How Do I Get Rats Out of an Attic?

Attic activity in New Hampshire is commonly roof rats, which favor elevated nesting over the ground-level burrows Norway rats prefer, and typically enter via overhanging tree branches, power lines, or gaps along the roofline. Look for droppings, gnaw marks on rafters or wiring, and greasy rub marks near likely entry points before deciding on a plan.

Pre-bait unset snap traps along attic runways and rafters for a few days, then set them. This is also the step where the most important warning applies: the University of Nebraska Extension states plainly not to close an opening until the species has been identified and a control program decided on. Seal too early and any rat still inside dies in a void you can't reach, causing weeks of odor, fly and maggot activity, and a cleanup problem far worse than the original one.

Watch for roughly a week with no new droppings and no disturbance to any monitoring materials (like a loosely placed newspaper plug at a suspected opening) before treating the attic as empty. Only then move to permanent exclusion.

Trim overhanging branches that give roof rats a bridge to the roofline, screen attic and gable vents, and seal roofline and utility penetrations larger than ¼ inch with metal flashing and hardware cloth — materials rats can't chew through, unlike caulk or foam alone. Finish by cleaning droppings and nesting material with the CDC wet-clean method: air the space out, spray with disinfectant, and never sweep or vacuum dry droppings, which aerosolizes contaminants.