BAR-CODE HOUSING SYSTEM is a computer aided design and building system for housing blocks built with industrialized processes. Architectural, building and computer-aided design systems have been conceived simultaneously as part of a comprehensive system. The architectural system is based on the aggregation of space-bars which can be combined into housing units. The addition of two kinds of bar - one containing building services and structure, the other free of both - gives rise to a multiplicity of flexible housing layouts which are generated by the computer system. Housing units in turn are assembled in linear blocks. For each block there is an indefinite number of possible facades made of freely arranged panels and openings. Facade compositions are created in an interactive way, modifying some specific design parameters (orientation, isolation, illumination, cost). The program automatically generates the documents for building a block (drawings, preliminary bills of quantities). The existing prototype consists of a generative application to create housing units, blocks and facades and an environment to visualize blocks in three-dimensions in the Internet. In the future, both applications - for generating and for visualizing - will be integrated in a comprehensive platform, which will support communication and collaboration among all agents involved in the design and construction of housing blocks: architects, manufacturers, contractors and occupants.