This paper discusses water penetration resistance studies on conventional brick/block masonry for variations in construction types and materials adopting ASTM E 514-90 procedure. The behaviour of interlocking block masonry for the influence of type of bedding (dry-stacking, thin-jointing, and mortar-bedding), surface finishes (stucco/plaster finish) have been investigated. Also the relative performance of solid as well as hollow interlocking block masonry system developed by the authors, with conventional masonry is reported. © 2003 Elsevier Science Ltd. All rights reserved.