Treatment of rising damp in historic buildings: Experimental campaign of wall base ventilation and interface effect analysis

Abstract

The treatment of rising damp in historical building walls is a very complex procedure. In this work it is presented an extension of the continuous "in situ" results of the rising damp treatment conducted in a Portuguese historical church, using the wall base ventilation technology. The results, registered over four years, clearly reveal the best ventilations periods and indicate that the best solutions must correspond to admit outside air during summer periods and inside air during winter periods. Furthermore, another important aspect was to better understand the difference in absorption behaviour between walls with and without joints when the rising damp treatment is conducted. It also presented an experimental campaign and a critical analysis of water absorption in samples of clay brick with and without joints and joints with different contact configurations (perfect contact, hydraulic continuity and air space between layers). The results showed that when the moisture reaches the interface,the wetting process gets slower due to the interfaces hygric resistance. This resistance was more pronounced for joints with air space between layers and less for joints with hydraulic continuity.