Extensive research efforts have been made in construction simulation. Nevertheless, work space is neglected or not explicitly represented, and spatial conflicts are not considered in simulation tools. Accordingly, finding possible solutions to spatial conflicts is not integrated within the simulation. Spatial conflicts should be considered and properly resolved because they affect construction performance in terms of safety and productivity, especially when spatial constraints are crucial to the project. A conflict-free simulation provides a better means for the practitioners to check the simulation results and compare various solutions. In addition, explicit representation of space is required to support planners with the evaluation of spatial organization of more efficient and safer workspaces on construction sites. The objective of this research is to propose a cell-based simulation method considering spatial constraints for the decision-makers to perform efficient spatial evaluation of site layouts, to identify and resolve spatial conflicts during construction operations, and then to facilitate the optimization of the site layout and construction resources from a variety of requirement perspectives that planners would normally consider in a real project. This method consists of the pre-processing, main-processing and post-processing phases, integrating site layout planning, simulation and animation of the simulation results. In this method, the spatial constraints, site layout patterns and resource allocations can be explicitly represented by cells. Consequently, spatial conflicts can be detected and resolved.