ADU stands for "accessory dwelling unit." It occurs here in the Oregon Universal Building Code. It enables a homeowner to add a secondary building, with separate utilities, which can serve as guest accommodations, an office or studio, an income property, etc. There are certain guidelines which are being relaxed as of right now (June 2009) which will make it possible to build larger than 800 sq. feet and cover more of the lot. Revolve© has several methods of facilitating the construction of an ADU in the most ecological, economic way.