Roof rats are difficult to control. Their aerial habits make trapping and exclusion difficult and hazardous, and the fact that they subsist largely on fruits, nuts, and berries that they find in nature makes it difficult to deprive them of food.

If your home or business has a roof rat problem, you need to call a professional exterminator. But there are some steps you can take to reduce the chances of roof rats entering your building, such as:

• Repair or seal any obvious entry holes into the building, such as spaces around pipes or utility cables, openings in soffits, or uncapped chimneys or roof vents.
• Trim tree branches so they don't overhang or touch the building. (A horizontal space of five feet or more is recommended to discourage roof rats from leaping onto your roof.)
• Remove sources of standing water and repair any leaking spigots or exterior plumbing. (Rats require a constant source of free water.)
• Practice good housekeeping. Remove any debris that may harbor rodents.

Roof rats usually are controlled through exclusion and trapping, although baiting is sometimes used, as well. Roof rats' aerialist habits can make control very difficult, as their runways tend to be in high, often difficult-to-reach places. Pest control operators often attach traps to overhead pipes, ledges, metal beams, and other elevated runways where evidence of rat travel has been observed.

Like most other rats, roof rats are xenophobic; that is, they tend to avoid new objects in their environments. Many pest management professionals will therefore place traps along the rats' runways, but not actually set them for several days. This gives the rats a chance to get accustomed to the traps, at which time they will more readily take the bait.