Solving the one-dimensional cutting stock problem (1-D CSP) has been widely integrated in construction industry for better managing cutting reinforcement steel bars (rebars). To provide the required tensile strength to the structure, the structural designer determines the diameter sizes of rebars, which can be adjusted as long as the rebar to concrete area ratio remains constant. The decision-maker has the option to alter the diameter size to optimize cutting patterns, thereby reducing raw material usage. In our study, we address the cutting stock problem by considering not only the cutting patterns but also the diameter sizes, with the objective of minimizing raw material usage. Unlike the classical cutting stock problem, where the number of pieces to be cut is known in advance, in this case, the number of pieces is not known until the diameter sizes are selected. To tackle this challenge, we propose a solution that employs a pseudo-polynomial formulation. Our computational study shows that converting diameters could enhance the 1-D cutting stock problem's solution quality by up to 6%.