ABSTRACT
Brick fences are an indispensable element of historic buildings. They are often the only remnants of the historic buildings of cities. Due to the exposure, they are displayed to extreme environmental conditions: driven rain, splash water, snow cover, ground moisture and frost. As a consequence, intensive biological and chemical corrosion develops. The purpose of the conservation and restoration works is to remove the damage caused during the operation of the fence, stop the corrosive processes and restore aesthetic values. This is connected with the application of modern materials. The decision on the selection of solutions is made on the basis of typical tests: the composition of mortars, the volume density of mortars as well as bricks. As a consequence, solutions that can intensify damage are created. One of the main causes of degradation is the subflorescence of soluble mineral salts. It involves the flow of moisture in the wall, which is disturbed as a result of the application of contemporary materials. The article presents the results of experimental and in situ research on the mechanism of moisture flow in fencing walls. Moisture maps were made for selected objects and subflorescence areas were established. Laboratory tests of historic and contemporary materials were carried out: thermal and moisture properties, microstructure parameters. The obtained results served as the output data for the simulation analysis of heat and mass transport in the WUFI 2D computer application. The simulations covered three basic variants: filling the joints, re-profiling the bricks and introducing new bricks and mortars to the wall. The result of the research is the distribution of moisture in the brick wall. A detailed analsis was made of the masonry area of the wall (range 0 to 50 mm), which is exposed to subflorescence. The obtained results clearly indicate that each of these elements has an impact on the moisture status.
