Rats and mice cause serious damage to all kinds of structures if they are allowed access to them. damage by rodents has been documented in homes, apartments, hotels, office complexes, retail businesses, manufacturing facilities, food processing and warehouse facilities, public utility operations (especially power and electronic media operations), farm and feed storage buildings, and other structures.
in urban settings, rodents most often cause damage to older, inner-city buildings and utilities in poor repair. new housing developments may experience commensal rodent problems, but problems are more noticeable in neighborhoods 10 to 12 years of age or older. ornamental plantings, accumulation of refuse, woodpiles, and other such sources of harborage and food are more quickly invaded and occupied by rodents when adjacent to an established rodent habitat.
many types of land, air, and water transportation systems and their infrastructure also face serious rodent infestation problems. infestations are of particular concern in the transportation of foodstuffs, feed, and other agricultural products. commensal rodents consume and contaminate human and livestock feed. one rat can eat about 1/2 pound (227 g) of feed per week, and will contaminate and waste perhaps 10 times that amount.
rodents also serve as vectors or reservoirs of a variety of diseases, such as salmonellosis, leptospirosis, and murine typhus, that are transmittable to humans. additionally, they may be sources of swine dysentery, brucellosis, sarcoptic mange, and tuberculosis, all of which affect livestock or pets.
the most effective means of limiting rodent damage is rodent-proof construction. new buildings should be designed and built to prevent rodent entry. rodent-proofing is a good investment. designing and constructing a rodent-proof building is less expensive than adding rodent-proofing later. nevertheless, poor maintenance or management practices, such as leaving entry doors and unscreened windows open, will make the best constructed building susceptible to rodent entry. techniques discussed here apply both to new construction and to the modification of existing structures.
junctures where utilities (pipes, cables) enter structures require special consideration in preventing rodent entry. some earthquake design criteria require open spaces in important joints and other support areas, to allow for limited movement of tall structures. these present a real challenge in the design of rodent-proof construction.