Services / Damp Surveys

Diagnosing Damp

There are three main causes of dampness in a building:

  • Rising damp
  • Penetrating damp
  • Condensation damp

However, it could also be caused by the presence of hygroscopic salts, the result of leaking or burst pipes or other accidental damage and these all need to be taken into consideration when investigating damp.

Scientific analysis can help diagnose a damp problem but the importance of sight, feel and smell should not be undervalued. Tests include the use of electrical resistance and capacitance meters, on-site moisture testers, hygrometers and salt analysis.

Moisture meters can help determine the presence of moisture in a building but they can’t diagnose damp on their own. When investigating damp, the survey should be a process of elimination. The following is a basic guide to the on-site survey procedures that should be followed to eliminate sources of water ingress:

External examination of:

  • Roof covering.
  • Chimneys and flashings.
  • Condition of brickwork, stone, mortar, plinths, render, weatherproof finish etc.
  • Flat roofs.
  • Joinery.
  • Rainwater goods.
  • Wall construction, cracks in masonry/render.
  • High ground levels, abutting gardens or walls.
  • Position/condition of existing or remedial DPC installation.

Internal search for:

  • Damp/wet patches, water droplets
  • Plaster & paint deterioration, blistering, appearance of stains & salts.
  • Rotting or mouldy skirting boards or other joinery.
  • Effloresence.

Internal examination for:

  • Solid or timber floors (lifting floorboards if possible to examine subsite), including the floor/wall junction.Solid or timber floors (lifting floorboards if possible to examine subsite), including the floor/wall junction.
  • Moisture content of timber skirting using electrical moisture meter. • Any new plasterwork, height of re-plastering, its condition and type.
  • Any remedial DPC installation, including position and depth of holes (if inserted from inside).
  • Plumbing – check for defects.
  • Internal walls – using electrical meter to note the pattern of any moisture readings.
  • Ventilation, including sub-floor ventilation, trickle vents and extract vents.

Additional information required:

  • History and use of property including number of residents.
  • Lifestyle of residents i.e. use of central heating or other heaters, method of clothes drying, washing and cooking, use of vents etc.

Once all potential causes of damp have been considered a conclusion can be reached and recommendations made.

If you have damp but are not sure why and what to do about it, contact us and we will be to arrange an investigation for you.


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