Although designing a structure is an iterative process by nature, a very limited number of iterations can be done with the traditional methods to reach the near-optimal solution. However, with the development of information technologies, the usage of parametric design in the construction industry has expanded. This paper aims to show the potential benefits of implementing parametric design and optimization techniques in the early structural design process. For this purpose, a simple parametric model of a steel frame with a truss roof system was created and then optimized for minimum mass and a given floor area. The case study demonstrated that the application of parametric design can reduce the Global Warming Potential of the structure by 7.6 % by optimizing the geometry and the cross-sections, leading to a more sustainable solution.