LARSEN, POUL KLENZ1

1) Senior consultant, The National Museum of Denmark, poul.klenz.larsen@natmus.dk

A dielectric probe developed for vertical soil moisture measurement was adapted for horizontal use in drilled holes equipped with access tubes. A cavity along the access tube gave a substantial error on the reading, so the drilling of the holes needed to be accurate. The instrument should be used to detect differences in water distribution and changes in water content over time. The horizontal moisture profiles indicated the source of water to the walls, and the change in water content over time proved the effect of different treatments against rising damp. A chemical damp proof course or a horizontal moisture membrane may not seem to be very effective, because it takes many years for the masonry to dry out by evaporation. The individual response may depend on the different exposure to rising damp and driving rain. The dielectric probe is a reliable instrument for long term monitoring of water content in solid masonry walls.

Keywords: water content, dielectric probe, solid brick masonry, rising damp, driving rain