Roof Rats: The Challenges of a “Routine” Job

Doc’s Dialogue
By Austin M. Frishman, Ph.D.

Roof Rats: The Challenges of a “Routine” Job

It is no secret that once roof rats inhabit a structure, snap traps are the most effective and commonly used approach to control these pesky critters. One particular experience helped me develop some best practices while also showing me the importance of working with the customer for effective roof rat control. 

The Situation

Roof rats in an inaccessible attic area had gnawed through a pipe leading to a refrigerator below, causing water damage to the kitchen. After creating a hole in the wet ceiling, the customers noticed the rats. 

The Inspection

When I got to the site, I noted several factors before conducting an inspection. First, the adjacent large garage was packed with boxes and scattered materials, making it difficult to walk around and see the perimeter. Second, I noted the three dogs that were kept indoors, and that their food was always left out for them. Finally, I saw that pelleted rodenticides had been placed in an open dish inside the kitchen sink cabinet. 

After reviewing the surrounding area, I conducted my initial inspection. It revealed numerous rat droppings in the void above the ceiling. However, there was no rodent activity in two accessible attic areas.

I pre-baited with six expanded rat snap traps in the hard-to-reach attic area. Even though rat activity was not noted in the other two attic areas, I ensured those areas were also pre-baited. Fire ants attacked the pre-bait on the first night, but were quickly controlled with Optigard^® Flex insecticide once applied the next day. 

Two nights later, one rat was caught in a trap; no other rats were caught and signs of activity ceased for more than a week. To maintain control, tamper-resistant rodent bait stations were placed on the exterior and the dog food was only put on the floor when the dogs were being fed. Additionally, the rodenticide bait near the kitchen sink was removed because no rat activity was seen there.

Lessons Learned

This inspection helped me determine some best practices for controlling rodents. You must conduct a proper inspection and take everything into consideration because there are multiple factors that can have an impact on rodent activity. Follow up daily to monitor the bait stations and traps, and account for extra time. It may take longer than you think to complete the work and you should price it accordingly. 

Eliminating rats is only part of the solution. This experience also taught me the importance of working with the customer to achieve effective control. Let them know that they should check exterior bait stations at least once a week, look for possible openings where rats could enter, keep the garage clean and never use rodenticides inside the house to protect their pets and prevent the odor of dead rats from lingering. 

By involving the customer, using effective products and sound methods, you can achieve control of any rodent infestation.