Although some modular offices may have a size-limit, they are mostly set by the amount of on-site construction you are willing to endure and whether or not you would like them to be mobile. Some aspects of construction, such as steel frames, require more on-site labor, and eliminate the option of mobility, therefore increasing the time and money needed to build your modular building. The amount of on-site labor and the features that will require it depend on your modular building’s specific needs.