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Signature Home Pest

Rodent exclusion

Signs of rats in a South Bay attic

Most Campbell and San Jose homeowners hear the problem before they see it. Roof rats are active at night. By the time droppings show up in the insulation, they usually have a route in at the roof or vents.

Signature Home Pest · Campbell, CA · October 2026

South Bay home exterior where roof rats often enter at the roofline

South Bay homes give roof rats plenty of cover: tile and composition roofs, mature trees, and attic vents that were never screened for a quarter-inch gap. Signature Home Pest inspects from the Campbell shop and works San Jose, Sunnyvale, Cupertino, Los Gatos, Saratoga, and Santa Clara.

What to look and listen for

  • Night noise. Scratching in the attic or walls after dusk is the most common first call.
  • Droppings and urine odor. Dark pellets in insulation, along joists, or near the hatch, plus a stale ammonia smell.
  • Chewed vents, wires, and fascia. Rats gnaw openings larger and can strip wire insulation, which is a fire concern.
  • Tunneled or stained insulation. Blown-in material shows runways. Batts get torn for nests.
  • Grease marks. Dark rub lines at pipe penetrations, roof flashing, and attic hatches.

Roof rats vs mice

The Bay Area climate favors roof rats. They climb, travel utility lines, and enter at the eaves more often than along the foundation. Mice use smaller gaps and may nest in crawl spaces as well as attics. The exclusion plan is the same idea either way: find every opening larger than about a quarter inch, repair it, then deal with animals still inside.

What not to do

Do not dump new insulation over stained material. Do not skip sealing the roof and vents. New product in an open attic gets soiled again. A rodent exclusion visit should come before a full insulation replacement.

If you are in Campbell or San Jose, call (408) 963-6024 for a free inspection. We photograph what we find and send a written plan.

Questions homeowners ask

What does rat activity in an attic sound like?

Scratching, scurrying, or light thumps in the evening and early morning. Rats are nocturnal, so daytime quiet does not mean they are gone.

Are droppings in insulation enough to call someone?

Yes. Droppings mean animals have nested or traveled through the material. We inspect, then recommend exclusion, cleanup, or both.

Need an inspection in Campbell or San Jose?

Call (408) 963-6024 or send the contact form. The visit is free. License #1148243.