Layout planning is a process of sizing and placing rooms (e.g. in a house) while attempting to optimize various criteria. Often there are conflicting criteria such as construction cost, minimizing the distance between related activities, and meeting the area requirements for these activities. This paper describes new techniques for automating the layout planning process using evolutionary computation. New innovations include allowing polygonal exteriors and multiple floors. Multiobjective ranking algorithms are tested to balance the many objectives in this problem. The evolutionary representation and requirements specification used provide great flexibility in problem scope and depth of problems to be considered. A variety of pleasing plans have been evolved with the approach.