Part I: The rehabilitation of affordable housing faces many institutional and regulatory barriers. Because the existing stock varies so much in condition, age, and construction methods, the rehab process is far less predictable and in many ways more challenging than new construction. Nevertheless, the rehabilitation of the country's aging stock is a major resource for meeting the Nation's affordable housing needs. Despite the demonstrated benefits of rehabilitation, there is potential for even greater use for the existing stock, not only to address affordable housing needs, but to promote broader community revitalization goals as well. However, to date there has been a lack of in-depth practical guidance on the many regulatory and other factors that act as barriers to rehabilitation of housing that is affordable. Gaining a sound grounding of these issues has been difficult because barriers vary from project to project and from community to community. To address these concerns, HUD,as part of its American 's Affordable Communities Initiative, entered into a cooperative agreement with the National Trust for Historic Preservation to identify and document workable solutions to the major barriers to urban rehabilitation. The product of this collaboration is this report, Best Practices for Effecting the Rehabilitation of Afordable Housing, which is intended to fill this information gap and, in so doing, empower decision-makers and housing professionalsto begin work to eliminate these barriers. This two-volume report distills the practices that have been shown to work in many settings to implement the renovation of affordable housing. These best practices are designed to address the challenges to rehab at its development, construction, and occupancy stages. Volume I is a comprehensive resource guide to state, local, and federal tools for overcoming barriers. <a href="http://www.huduser.org/publications/pdf/BarriersVol1_part2.pdf">... II</a> provides analyses of key rehab resources and barriers, and case studies of state and local efforts to overcome major regulatory impediments.