Planning is the process of thinking about the activities required to achieve a desired goal. It involves the creation and maintenance of a plan, such as psychological aspects that require conceptual skills.
Design is the creation of a plan or convention for the construction of an object, system or measurable human interaction (as in architectural blueprints, engineering drawings, business processes, circuit diagrams, and sewing patterns).
Every construction process is unique and depends on the scope and complexity of the project. But each time a sustainable house is built, the process follows typical steps, and the principles are similar for smaller scale projects like renovations. The Renovations and additions and Buying a home off the plan articles include more information on the construction process specific to those situations.