What should a proper damp survey include?

A proper damp survey should tell you where unwanted moisture is coming from, why it is affecting the building and what work is proportionate to that cause. It should consider the whole property, not just the stained wall, and explain the evidence behind its conclusion. A moisture meter reading or the word ‘rising’ on a form is not a diagnosis. The useful outcome is a clear account of what was found, what remains uncertain and what to do next.

Start with the building, not a treatment

RICS says a surveyor assessing moisture in a traditional building should take a whole-building approach, seek the source of excessive moisture, avoid relying on potentially misleading data and advise the client how to manage the situation. This means looking at how the affected room relates to the roof, outside walls, ground, plumbing, ventilation and any changes made to the building. The surveyor should use professional judgement rather than simply hand over a recommendation for somebody else to investigate.

It helps to tell the surveyor when the patch appeared, whether it changes after rain, and what work has already been tried. RICS notes that finding a moisture source can be complex and may require a methodical approach over time. A single visit may identify an obvious leak; a less obvious problem may need further inspection or observation. A useful report should make that distinction plain rather than present a guess as certainty.

Check the likely routes for moisture

A survey should follow the clues that fit your building. RICS lists roof defects, overflowing gutters and rainwater pipes, damaged pointing or render, raised ground beside walls, blocked floor vents, failed drainage and plumbing leaks among possible sources to check. A surveyor need not find every item on a generic list in every house, but should inspect relevant possibilities and explain why they do or do not fit the pattern seen indoors.

• Outside: look at roof coverings, gutters, downpipes, wall finishes, window and door edges, and whether ground or paving is high against a wall.
• Inside: follow the location of staining or mould, check nearby plumbing and note where ventilation or heating may be inadequate.
• Below and around the affected space: consider drainage, suspended-floor ventilation and any cellar or ground-floor details that could change how moisture moves.

The labels ‘penetrating damp’, ‘condensation’ and ‘rising damp’ describe ways moisture moves through or onto a building. They do not by themselves identify its source. A broken roof tile and a shower leak both introduce water, but the right repair is very different. The survey should connect the observed pattern to a plausible source, and it should recognise where more than one process is involved.

Use readings as evidence, not as the verdict

A damp meter can contribute useful information, especially when used appropriately in timber. RICS warns against diagnosing the source of damp in hard walls and solid floors from meter readings alone: other conductive materials can produce high readings. SPAB likewise warns that salts in old masonry can produce elevated electrical readings even when a wall is virtually dry. A careful surveyor should compare readings with visible signs, the construction and other possible moisture routes.

If rising damp is suggested, ask what evidence distinguishes it from rain penetration, condensation or moisture from another source. SPAB describes visible clues such as a tide mark, but cautions that rising damp is often misdiagnosed. It says tests within the wall thickness can help rule out surface condensation. You should be able to see the reasoning in the report. A bare meter reading followed by a recommendation for a new damp-proof course leaves the central question unanswered.

Expect a written explanation and proportionate recommendations

RICS advises people commissioning a survey to ask for an inspection in line with the Joint Position Statement on traditional buildings. Its consumer guide says a compliant report should give an unbiased professional opinion from someone without a commercial interest in selling a product, and suggest works proportionate to the property. That is a useful standard to ask about when choosing a surveyor, particularly where an earlier quotation recommends treatment before explaining the moisture source.

The report should identify the areas inspected, the clues observed, the likely source or sources, and the reason for the proposed work. It should distinguish urgent maintenance from longer term changes and say where evidence is insufficient. If the surveyor recommends a new damp-proof course, waterproof coating or other substantial intervention, ask why routine repairs and simpler causes were ruled out. RICS warns that damp-proofing measures can be inappropriate for some older solid-wall buildings and can make damp worse. SPAB also cautions against unnecessary retrospective damp-proof courses in old buildings.

Why Yorkshire and Lancashire stone homes need local judgement

In a Yorkshire or Lancashire stone terrace, a standard checklist cannot replace understanding how that particular wall, floor and drainage arrangement works. RICS advises choosing a building surveyor experienced in building pathology and says an experienced local surveyor will know local materials and construction methods. Ask what experience they have with solid walls and traditional buildings. Where a recommendation seems questionable, SPAB suggests a written second opinion from an independent chartered surveyor or consultant. That is especially useful before making changes that are difficult to undo.

For a homeowner, the next step is to commission a suitably qualified, independent surveyor when the source remains uncertain, the problem keeps returning or a major treatment is proposed without convincing evidence. For a tenant, report the damp to the landlord and ask what investigation supports the proposed repair. The goal in either case is simple: understand the water first, then choose work that addresses it and suits the building.

This page gives general information, not legal or medical advice. For your own situation, use the organisations listed under "Where this comes from" at the foot of the page.