Why Rat-Proofing Matters as Much as Treatment
Eliminating a rat infestation without addressing how they got in is a temporary fix. Within weeks, a new population can establish itself through the same entry points. Rat-proofing — sealing the physical access points that rodents exploit — is the only way to achieve lasting protection.
Understand How Rats Get In
Before you can rat-proof your home, it helps to understand rodent capabilities:
- Rats can squeeze through gaps as small as 20mm (the size of a 50-cent coin)
- Mice can squeeze through gaps as small as 6mm
- Rats can climb brick walls, drain pipes, and rough surfaces with ease
- Roof rats (Rattus rattus) are agile climbers that commonly access homes through roof overhangs and tree branches
- Rats can gnaw through wood, soft concrete, plastic and aluminium
Common Entry Points to Seal
Roof and Eaves
- Gaps where the roof meets the eaves (fascia boards)
- Broken or missing roof tiles
- Open roof vents without mesh covers
- Gaps around pipes, cables and antennas entering through the roof
Walls and Foundation
- Weep holes in brick veneer (these need to stay open for ventilation but can be fitted with weep hole covers)
- Gaps around plumbing and electrical penetrations
- Cracks in the foundation and external walls
- Gaps under garage doors
Doors and Windows
- Gaps under external doors — fit brush or rubber door sweeps
- Damaged fly screens on windows and vents
- Gaps in sliding door tracks
Subfloor
- Open subfloor vents without mesh
- Gaps around plumbing penetrations through the floor
- Cracked or missing concrete footings
Best Materials for Rat-Proofing
- Steel wool / stainless steel mesh: Rats cannot chew through it — pack into gaps before sealing
- Concrete or mortar: For gaps in foundations and walls
- Metal kick plates: On the base of timber doors to prevent gnawing
- Hardware cloth (galvanised mesh): For larger openings like subfloor and roof vents
- Silicone or polyurethane sealant: For smaller gaps around pipes — use after packing with steel wool
Avoid: Expandable foam alone — rats can chew through it. Always combine with a physical barrier like steel mesh.
Garden and Outdoor Measures
- Trim tree branches so they do not overhang the roof (rats use these as bridges)
- Remove wood piles, debris and clutter from against the house — these provide harbourage
- Use metal bins with lids for compost and household waste
- Don’t leave pet food outside overnight
- Keep the yard clear of fallen fruit
When to Call a Professional
Professional pest controllers can conduct a full perimeter inspection to identify every entry point — including those not visible to the untrained eye. They can install physical exclusion materials, treat active infestations and advise on property-specific vulnerabilities.
Pestyologist provides rodent proofing and treatment across Sydney. Book an inspection today.