Now a days, construction industry is one of the most over loaded industry and is responsible for carbon emission, the process of enhancing the life of existing structures reduces the impact on the environment. In this regards, external strengthening of concrete structures is necessary under repair and rehabilitation of structures. This will increase the load carrying capacity and life span of concrete structures. In past decade fiber reinforced polymer (FRP) has been widely used as externally strengthening material due to its high strength and light weight. However, ferrocement is one of the suitable alternatives over costly FRP strengthening technique. Ferrocement is thin composite material having better crack resistance ability, ductility, good impact resistance and can be easily wrapped over beam surfaces. Very less research work is available on torsional behavior of concrete beam strengthened by ferrocement due to its complex loading. As practically beam and slab are cast monolithically, strengthening of beam in U- shape is more practical than strengthening all sides. This paper represents an experimental study conducted on reinforced concrete beam strengthened externally by U- shaped ferrocement with different strengths of mortar. This paper also addresses the torsional capacity and angle of twist of reinforced concrete beams. The experimental study was conducted on total 10 number of reinforced concrete (RC) beams of 150 mm × 200 mm × 1500 mm in size. The main purpose of study was to check the effect of different strength of mortar on ferrocement strengthening system under torsion keeping layer of wire mesh and thickness constant. Different strength of mortar mix, fabricated by varying water/cement ratio of 0.400–0.475 at stepped increment of 0.025. Result shows very less improvement in ultimate torsional strength and average 10.33% increment in angle of twist over normal beams.