Damp investigations

Stage 3: detailed investigation

Additional equipment for stage 3

  • Carpet stretcher.
  • Borescope.
  • Flooring saws and jig saws (for lifting tongued and grooved boards; only use in consultation with the client).
  • Drill and 6mm bit.
  • Scraper (for removing surface depositions or plasters).
  • Metal detector for locating metals - pipes, cables, foils, etc.
  • Old 35mm film cases for samples and self-adhesive labels.
  • Full damp diagnostic kit as supplied by major instrument maker including:
    • resistance meter (sometimes with a capacitance function in the same instrument);
    • capacitance meter;
    • deep insulated probes for resistance meter;
    • salts detector;
    • salts analysis kit;
    • relative humidity sensor (i.e. thermo-hygrometer);
    • surface thermometer;
    • means of calculating dew point (by moisture meter or sliding calculator);
    • hammer electrode;
    • humidity box (used with a humidity sensor); and
    • listening stick (stethoscope).

When you need to proceed to stage 3, be prepared to use any or all of the tests and equipment listed above in pursuit of an explanation for the dampness you have observed at stage 2. These tests and equipment – including hole drilling, using deep wall probes, conducting salts tests, and taking relative humidity readings – are described fully in Surveying equipment and tests.

For an average 3-bedroomed house you need to allow at least 1 hour extra on site, plus some time to carry out tests or analysis back at the office. You may also need to send samples off for testing at a laboratory, although this is relatively expensive, so you would benefit from learning to conduct the tests yourself.