Rooftop rats: how they get up there and the one entry point everyone misses

The five access routes

1. Tree canopy contact: any branch within 1 m of the roof line provides direct roof access. Roof rats are exceptional climbers — they can jump 1.5 m horizontally from a branch and land on a slope. In North Vancouver, West Vancouver, and Vancouver's west-side, mature Douglas fir, cedar, big-leaf maple, and ornamental cherry provide the primary access corridors.
2. Hydro lines: roof rats run along utility lines from the street pole to the home entry point — typically where the service drop attaches to the house near the roof. This gives access to the roof structure directly at the attachment point, which is often poorly sealed. Hydro line access is common in Kitsilano, Commercial Drive, and Mount Pleasant where infill density means lines run close to adjacent rooflines.
3. Adjacent fences and trellises: a 1.8 m wooden fence gives roof rats vertical access to a wall or roof line, especially if vegetation covers the fence. Ivy, climbing roses, and wisteria on fence-to-wall trellises are essentially ladders. This is the 'entry point everyone misses' — homeowners assume the tree canopy is the issue and ignore the fence.
4. Roof returns and soffit-fascia gaps: once on the roof or upper wall, roof rats enter through the gap where the soffit meets the fascia (the soffit-fascia junction). This gap is standard on most pre-2000 Metro Vancouver homes — the stock construction leaves a 10-20 mm gap that isn't immediately visible from the ground but is obvious from a ladder.
5. Gable vents and dormer junctions: gable vents with stock louvre gaps (typically 8-12 mm) are large enough for roof rats. Dormer junctions on older heritage homes often have inadequate flashing that creates persistent gaps.

Once inside the soffit: how they navigate the structure

Once inside the soffit or through a gable vent, roof rats move into the attic along the top-plate of the exterior wall. From there, they access the full attic floor, ceiling joists, and any internal partitions that have wall cavities running through the roof structure. The characteristic sound of a roof rat infestation is overhead running — specifically the patterned sound of a rat running along the same joist route repeatedly. This creates the runway smudge marks that techs look for on inspection.

Roof rats almost never descend below the ceiling level except in rare cases where food is available in a kitchen directly below an accessible wall cavity. Their activity is concentrated in the upper third of the home — attic, ceiling, and upper wall cavities. This is why a Norway rat protocol (exterior perimeter bait stations, basement-level snap traps) completely misses roof rat populations.

The North Shore canopy problem

North Vancouver and West Vancouver have one of the highest roof rat densities in Metro Vancouver, driven by mature Douglas fir and western red cedar providing continuous elevated cover between properties. A single mature fir at a property corner can give roof rats access to three adjacent rooflines. The fir itself may be on Crown or District land, not the homeowner's property — which means the homeowner cannot trim it unilaterally. In these cases, exclusion at the roof line (sealed soffit, hardware-cloth gable vents) becomes the primary tool because the canopy access point cannot be eliminated.

The inspection sequence for suspected roof rat access