Destruction caused by excessive moisture is a common problem in heritage buildings made of brick. Historic buildings usually have walls that of different constructions, i.e. walls with all joints filled, walls without filled vertical joints, and walls with a layered arrangement. Excessive moisture causes brick cavities, reduces the load-bearing capacity of walls, is unsightly, and can lead to the destruction of walls or the failure of a building. Secondary anti-damp insulation is used to protect the brick walls of historic buildings. However, there has not been enough research to confirm the effectiveness of secondary anti-damp insulation. This type of insulation is performed with the use of the injection method, with various factors (such as soils, the type of injection material, etc.) that affect the effectiveness of the insulation being taken into account. There is also insufficient research on how injection material penetrates brick. This article presents the current state of knowledge, research gaps, and research regarding anti-damp insulation in historic buildings made of brick, and also the perspectives of future research. The authors propose the use of non-destructive and destructive methods to assess the effectiveness of anti-damp insulation in brick walls.