The evidence
Fourteen photographs from the survey, exactly as taken.
High readings had been flagged ahead of a sale. Every high reading was real. None of them was water. This is the whole survey, published in full with the owner's permission.
The owner had already had the property surveyed. That survey reported several areas of damp, graded at its most severe level, and the buyers were understandably alarmed. Nobody could make sense of the results, because there was nothing to see: no staining, no tide marks, no mould, no smell.
We were asked for an independent opinion, with the sale live.
A detached converted barn. The original walls are of solid construction and predate the conversion. A later extension of cavity construction is not involved in any of the areas surveyed. Solid concrete ground floor. The inspection was carried out in light rain.
The hallway, bedroom 1, the utility room and the porch were surveyed in full, with bedroom 2 as the comparison room, and the rear elevation was inspected externally.
Before a single reading is taken in a problem area, we take a control reading: the same meter, on the same day, on the same construction, somewhere in the building known to be dry. Everything else is measured against that number.
Here, every control reading in every room came back Lo, meaning below 6 %WME, the bottom of the instrument's range. That single fact is what makes the rest of the survey readable. Without it, a reading of 38 is just a number that can be made to mean whatever the person holding the meter wants it to mean.
| Measured | Result |
|---|---|
| Control reading, every room | Lo, below 6 %WME |
| Air temperature | 22.6 to 24.1 °C |
| Relative humidity | 55 to 57% |
| Dew point | 13.6 to 15 °C |
| Coldest surface, each room, above dew point | 6.5 to 10.4 °C |
| External ground level below the damp proof line | 160mm |
No surface anywhere in the property was within 6 degrees of the dew point, so no condensation was occurring. There is no mould in the building.
Against that background there were a small number of high readings, and they shared one characteristic. Each was confined to a point, with dry material immediately beside it.
| Where | Reading | Immediately beside it |
|---|---|---|
| Porch, foot of the original external door frame | 59.8 %WME | 8.2 %WME, 100mm away |
| Hallway, foot of a door frame at an original threshold | 38 %WME | Control, either side |
| Utility room, foot of the doorway | 26.8 %WME wall, 22 %WME brick threshold | Floor beside it: Lo |
| Bedroom 1, rear wall, skirting row centre | 38 %WME | Rest of the row at control |
| Bedroom 1, rear wall, 600mm left | 44 %WME | Rest of the row at control |
That is not what water does. Water spreads. A wall wet from the ground gives a continuous band, highest at the skirting and falling with height. A wall wet from outside gives a patch with a diffuse edge. Neither produces a reading of 59.8 with 8.2 a hand's width away.
What does produce that is hygroscopic salt in the plaster. Nitrates and chlorides accumulate where moisture has evaporated out of a wall over many years. They conduct electricity, and they pull moisture out of the air around them. A resistance meter reads them as high and has no way of telling you it is reading salt rather than water.
The original openings of a former agricultural building are exactly where those salts sit. When the barn was converted they were plastered over. The meter is finding them, and the paint lifting at the foot of each frame is the salts pushing through the finish rather than damp.
Naming what a survey excluded is as useful as naming what it found, and a good deal more reassuring. Every mechanism was tested against the readings.
Fourteen photographs from the survey, exactly as taken.
The property is dry. It has no rising damp, no condensation, no mould and no evidence of a leak, and the only visible damage anywhere is paint lifting at the very foot of three old door frames.
The high readings that exist are confined to those thresholds and to two isolated spots on the rear wall of bedroom 1, and their shape, a very high number with dry material a hand's width away, is the signature of hygroscopic salts in the plaster rather than of moisture. That is what would be expected at the original openings of a former agricultural building, and it does not affect the building's condition beyond the finish on the plaster at those points.
Rake out and repoint the blown mortar on the rear elevation, before next winter. It is a defect in the external face whatever the readings inside mean, and it is the only route by which water could reach the two high spots in bedroom 1.
Everything else is cosmetic and optional. The lifting paint at the three thresholds, and the two hollow spots in bedroom 1, can be cut back and replastered with a system suited to salt contaminated backgrounds if and when an occupier wants a lasting finish there. There is no need to do it and no harm in leaving it.
Do not have the property damp proofed on the present evidence. A damp proof course, tanking or chemical treatment would address a problem this property does not have.
The report records this as highly probable on the evidence, not confirmed, and says what would close the gap: a drilled sample from each high point, tested for moisture content by calcium carbide and for nitrate and chloride salts. Salts with a low moisture content confirms the diagnosis. Moisture without salts in bedroom 1 would point to the blown mortar outside, for which the repointing already recommended is the remedy.
That is entirely at the owner's discretion, and the natural moment is when the plaster at those points is cut back for redecoration, since the wall is open anyway. A free inspection cannot afford to leave a question open like that. An independent one can, and it is the reason the report survives being read by somebody who disagrees with it.
Rory speaks sense!! We couldn't understand the results. Rory came along and explained it wasn't damp but picking up salt deposits. He wrote a fantastically detailed report... The report was written and sent the same day. Amazing service from a very knowledgeable professional man. Highly recommended. Google review, September 2026. Abridged. The full review is on our Google Business Profile.
We never comment on another surveyor's report inside our own. What any other survey concluded is a matter between the client and whoever wrote it, and a report that strays into it is worth less, not more, to anybody who later has to rely on it.
Fixed fee from £350. We carry out no remedial work, sell no products, and take no commission or referral fee from anyone who carries out repairs.
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