The Impact of Wind-Driven Rain on Surface Waterproofed Brick Cavity Walls

Moisture ingress is a major cause of damage to masonry cavity walls. Products of various chemical compositions are available for wall surface treatment, aimed at reducing/eliminating water ingress. This study presents the results of full-scale wall tests designed to quantify water absorption into uninsulated and insulated brick masonry cavity walls exposed to wind-driven rain (WDR) with and without surface waterproofing. Two different waterproofing products were used: acrylic and silane–siloxane mixture. Untreated and treated walls were exposed to cycles consisting of 10 min wetting at 2.25 L/m2·min every 60 min. The results show that both treatments lead to a reduction in water ingress ranging from 90% to 97%. However, while a more consistent performance was obtained for the silane/siloxane-treated walls under repeated exposure, the results for the acrylic treatment were dominated by the original wall conditions, improved with a reapplication of the treatment. The testing protocol proposed in this study is effective in determining the performance of waterproofing treatments exposed to different levels of WDR. Both treatments prove to be effective in preventing moisture uptake in walls in moderate WDR exposure conditions, while in extreme WDR exposure conditions, the acrylic treatment is less effective.