Architecture, Building and Structure Design 2 Oaks House single family house by Obia Ltd. Architecture Studio From the architects: The house is located in a low-rise residential area near Sofia, in the outskirts of Mountain Vitosha. The project was preliminary defined as a contemporary house with rational spaces, very high energy efficiency and indoor climate comfort, fully controlled by a building automation system. Main challenge of the design was the preservation of the two existing old oaks and their integration in the spaces of the house. The trees create a natural micro-climate and function as a living element in the composition.