Abstract: A modular building is constructed at a module construction area using pre-made component parts that are produced at a component production area. The pre-made component parts are measured, cut and drilled at the component production area and supplied to a module maker at the module construction area so that the module maker assembles the modules without measuring, cutting or drilling the component parts. The module maker uses a plurality of jigs to assemble the modules. The jigs remain attached to the modules during transport to a building site and are removed from the modules prior to the modules being positioned on the foundation.