What independent damp surveys actually find

The homeowner had damp patches low on the internal walls of their front bedroom and living room. Two separate damp-proofing companies had visited and both quoted for a chemical injection damp-proof course — total estimates ranged from £1,800 to £2,600, plus replastering.

Moisture readings were elevated at low level, but the pattern was inconsistent with rising damp. The affected walls were external-facing. The property had no working extract ventilation in the kitchen or bathroom. Thermal imaging showed cold bridging around window reveals. No failed DPC was identified.

Interstitial condensation and surface condensation, not rising damp. Warm, moisture-laden air from cooking and bathing was migrating through the property, depositing moisture on cold wall surfaces. The low-level pattern mimicked rising damp — a common misread on a standard moisture meter without wider assessment.

A Level 2 RICS HomeBuyer Report flagged damp in the rear ground-floor rooms and recommended further investigation by a specialist. The buyer's solicitor stalled the exchange pending clarification. The seller had invested in the property and was unwilling to renegotiate without evidence.

Moisture readings at low level on the rear wall were marginally elevated. External inspection revealed a recently blocked airbrick beneath the rear extension. The sub-floor space had no active ventilation. No active water ingress was identified. The original DPC was intact.

Restricted sub-floor ventilation causing elevated humidity in the floor void, which was being absorbed into the base of the plasterwork. Not rising damp, not penetrating damp. The airbrick had been inadvertently blocked during recent paving works.

Persistent damp at low level on the internal front wall of a Victorian mid-terrace. The homeowner had tried repainting with waterproof masonry paint twice. The problem returned within months each time. A neighbour had had damp-proofing injected for a similar issue several years earlier and was still having problems.

External inspection revealed that the front garden had been raised over successive years — soil, new paving and a concrete border had brought the external ground level to within 25mm of the internal floor level, bridging the original DPC by approximately 120mm. The internal plaster was standard gypsum — not suitable for a damp environment.

DPC bridging from raised external ground levels. Genuine moisture was entering the wall at the point where the DPC had been bypassed. Chemical injection would not have addressed this because the DPC itself was intact — the problem was external ground levels bypassing it entirely.

A damp stain had appeared on the internal face of the chimney breast in the first-floor bedroom, roughly two-thirds of the way up the wall. It had been progressively worsening over two winters. A previous inspection by a general builder had suggested the brickwork needed repointing externally.

Repointing had been completed but the staining had returned. Roof inspection (using a ladder) revealed that the lead flashing at the roof-to-chimney abutment had partially lifted and pulled away from the mortar chase. Rainwater was tracking down between the chimney stack and roof surface, entering the chimney void and migrating internally. Brickwork moisture readings were largely normal at wall level.

Roof abutment water ingress via failed flashing. The moisture was travelling down the internal chimney structure and presenting on the internal face as a mid-height stain — easily misidentified as penetrating damp through the brickwork. Repointing had been irrelevant to the actual source.

A tenant in a first-floor flat had reported mould growth on bedroom walls and ceiling, and in the bathroom. They had written formally to the landlord asserting the property was structurally damp and requesting urgent remediation. The landlord believed the problem was condensation-related and was concerned about the threat of a formal disrepair claim.

Mould was present on north-facing walls in the bedroom and in the upper corners of the bathroom. Moisture readings on the walls were largely dry behind the visible mould — consistent with surface condensation rather than structural moisture. The bathroom extract fan was non-functional (a broken pull cord). The kitchen had no extract ventilation at all. The bedroom window was sealed shut with paint.

Chronic condensation from inadequate extract ventilation and restricted natural ventilation. The property had no meaningful means of removing moisture-laden air produced by bathing and cooking. The mould was a symptom of moisture accumulation in the air, not water ingress through the structure. The landlord was responsible for maintaining functional extract ventilation — the broken fan was a maintenance failure.

A buyer was purchasing a 1970s cavity wall property that had cavity wall insulation installed approximately ten years prior. A HomeBuyer Report flagged elevated moisture readings on the kitchen and utility room external walls but provided no diagnosis. The buyer wanted to understand whether the insulation was causing the problem before proceeding.

External walls showed targeted moisture in specific zones, with dry areas immediately above and below. Thermal imaging identified cold spots consistent with voids in the cavity insulation fill — areas where insulation had settled, leaving unfilled sections. A borescope inspection through a drill hole in the mortar course confirmed insulation debris had collected at multiple wall tie positions, creating physical moisture bridges across the cavity.

Cavity wall bridging at wall tie positions, exacerbated by insulation debris accumulation. Moisture was being physically carried from the outer leaf to the inner leaf across the debris bridges. The cavity insulation installation appeared to have been poorly controlled, leaving material draped across ties rather than evenly distributed.