© 2007 Francis Loetterle. All Rights Reserved. A rational building system of relatively few standardized components and dimensions is the logical result of modular design and the key to prefabricating and mass-producing affordable houses and schools. Rational selection and integration of building systems, components and materials should be based upon design objectives and design context. There are, however, general selection criteria common to all system, component and materials decisions: availability, function, durability, efficiency, sustainability, economy, modularity, open architecture, lightness and compatibility. The following is a list of relatively small-scale residential building systems, components and materials, which derives from these selection criteria. These are building systems well suited to mass producing houses in California, and they are, for the most part, the ones used in the projects illustrated in the second part of this book. The list is organized according to building systems categories put forward in the American Institute of Architects, "Building Systems Integration Handbook," Structural, Exterior, Interior, Mechanical and Electrical. These building system, assembly and component selections stem from using light gauge steel framing instead of wood framing which was based upon the following advantages: Use of light gauge steel framing obviates the need to sacrifice trees for residential construction. One third to one half of the steel in galvanized light gauge steel framing is recycled. Light gauge steel framing members are manufactured in exactly the quantities, shapes, gauges, and lengths required resulting in less waste material than wood. Light gauge steel framing can be shaped, cut and joined with greater speed, precision, and consistency in a factory mass production setting than wood. Light gauge steel framing does not warp, bow, shrink, check, rot or succumb to termites like wood. Light gauge steel framing weighs approximately 30% less than wood, item for item. Every piece and assembly is easier to handle and carry. Since seismic force resistance required of the building structure is in proportion to the mass of the building, a lighter structure means less seismic force to resist. The cost of light gauge steel framing is stable and predictable and the cost of wood framing is not. Light gauge steel framing is not combustible, and walls, floors and ceilings framed in steel qualify for higher fire resistance ratings and lower insurance premiums than their counterparts framed in wood. Screws in light gauge steel framing provide higher resistance to withdrawal than nails in wood framing. However, light gauge steel framing is a much better conductor of heat than wood framing. Until recently it was thought that houses framed in light gauge steel were unavoidably inferior to houses framed in wood with regard to resisting heat transfer across the thermal boundary. But light gauge steel framing becomes equal or superior to wood framing with regard to conducting heat when extruded polystyrene (EPS) stud and joist flange caps are inserted as a thermal break between the exterior finish and the steel framing. When light gauge steel framed houses use EPS flange caps, a minimum overall amount of framing material and all of the other energy saving procedures available to wood framed houses, their energy saving performance is phenomenal. Excerpted from "Rational Building Systems" an essay in Mass Housing Design Principles and Prototypes. Mass Housing Design Principles And Prototypes, by Francis Loetterle, 118 pages, 55 drawings, $45.00. Click here to order This book addresses the design of efficient and sustainable mass housing. The principles and prototypes presented are the products of twenty-eight years research and practice. The design principles address: Efficiency and Sustainability, Open Architecture and Modular Design, Rational Building Systems, Cost and Affordability, and Speed. The prototypes are comprised of unbuilt projects and hypothetical exercises. Modular planning prototypes for mass housing are presented in addition to single and multifamily modular design prototypes. All of the mass housing prototypes employ light gauge steel construction, modular design, prefabrication and mass-production. Each prototype addresses an obvious and pressing housing problem that has not received much current recognition or tangible solution. Some examples of pressing problems addressed are urban infill and small scale redevelopment housing, low income senior citizen housing, working poor housing, especially in developing countries, war refugee and war recovery housing and disaster relief-recovery housing. The contents of this book should be of interest to all people, worldwide, involved in mass housing; primarily planners, architects, engineers, students and teachers, but also housing and urban development agencies, disaster relief agencies, international development banks, redevelopment agencies, zoning code agencies, low cost housing mortgage lenders, production homebuilders and residential construction component manufacturers. Efficient and sustainable mass housing is a worldwide problem both critical and current. These mass housing principles and prototypes are presented in conjunction with the equally pressing and much larger problem of efficient and sustainable new neighborhoods, communities, towns and cities. The book is not a critique of what is but a series of suggestions concerning what to do instead. Back To Top Built By WebSight design Francis Loetterle, Architect, modular, design, affordable, low cost, mass, housing, schools, classrooms, land use, infrastructure, master, planning, efficient, sustainable, communities, fast-track, delivery, building, systems, components, light gauge, residential, inline, steel framing, pre-engineered, prefabricated, production, project, management, design-build, manufactured, HUD Code, panelized, disaster, recovery, redevelopment, single, multi, family, homes, urban, infill">