How to rodent-proof your house: a Metro Vancouver checklist

Phase 1: assess before you seal

Pick a day with good light and a flashlight. Walk the entire perimeter of your home from the outside. Carry painter's tape and a notebook. Mark every gap you find that's larger than 6 mm — the diameter of a standard pencil. Photograph each so you can match material to gap when you start sealing. The biggest mistake homeowners make is starting to seal before they've fully mapped the entry points; you'll run out of one material partway through and forget the locations you found earlier.

Phase 2: roof line and high elevation

Soffit-fascia gap: install aluminum drip-edge trim along the full length where the soffit meets the fascia. Hardware-cloth backer if the gap is over 12 mm.
Gable vents: retrofit a 19-gauge galvanized hardware cloth panel with quarter-inch mesh behind the existing louvres. Screw, don't staple.
Ridge vents: replace if the baffle is damaged. Inspect after high winds.
Roof returns: pack with steel wool and seal with closed-cell foam. Inspect annually because moisture eventually degrades the foam.
Roof penetrations (plumbing stacks, exhaust vents): replace any rubber boot showing cracks. Use roofing-grade flashing tape over any compromised flashing.

Phase 3: walls and exterior penetrations

Utility entries (water, gas, cable, A/C lines): pack steel wool around the pipe, then closed-cell expanding foam over the wool. Trim flush.
Dryer vent: install a metal louver damper that closes when the dryer is off. Cheap plastic versions stick open.
Bathroom and kitchen exhaust vents: same as dryer vent.
Basement windows: replace any rotted wood frames; install metal mesh under window-well covers.
Garage door bottom: replace the brush seal every 5 years. Add a threshold strip if the floor has settled.
Door bottoms (interior-to-garage, exterior, basement walkout): replace rubber sweeps every 3-5 years in BC's wet climate. Keep the sweep flush with the threshold.

Phase 4: foundation and crawlspace

Crawlspace vents: 19-gauge galvanized hardware cloth, quarter-inch mesh, screwed (not stapled) inside the existing vent grille. The most important single barrier on a BC home.
Foundation cracks: hydraulic cement on narrow cracks (under 6 mm); larger cracks need mesh + cement or polyurethane caulk over backer rod.
Sewer lateral cleanout: ensure the cap is intact and at grade level. Replace if settled below grade.
Sump pit: cover if uncovered. A loose cover allows soil-to-basement rodent access.
Deck-to-house junction: pack the rim-joist gap with steel wool and foam from underneath the deck.

Phase 5: tree canopy + landscaping (roof rat protection)

Trim back any tree branches within 1 m of the roof line. Cypress, cedar, fir, and big-leaf maple are common roof rat highways in Vancouver west-side.
Inspect hydro lines for chew marks and rat sign — roof rats use them as runways.
Move firewood, mulch piles, and dense shrub bedding at least 1 m from the foundation.
Keep grass and ground cover trimmed within 30 cm of the foundation perimeter.

Phase 6: interior reinforcement

Behind every appliance: check pipe penetrations, seal any gaps with steel wool and foam.
Inside cabinets where pipes enter: same.
Attic-to-soffit access: confirm soffit baffles are properly seated.
Around plumbing and HVAC penetrations between floors: pack with steel wool, seal with foam.
Garage-to-house door: confirm weather seal is intact, especially at the bottom corners.

Frequently asked questions

How much does professional rodent-proofing cost?+

A typical Metro Vancouver detached home runs $800-$2,500 depending on size, roof complexity, and existing condition. The high end usually involves substantial roof line and dormer work on heritage stock. The cost recovers fast because permanent exclusion replaces years of recurring trap-and-bait cycles.

Can I rodent-proof in winter?+

Mostly yes. Closed-cell foam needs above-freezing temperatures to cure; hardware cloth installation is fine year-round; caulking has temperature ratings on the tube. October-November is actually the best time in BC because the seasonal rodent push hasn't fully arrived yet but the weather is still workable.

What materials should I avoid?+

Steel wool alone (rusts in BC moisture), expanding foam alone (rats chew through it), copper mesh (more expensive than stainless and not noticeably better), spray-on sealants without backing material. The reliable system is steel wool packed first, foam over, hardware cloth as a hard barrier where appropriate.

Will rodent-proofing help with bugs and other pests?+

Yes — entry points used by rodents are also used by carpenter ants, cockroaches, and occasional invaders. A properly sealed building envelope reduces all pest entry, which is why our quarterly subscription includes exclusion as standard rather than an upsell.

The materials that fail (and why people keep buying them)

Hardware stores sell expanding foam and weatherstripping caulk as the solution for gaps and drafts. Neither works as a rodent barrier. Expanding foam is polyurethane — rats chew through it in hours when motivated. Steel wool alone rusts in Metro Vancouver's wet climate within a season, crumbling and leaving the gap open again. Copper mesh doesn't rust but has no significant advantage over stainless steel and costs more. Spray-on crack fillers and flexible caulks are intended for thermal sealing, not pest exclusion. The materials that last: 19-gauge galvanised hardware cloth (or stainless steel mesh for coastal applications where salt exposure is relevant), closed-cell expanding foam used as a backer behind mesh (not as a standalone barrier), and aluminum or galvanised flashing for linear gaps. These aren't exotic — they're all available at Rona or Home Depot. The issue is knowing to use them together rather than substituting one for another.