Abstract: A modular grid structure and method of construction for a playground, wherein the position of playground modules is easily established and rearranged within a array of securement locations and in relation to surrounding modules. The grid comprises a permanent or temporary foundation having a plurality of playground module support locations aligned in a grid or array, such that the playground may be constructed by placing the support posts of the module in connection with the foundation support locations. The disclosed support locations comprise embodiments that permanently secure the posts of a playground module using a pin-locking support hole, or alternatively a temporarily support means to movement for a shorter period while allowing swift setup and breakdown of the entire assembly, such as for temporary playgrounds.