Rodent Exclusion Results — Before & After Gallery Granite Bay
Every exclusion job produces a documented change to the structure. The following gallery shows typical before and after conditions for the most common entry point types we address in Granite Bay and Placer County. What looks like a small gap to the eye is a significant access opportunity for a roof rat or Norway rat.
Why Documentation Matters
Rodent entry points are easy to miss without knowing what you are looking for. Most homeowners who call us have not found the entry point themselves, even in cases where it is relatively obvious in photographs. Part of what we provide is documentation: photographs of what was found and photographs of what was done to address it. This serves two purposes. First, it gives the homeowner a permanent record of the work. Second, it allows future inspection to compare current conditions to the sealed state at the time of work.
The gallery below shows representative examples from our Granite Bay and Placer County work. Each entry type represents a category that appears with high frequency in our inspection history. The conditions described are typical, not exceptional, and the gap sizes shown are within the normal range for structures that have had active rodent entry.
Common Entry Points: What We Find and How We Seal Them
Before: A standard roof soffit vent with the original factory screen either corroded through, missing, or never installed. The vent opening is typically 4 inches by 16 inches or 4 inches by 8 inches. No mesh in place. Roof rat droppings visible inside vent cavity where the animals enter at night and exit before dawn. Often the only visible indicator is a dark greasy rub mark on the vent frame edge from repeated travel.
After: New 1/4-inch galvanized hardware cloth cut to size and secured to the vent frame with sheet metal screws through pre-drilled holes. Galvanized mesh rather than plastic screen, which roof rats can chew through in one night. The mesh extends past the vent frame edges by at least 1/2 inch on all sides and is secured at 2-inch intervals. Sealed condition: no gap larger than 1/4 inch across the vent face.
Before: A gap at the point where the roof deck meets the top of the fascia board. Typically 1/2 inch to 1.5 inches wide, running 12 to 24 inches along the fascia. Created by fascia board shrinkage, rafter tail splitting, or original construction gap that was never sealed. Often visible only from above the roofline when inspecting the perimeter from a ladder. Fresh gnaw marks on the raw wood edges of the gap from entry attempts that widened the original opening.
After: Sheet metal flashing cut to cover the gap area, with a folded edge at the top that slides under the first course of roof material and a lower edge bonded to the fascia face with exterior-grade construction adhesive and stainless steel screws. The flashing extends past the gap by at least 3 inches on each side. Metal rather than wood fill because rodents will gnaw back through wood infill over time. Galvanized finish for corrosion resistance in the roof zone.
Before: A round or oval gap where electrical conduit, communications cable, or plumbing vent enters the structure at the upper wall or roof level. Typically 3/4 inch to 2 inches of open gap around the utility, either never sealed originally or with original foam fill deteriorated. Insulation material pulled away from the penetration inside the attic, indicating rodent nesting activity around the heat of the pipe or cable. Roof rat entry via utility conduit is particularly common in older homes where original sealant has failed.
After: Gap cleared of deteriorated material. Copper mesh packed tightly around the utility at the penetration point, then filled with expanding foam over the mesh. The foam over copper mesh produces a permanent, chew-resistant seal: the foam without mesh can be chewed through, but copper mesh embedded in the foam matrix resists repeated rodent gnawing. The penetration exterior is finished flush with the wall surface and painted to match where visible from the roofline.
Before: A foundation vent opening with the original stamped-metal cover corroded, bent away, or missing entirely. Opening typically 8 inches by 16 inches. Norway rat entry via open foundation vents is the most common ground-level entry pathway we document in Placer County. Crawl space inspection confirms Norway rat activity: droppings along the foundation beam, vapor barrier displaced, and burrowing evident in soil adjacent to the foundation.
After: Heavy-gauge galvanized louvered foundation vent cover installed with structural screws into the foundation frame. Heavy-gauge rather than standard residential-grade covers because standard covers deform under persistent rodent gnawing pressure. Frame sealed to the foundation masonry with exterior-grade caulk on all four sides. Where the existing vent opening is irregular or damaged, the opening is first squared with a metal frame before the cover is installed.
Before: The plumbing vent stack exits through the roof with a rubber boot seal that has cracked, deteriorated, or separated from the stack pipe, creating a gap of 1/4 inch to 3/4 inch between the boot and the pipe. This gap is at the roof level, typically at or above the ridgeline on single-story homes, making it invisible from ground level. Roof rats that have roofline access from tree canopy find plumbing stack gaps by investigating every protrusion from the roof surface.
After: Deteriorated rubber boot removed and replaced with a new EPDM roof boot of the correct diameter for the stack pipe. Where the stack pipe itself has a gap below the boot, copper mesh is packed into the gap before the boot is installed. The replacement boot is sealed to the roof sheathing with roofing mastic on all sides. Where existing shingles have been lifted or damaged by the failing original boot, the surrounding shingle course is re-bedded and sealed.
Before: A garage door bottom seal that has deteriorated, contracted, or was never installed correctly, leaving a gap of 1/2 inch to 1 inch along part or all of the bottom of the door. Norway rats enter through garage door gaps by flattening and squeezing through sections where the seal is elevated by uneven concrete, warped door panels, or seal material gaps. Evidence: droppings in the garage corners, gnaw marks on stored items, and Norway rat-sized runs along the base of the garage walls.
After: Garage door bottom seal replaced with a heavy-gauge reinforced rubber seal with an interior metal attachment channel, installed on the door bottom rail. Where the concrete floor is uneven, we first assess whether the unevenness is causing the seal contact issue and recommend floor leveling if the gap is structural. The replacement seal is selected to maintain a positive contact with the floor surface across the full door width without excessive drag that would affect door operation.
What Professional-Grade Materials Mean
Not all exclusion materials are equal. The difference between materials that hold for one season and materials that hold for a decade is significant in Placer County, where annual fall entry pressure tests every sealed opening every year.
1/4-inch galvanized welded wire mesh is the standard for vent openings and areas exposed to direct rodent contact. Gauge matters: lightweight galvanized mesh can be deformed by persistent gnawing. We use a minimum 19-gauge mesh for all exposed rodent-contact applications.
Used at utility penetrations and irregular gap fills because copper does not compress or shift the way steel mesh can when expanding foam is applied over it. Copper mesh provides the rodent-deterrent substrate that makes foam-over-mesh fills permanently chew-resistant.
Galvanized steel flashing at roof-to-fascia gaps and similar structural transitions. Sheet metal provides a rigid, non-chewable closure that remains effective even under sustained gnawing pressure. Thickness is selected for the specific application based on the size of the area being closed.
Sealant selection for exterior rodent exclusion requires UV resistance, flexibility over a temperature range from Placer County winters to summer roof deck temperatures, and adhesion to multiple substrates. Consumer-grade silicone products applied over raw wood or masonry without primer fail within 1-2 seasons.
There is no gap or entry type on this page that does not have a correct professional closure method. The entry points that have sustained rodent problems for years in Placer County homes are not difficult problems. They are unmapped or incorrectly addressed problems.
Related Resources
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Every property inspection produces a complete photograph record of entry points found and work completed. See what is actually getting in before you decide how to address it.