The importance of numerical modeling and simulation approaches increases with increased scale as it allows for early results predictions. This study evaluated the buildability of novel construction and demolition waste (CDW)-based geopolymer materials for 3-dimensional printing (3DP) structures for the built environment. The feasibility of the developed numerical model for 3DP of built environment structures was also evaluated. This study reported the fresh-state properties of geopolymer-based materials, and based on these results, numerical modeling for 3DP of geopolymer material was performed. Three cylindrical structures with diameters of 300 mm, 450 mm, and 600 mm were printed, with the same printing conditions, resulting in buildability of 352.5 mm, 322.5 mm, and 277.5 mm (total height constructed before the collapse), respectively. In the next stage of the study, a comparative analysis was performed to assess the compatibility of numerical models for CDW-based geopolymer materials. In the numerical results, three structures showed early failure prediction from experimental results at 31.91%, 29.10%, and 29.73%, respectively. The geopolymer materials developed were suitable for 3DP, and close agreement in results and repeatability were observed. The numerical model provided a reliable failure prediction for different structures. Hence, the model can be utilized to evaluate the buildability of the structures before the actual 3DP, which can significantly reduce the time and cost of the project.