Observations of three-dimensional salt distribution in building sandstone

Observations of three-dimensional salt distributions within three sandstone blocks after 120 years of exposure in an aggressive urban environment are presented, based on measurements of soluble ion concentrations. Results ind icate a complex distribution of sulphur and chloride, where distributions a re not consistent between salt types, dictated by conditions at the six sur faces of the blocks. This highlights the dangers of extrapolating the resul ts of salt weathering simulations with regard to salt accumulation patterns , or the results of fieldwork which rely on single-surface samples from ind ividual stones. The widely held perception that urban environments are 'dry ' with shallow surface wetting of building stone does not appear to hold tr ue for certain building stone. Copyright (C) 2000 John Wiley & Sons, Ltd.