Blueprint Copyright Law
All house plans “home blueprints” are protected under the United States copyright law. No house plan may be copied or redistributed without the permission of the architect or home designer.
Similar to purchasing a license for software to use on your computer, when purchasing a residential home blueprint, you are purchasing one license from the designer to build that home. Once that home is built, it is illegal to build the same house from that plan. Additional copies may be obtained from the origin of purchase. They are called reproducables.
With the purchase of reproducibles, a copyright release or license is also provided with the sale. The purchaser is generally allowed to make up to a maximum of 12 copies for the construction of a single dwelling only. For any extended use, and to avoid any copyright/license infringement, an additional release must be obtained from the original designer.
Having modifications done to any specific building plan does not release copyright from that plan. Modifications performed on any house plan become copyrighted material by the house planner.
Violation of blueprint copyright law may be very severe. The responsible parties are required to pay the designer's actual damages (which may be substantial) plus any profits made. The copyright law also allows the designer to recover statutory damages which can be as high as $100,000. Finally, the infringe can be required to pay the designer's reasonable attorney fees which often exceed the damages.