Performance analysis of gravity chemical blockers in the treatment of rising damp in masonry walls

The objective of this work is the performance analysis of the rising damp treatment in walls, through the use of chemical blockers (i.e., crystallizing and water repellant) available in the Brazilian market, with their introduction by gravity. As there are no standardized tests for such a study, experiments conducted by other researchers were used as a reference. The evaluation of the rising damp was achieved by the calculation of the water absorption rate in the specimens, allied with the images obtained by the thermographic camera. From the results, it was concluded that the treatment did not completely reduce the pathological manifestation in the walls, but both products performed well and managed to reduce the water absorption rate considerably.

The effect of rising damp on heat transfer performance and energy consumption of two kinds of Chinese blue-brick masonry walls

Rising damp is common in brick buildings due to groundwater and natural precipitation, which not only causes deterioration of the walls, but also significantly affects the heat transfer coefficient, thermal inertia, and building energy consumption. In order to clarify the effects of rising damp on the heat transfer through traditional Chinese brick solid wall and cavity walls, two types of wall of 1.2 m wide and 3 m high were built in the laboratory. The heat transfer performance under the influence of capillary rising was tested by Simple heating box – heat flow meter method. Based on the data obtained from the experiment, the Energyplus was used to simulate the energy consumption of a Chinese typical residential building influenced by rising damp. The results proposed 3.67 W/m2·K and 3.61 W/m2·K as the recommended heat transfer coefficient for the moisture affected parts in the experimental solid and cavity wall, and the rising capillary water increased the heat transfer coefficients by 74% and 84%, respectively. The heating and cooling load of the solid-wall building under the influence of capillary water increased by 18.5% and 29.6%, respectively, while of cavity-walls building increased by 6.5% and 11.8%.

Capillary rising damp in Venetian context: state of the art and numerical simulation

The fragility of Venice and its buildings are linked to the floods, observed since ancient times and emphasized in recent years: the periodic sea level rise, accompanied by rising damp, are the main causes of the alteration. In particular, the rising damp causes a series of complex diseases in the historic buildings, such as physical decay, chemical or biological, with loss of aesthetic and economic value. In addition, greater heat dispersion and reduced thermal comfort can also occur in interior spaces, with consequent risks for human health. This is a sign of “Sick Building Syndrome”. It is very important to develop models for assessing the vulnerability of assets and to manage sustainable plans related to maintenance processes and activities, satisfying the requirements of effectiveness and compatibility. Basing on numerical models performed with the WUFI 2D software, the paper analyses the different behavior of rising damp in relation to materials or masonry structures. In particular, the construction techniques and typical materials used in Venetian buildings were investigated, such as clay brick walls, lime plaster, Marmorino and Cocciopesto, adopted mainly to limit the capillary rise also caused by the phenomenon of “acqua alta”.