This handbook contains construction details representative of good practices for the design and installation of energy efficient basement, crawl space, and slab-on-grade foundations. This handbook is a product of the U.S. Department of Energy Building Envelope Systems and Materials (BTESM) Research Program centered at the Oak Ridge National Laboratory. The major objective of this research is to work with builders, contractors, and building owners to facilitate the reality of cost-effective energy efficient walls, roofs, and foundations on every building. This handbook is one of a dozen tools produced from the BTESM Program aimed at relevant design information in a usable form during the decision-making process. The construction details are accompanied by critical design information useful for specifying structural integrity; thermal and vapor controls; subsurface drainage; waterproofing; and mold, mildew, odor, decay, termite, and radon control strategies. Another useful feature is a checklist which summarizes the major design considerations for each foundation type "Y basement (Chapter 2), crawl space (Chapter 3), and slab (Chapter 4). These checklists have been found to be very useful during the design stage and could be very useful during construction inspection. Foundation insulation is gaining acceptance in the U.S. residential building industry. Moisture and indoor air quality problems caused by faulty foundation design and construction continue to grow in importance. The material contained in this handbook represents suggestions from a diverse group of knowledgeable foundation experts and will help guide the builder to foundation systems that are easily constructed and that have worked for others in the past, and will work for you in the future.