heating issue, not a wall failure. No injection cream fixes it. Extractor fans, trickle vents, drying washing outdoors and modest background heat usually do.
Penetrating Damp — Water Getting In Sideways
Patches that appear or darken after rain, often at chimney breasts, around windows or on exposed elevations, point to water penetrating from outside: failed pointing, cracked render, leaking gutters, or porous solid walls — extremely common in the North West’s Victorian stock. The fix is outside, not inside: repair the defect and let the wall dry.
Rising Damp — Rarer Than the Quotes Suggest
Genuine rising damp shows as a tide mark up to roughly a metre high on ground-floor walls, often with salts. It does happen — but it is diagnosed far more often than it occurs, usually by companies selling the treatment. Bridged damp courses, raised external ground levels and leaking pipes mimic it convincingly.
Get an Independent Diagnosis First
An independent damp survey by an RICS surveyor — with no treatment to sell — identifies which of these you actually have and what it will genuinely cost to put right. See our guide to damp survey costs, or call 020 4579 8270 for a fixed quote in Manchester and the North West.