ABSTRACT
A dielectric probe developed for vertical soil moisture measurement was adapted for horizontal use in solid brick masonry. Historic masonry walls are exposed to rising damp at ground level or wind driven rain. Several methods are used to establish a horizontal damp proof course or a vertical water protection. The use of chemical damp proofing in historic buildings has in particular been much disputed in Denmark and elsewhere. But the effect of the treatments is difficult to control on site, and failures are not easily detected. The wall thickness of historic masonry is usually 50-100 cm, so moisture measurements at the surface do not give valid information about the conditions inside the wall. The ionic content of the pore water will severely disturb the signal of most moisture meters and make surface measurements unreliable.
