For an architect-designed custom home, the design process can take three-to-six months or longer, plus an additional month for permitting. If you are having purchased plans modified and checked by an architect, the timeline is considerably shorter, but it can still take two-to-three months, including permitting. The overall time from start to finish depends on how much work needs to be done beyond what is included in the plan package. For example, if your project requires significant structural work such as adding a second story or a garage, then the building process will be extended because these items must be taken into consideration during the planning stages. Also, local building codes can affect how quickly you can get your project approved; sometimes they delay projects even after plans are complete. Finally, some projects simply take more time than others - especially when you add in elements such as selecting materials and hiring professionals to help with tasks like plumbing and electrical work.