Roof rats are excellent climbers and typically nest in elevated areas such as attics, ceilings, and upper levels of buildings. They often access structures by traveling along tree branches, fences, or utility lines. 

Homeowners commonly notice scratching or movement in ceilings at night, droppings in attic spaces, or signs of gnawing in elevated areas. Because they are nocturnal, activity is often heard before it is seen. Roof rats can damage insulation, wiring, and stored items in attics. Like other rodents, they contaminate surfaces and can spread bacteria as they move through a structure. 

Because they nest above living spaces, infestations can go undetected for longer periods, allowing populations to grow. Once established, they tend to return to the same nesting areas unless access points are sealed. Without intervention, roof rat activity can spread throughout the structure, leading to ongoing damage and repeated infestations.