This paper investigates the effects of construction errors during the implementation of reinforced concrete T-beams. These errors are classified into two main sections. The first focuses on the position and ratio of reinforcing bars, while the other is related to the concrete strength. A total of ten specimens of T-beams were tested to assess the effect of the possible defects in the construction sites, viz. impact of misplacement of slab reinforcement, irregular arrangement of slab reinforcement, the change in bar diameter of slab reinforcement and the effect of casting method of concrete on the structural behavior of T-beam sections. The results indicated that the faulty placement of slab reinforcement leads to a lower bending moment capacity of the slab (brittle behavior) and the steel strain of slab decreases as the height of slab reinforcement decreases. The irregularity of the reinforcing bars in concrete slab affects the ultimate load carrying capacity of the slab. Also, it was found out that well-arranged distribution of reinforcement improves the ductile behavior of the slab and reduces the corresponding deflections.