After the Survey on a Period House

You have received the survey of the period house you want to buy and it is full of doom and gloom.

Take a deep breath, relax, and understand that most surveyors will be careful to cover their backs; their professional future depends on it and house problems are often difficult to diagnose. Furthermore, in the time available, he or she cannot investigate a problem fully - to determine the seriousness of it or indeed the cause.

Here is an excerpt from a typical survey:

There is evidence of dampness to ground floor walls. Timbers in contact with them may be defective. Further investigation is required to know the full extent of any damage.
The damp proof course is bridged and may not be fully effective. You need to lower the external ground level to 150mm below the level of the damp proof course.
Sub-floor ventilation is inadequate which may have allowed defects to occur. You should instruct a specialist to investigate the full extent of the defect and carry out the necessary repair work.
Instruct a specialist to evaluate the need for a new damp-proof course (DPC).

Let us review this point by point.

The moisture meters used by most surveyors are not helpful. Individual meter readings are worthless when it comes to assessing damp. Electronic moisture meters are designed to work on wood only; they do not give accurate readings on brick, stone or plaster. Hydroscopic salts or condensation will produce artificially high values. However, these meters can be used for profiling; this means taking a large number of readings at different points on the wall (vertically and horizontally) and then plotting graphs from the readings. Different damp and/or salt configurations produce different profiles. If you can borrow a meter, test the ground floor joists; a moisture content of less than 15% is satisfactory. Alternatively, have a feel around the walls inside, low down. Do they feel damp or much colder than higher up? Is wallpaper or paint discoloured, peeling or powdery? Sniff (literally) round the bottom of skirtings and between any exposed floorboards. Is there any mushroomy smell? Bounce on the floors close to outside walls. Do they give? If you answer "yes" to any of these then it would be worth taking up a board if the seller would allow it to look underneath. If not, factor in say, £500 per room in your sums.
This is recommended; if it is just soil then a few hours' digging will do the trick.
As long as existing airbricks are not blocked, then nothing should need doing. In, say a long thing house, there should be airbricks at the narrow ends - two at each ideally, but obviously not where there are solid floors.
You really want an independent specialist - not a damp treatment company. Unfortunately, these are relatively scarce. The obvious option is to go ahead and get a chemical DPC, but these are rarely as effective as promised. Most old walls have some rising damp in them but only for one or two courses of brick. However, in many cases excess moisture levels are caused by other factors such as high external ground levels, poor drainage from adjacent tarmac or paving, inadequate ventilation etc. It is more cost-effective to make sure that these causes of the damp are eliminated first before, for example a new damp-proof course (DPC). Our section on damp gives more detail.

The survey may also comment on signs of woodworm; again this needs independent advice from an expert with more time to discover whether the infestation is active.

The surveyor is often not saying that there is a definite problem; only that there may be one, and indicating the likely remedial action that would be needed. The sad conclusion is that by getting these 'problems' documented and drawn to the attention of the mortgage provider, the prospective buyer is cajoled into spending money on immediate work which may be un-necessary and inappropriate.

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