Transcriber Notes Text emphasis is denoted as =Bold= and _Italics_. U. S. DEPARTMENT OF AGRICULTURE FARMERS' BULLETIN No. 1638 RAT PROOFING BUILDINGS and PREMISES [Illustration] FOOD AND SHELTER are as essential to rats as to other animals, and the removal of these offers a practical means of permanent rat control. The number of rats on premises and the extent of their destructiveness are usually in direct proportion to the available food supply and to the shelter afforded. Rat proofing in the broadest sense embraces not only the exclusion of rats from buildings of all types but also the elimination of their hiding and nesting places and cutting off their food supply. Through open doors and in other ways, rats may frequently gain access to structures that are otherwise rat proof, but they can not persist there unless they find safe retreats and food. When rat proofing becomes the regular practice the rat problem will have been largely solved. Washington, D. C. Issued December, 1930 RAT PROOFING BUILDINGS AND PREMISES By James Silver, _Associate Biologist_, and W. E. Crouch, _Senior Biologist, Division of Predatory-Animal and Rodent Control, Bureau of Biological Survey_, and M. C. Betts, _Senior Architect, Division of Agricultural Engineering, Bureau of Public Roads_. CONTENTS Page Introduction 1 General principles of rat proofing 2 Rat-proofing farm buildings 2 Barns 5 Corncribs 7 Granaries 9 Poultry houses 9 Other farm structures 11 Rat proofing city buildings 13 Markets 18 Warehouses 19 Rat proofing the city 20 Model rat-proofing ordinances 21 INTRODUCTION THE PRINCIPLES of modern construction of buildings are opposed to everything conducive to the best interests of the rat. They call for the liberal use of indestructible and noncombustible materials, as well-made concrete and steel, and these are too much for even the sharpest of rodent incisors. They include, also, fire stopping in double walls and floors and the elimination of all dead spaces and dark corners, and the rat is left no place in which to hide. They embody sanitary features that provide for hygienic storage of food, and the rat can not live without something to eat.