Roof Rats in Durham: The Attic Climbers

Of the three rodents that invade Durham homes, the roof rat is the one that surprises people. It does not come up through the crawl space or scurry along the kitchen floor. It comes in from above. Roof rats are agile climbers that live high in the house, in attics, soffits, and the upper walls, and they thrive in Durham's warm climate and heavy tree canopy. If you are hearing scratching or scurrying overhead after dark, this guide is for you.

Why roof rats love Durham

Roof rats, sometimes called black rats, do best in warm, humid places, which is exactly the Piedmont. Two things about Durham make it ideal for them. First, the tree canopy: the mature oaks, pines, and hardwoods that shade neighborhoods like Trinity Park, Hope Valley, and Chapel Hill give roof rats a network of highways from tree to tree to roof. Second, the mild winters: there is no hard freeze to knock the population back, so roof rats stay active and keep breeding year-round. For background on the species and its habits, the EPA's guidance on managing rodents is a useful, neutral reference.

How they get into your attic

Roof rats are built to climb. They reach the roof of a Durham home by:

• Tree limbs. Any branch that touches or overhangs the roof is a direct bridge. Roof rats jump surprisingly far, so even a limb a few feet away can work.
• Utility lines and fences. Power and cable lines, and the tops of fences, become tightropes straight to the house.
• Gutters and downspouts. They climb downspouts and run the gutters to reach the roofline.
• Rough walls. Brick and textured siding give enough grip to climb.

Once at the roofline, a roof rat only needs a small gap, about the size of a quarter, to get in. The usual entry points are gaps where the soffit meets the wall, openings at the eaves and fascia, unscreened or torn gable vents, and gaps around roof penetrations like plumbing vents and cables.

Signs of roof rats

Because they live up high, the signs are up high too: scratching, scurrying, or gnawing sounds in the attic or ceiling at night, droppings in the attic (larger than mouse droppings, capsule-shaped), gnaw marks on the roofline, fascia, and wiring, and dark rub marks where they travel along beams. You may also see them running along fences, power lines, or limbs at dusk.

How to get roof rats out and keep them out

Roof rat control works from the top down, and it takes three things together:

• Remove the population. Trapping in the attic and along the roofline paths they use, with follow-up until the activity stops.
• Seal the roofline. Exclusion closes the soffit, eave, and gable-vent gaps with rodent-proof, metal-backed materials so they cannot get back in.
• Cut the highway. Trim tree limbs back from the roof, and address the fences, lines, and gutters that give them a path.

Where roof rats have nested in the attic, cleanup removes the droppings and fouled insulation and the scent trails that would draw the next ones in. Start with an inspection so the entry points and climb routes get mapped before any work begins.

Roof rat questions