Correspondence: Lisbeth M. Ottosen, Department of Civil Engineering, Building 118, Technical University of Denmark, Lyngby 2800, Denmark; Tel: +45 45 25 22 60; Fax: +45 45 88 32 82; E-mail: lo@byg.dtu.dk

¹is Associate Professor at Department of Civil Engineering, Technical University of Denmark (DTU). She obtained a PhD in remediation of heavy metal polluted soil using an applied electric field (in 1996, Department of Geology and Geotechnical Engineering & Department of Physical Chemistry, DTU) and her research focus has since then been laid on the utilisation of electrokinetic transport processes in civil and environmental engineering. She is the author of more than 50 scientific journal papers.

²is an experienced researcher within the field of utilising electrochemical transport mechanisms for removal of contaminants from porous materials. She obtained her PhD from the Department of Civil Engineering, Technical University of Denmark, on the topic: 'Electrochemical removal of heavy metals from fly ashes' (2002), and during 2002–2006 she worked as research assistant professor at the department, still focusing on utilising electrochemical transport processes in environmental and civil engineering.

³is a PhD student at Department of Civil Engineering, Technical University of Denmark (DTU). In 2002 she started to work with electrochemical transport processes (master project) as a method for water transport in building materials. During 2002–2004 she was working as an assistant researcher in the field of electrochemistry applied on soil and building materials. Since 2004 she has been working on her PhD project, which focuses on ion transport in building constructions by use of electrochemistry.

Received 22 June 2007; Revised 22 June 2007.

Abstract

When newly plastered masonry facades show dark moist areas at a certain height or the plaster is loose from the masonry, the problem is often linked to increased salt content within the masonry. In the first case, the salts result in hygroscopic moisture and in the latter the salts are precipitating in the interface between the plaster and the masonry resulting in the plaster loosing adhesion. High salt concentrations can further result in salt weathering of masonry where the brick and/or mortar are/is seriously damaged. There is a lack of proven methods for the removal of salts from masonry. In the present paper, it is shown in laboratory and by a small pilot test that it is possible to remove the salt by applying an electric DC field to the masonry. Very low salt concentrations can be obtained in the laboratory, but the method needs further development before it can be used in actual buildings. The pilot test did show that salts can be removed from real salt contaminated masonry.