Kuldīga is a town in Latvia’s western region. Through the center of the Kuldīga’s old town and interior yards there runs the little river Alekšupīte. River’s banks predominance built by stone walls in many places is degraded, as well as during the time brick vault bridges partially deteriorated and lost several significant details – brick masonry is crumbly, stone and walls plaster deteriorated, brick parapet and edges replaced by concrete. Therefore there is necessity for restoration’s works. The aim of this research was the investigation of chemical and physical properties of Alekšupīte’s bank and bridges stone materials. Scientific investigation was carried out in order to characterize authentic materials and elaborate conservation plan. The methodology used includes visual observation, granulometric analyses, classic wet chemical analyses, XRD, DTA, hydric tests and contamination with soluble salts. The data obtained indicate, that for cladding brick vault dolomitic stones and boulder, strongly hydraulic lime and dolomite lime mortars with crushed brick’s particles as hydraulic additives were used.