No, not always. Only when commercial buildings exceed the exceptions in the state laws in which they are to be built are required to be stamped by a professional engineer or architect. These types of drawings, for example in the State of Oregon or the State of Washington would be any commercial building greater than 4,000 square feet in area or over 20 feet in internal height. These types of drawings are required to be stamped and prepared by a professional engineer or architect. If you require a building greater than two stories, or greater than 4,000 square feet then they shall be required to be stamped by a professional engineer or architect and additional cost will be incurred.