Long term performance of chemical damp-proof courses: twelve years of laboratory testing

This paper presents the results of a long-term laboratory experiment aiming to investigate the performance of different chemical treatments for rising damp in masonry walls. The investigation began in 1989/1990, when 20 test walls of different thickness and material were built inside a laboratory. Each wall was built inside a tank that was filled with water and sealed with a polyethylene sheet. The tanks were refilled every two weeks, and the values of the refills were measured during these years. In 1992, ten of the walls were treated with six different chemical damp-proof course treatments. The analysis of the time series of the monthly water refills allowed comparison of the performance of different products, showing that silane-based treatments were the most effective. The amount of absorbed water was nearly halved when silane-based products were used, with an even better performance observed when the lying of the blocks was changed.