Trapping eliminates individual rodents — exclusion eliminates the infestation permanently. Every mouse removed by snap trap is replaced within 2–3 weeks by the next rodent from outside. Sealing every entry point (holes ¼ inch or larger for mice; ½ inch for rats) with the right materials stops the infestation at its source. Exclusion is the only permanent solution; trapping is temporary management.
Best Rodent Exclusion Products — Ranked
Xcluder is used by USDA, CDC-certified rodent-exclusion programs, and most professional PCOs as the gold standard for gap sealing. The product is a blend of coarse stainless steel wool fibers and polyester fill that rodents cannot chew through — the stainless steel fibers fray and irritate the rodent's mouth and teeth on contact, and the combination of steel and polyester cannot be pulled apart like plain steel wool. Steel wool alone (without synthetic fiber) compresses and can be pushed out of a gap; Xcluder maintains its form.
How to use: Cut Xcluder to the approximate shape of the gap. Stuff it tightly into the gap using a screwdriver or putty knife — pack it firmly so it fills the full depth of the gap. Then seal over the surface with caulk, foam, or hydraulic cement depending on the surface type. The Xcluder provides the rodent-proof barrier; the sealant prevents it from being displaced.
Where to use: Around all utility penetrations (plumbing pipes, electrical conduit, gas lines through foundation or walls), foundation cracks, gaps around the base of exterior doors, gaps in the garage door frame, and the gap between the sill plate and foundation where these surfaces are not flush.
Hardware cloth with ½-inch openings and 19-gauge (minimum) wire is the appropriate material for covering larger openings — gable vents, foundation vents, soffits, and gaps at the roofline. Unlike window screen (which rats and squirrels chew through in seconds), 19-gauge galvanized hardware cloth requires gnawing pressure that rodents do not sustain when they encounter resistance. Cut to size with tin snips and attach with galvanized screws (not staples — staples pull out).
Note on gauge: For squirrels and raccoons, use 14-gauge hardware cloth minimum — squirrels can deform and eventually work through lighter gauge over time. For mice and rats, 19-gauge is sufficient.
After filling a gap with Xcluder or hardware cloth, the surface must be sealed to prevent the fill material from being displaced and to close any remaining micro-gaps. DAP Dynaflex 230 is an elastomeric sealant that remains flexible when cured — it expands and contracts with temperature changes without cracking, unlike rigid caulks. This flexibility is critical for exterior applications where temperature swings cause expansion and contraction of building materials.
For gaps larger than ½ inch: Use expandable foam (Great Stuff Pest Block, which contains capsaicin — a deterrent to gnawing) over Xcluder fill. For gaps up to ½ inch at the surface: Dynaflex 230 caulk directly. For foundation cracks: hydraulic cement for water-exposed areas, then caulk over when dry.
Standard expanding foam (Great Stuff, Loctite Tite Foam) is NOT rodent-proof — mice and rats chew through it easily. Great Stuff Pest Block adds capsaicin (hot pepper extract) to the foam formulation as a deterrent to gnawing. It is significantly more effective than standard foam for rodent exclusion, but still should not be used as the sole exclusion material for large gaps — use Xcluder first to fill the gap, then foam over it as a surface seal.
The gap under exterior doors — especially garage doors — is the #1 most common mouse entry point in residential structures. A standard hollow rubber door sweep compresses over time and allows gaps of ¼ inch or more to develop at the corners. The Pemko 270A uses an aluminum channel with a replaceable vinyl sweep that makes full contact with the threshold — it is the standard sweep used in commercial rodent exclusion work.
For garage doors specifically: the rubber threshold seal (Clopay and Genie make replacements) along the full bottom of the door is the critical element — the bottom corners where the door meets the floor are the primary mouse entry points. Replace worn threshold seals whenever light is visible underneath when the door is closed.
Walk the entire exterior of the home in the evening with a flashlight. Mark every gap ¼ inch or larger. Don't forget: utility penetrations through the foundation, the sill plate-foundation junction (often not flush), where pipes enter the wall, where electrical enters through the eave, weep holes in brick, and the corners of garage door frames. Inside: check under sinks, around all supply lines, at the junction of cabinets and walls, and where the floor meets exterior walls in basements and crawlspaces. Seal every marked gap before trapping — otherwise you replace trapped rodents indefinitely.