Historic Salts Misdiagnosed as Active Damp – Bishop Auckland Case Study
This case study documents an independent damp survey carried out at a residential property in Bishop Auckland, County Durham. The inspection was requested after persistent damp readings were identified internally and active damp was suspected despite no visible source of ongoing moisture.
Property Background
The property is a traditional masonry-built house located in Bishop Auckland. Internal plaster at low level showed visible staining and elevated moisture meter readings, leading to concerns that an active damp issue was present. The homeowner sought an independent damp survey to confirm whether damp proofing work was genuinely required.
Initial Diagnosis Provided
Prior to our inspection, the damp symptoms were attributed to ongoing moisture ingress based on persistent meter readings within internal plaster. No consideration had been given to the age of the property or the potential presence of historic contamination within wall finishes.
Independent Damp Survey Findings
A full independent damp survey was carried out using calibrated moisture testing equipment, visual inspection, and external assessment of the building envelope. Moisture readings were found to be localised rather than uniform, which is inconsistent with true rising damp.
External inspection identified defects in pointing and masonry allowing moisture penetration. Internal readings were influenced by historic plaster contamination rather than active moisture rising from the ground.​
Independent Damp Survey Findings
An independent damp survey was undertaken, incorporating moisture testing, surface inspection, and assessment of internal wall finishes. Moisture meter readings were elevated within the plaster but showed no evidence of active moisture movement within the masonry itself.
The findings were consistent with hygroscopic salts retained within historic plaster, which attract moisture from the air and produce misleading damp meter readings even in the absence of an active damp source.
Diagnosis Outcome
The damp readings present within the property were not caused by active damp. The inspection confirmed that historic salt contamination within the internal plaster was responsible for the moisture readings, rather than ongoing moisture ingress.
No damp proof course installation or structural damp treatment was required.
Recommended Action
Targeted internal remedial measures were recommended to address the contaminated plaster, including appropriate removal and replacement where necessary. By resolving the historic salt contamination, false damp readings could be eliminated without unnecessary damp proofing work.
Why Historic Salts Are Commonly Misdiagnosed
Historic salt contamination is frequently misdiagnosed as active damp due to persistent moisture meter readings. Without understanding how hygroscopic salts behave within older plaster, incorrect conclusions are often drawn. Independent damp surveys ensure that historic materials and finishes are properly assessed before remedial work is specified.
Related Damp Survey Services
This inspection was carried out as part of our independent damp survey service across County Durham. We regularly investigate damp problems that are misdiagnosed as rising damp, penetrating damp, or condensation and mould related issues.
Book an Independent Damp Survey in Bishop Auckland
If you are experiencing persistent damp readings within a Bishop Auckland property and require confirmation before committing to remedial work, an independent damp survey provides accurate diagnosis and clear recommendations.