© 2022 the Author(s).Although external jacketing with fiber reinforced polymer (FRP) sheets is one of the fastest strengthening methods for Reinforced Concrete (RC) structural members, the process of plaster removal extends the operation time, which must be done before jacketing with FRPs due to its potential to reduce efficiency of jacketing application according to ACI 440.2R-17. However, since the jacketing application is not a bond critical application, plaster removal can be eliminated, which is an effective strategy in terms of labor and operation cost. Therefore, a preliminary experimental study is conducted to examine the effectiveness of external FRP jacketing of RC columns without removal of plaster on their surfaces. As low strength concrete is one of the typical features of the substandard RC structures in developing countries such as Turkey, eight RC short columns are produced with low strength concrete (C15) and then plastered with different thicknesses (0, 10 and 40 mm). The nominal compressive strength of the plaster is 2.5 MPa at 28 days. The test results show that external FRP jacketing applied to the column with the plaster is effective and that the ultimate load and axial strain are satisfactory. Furthermore, the thickness of the plaster between the concrete member and FRP layers has an important role on the efficiency of the external jacketing.