Rodent Proofing a Commercial Site
The entry points that matter most in commercial venues — and how to close them properly so a rodent problem doesn't come back.
Short answer
Rodent proofing is what turns a rodent control job into a job that actually ends. Trapping removes the animals on site; proofing removes the reason they can keep arriving. In commercial venues, the entry points that matter most are under doors, service penetrations, roof and eave gaps, weep holes and vents, drainage and floor wastes, and delivery doors that stay open during service. Effective proofing uses metallic or hard materials — steel mesh, escutcheon plates, sheet metal kick strips, mortar fill — not soft sealants alone.
Proofing should follow inspection and trapping, not precede them. Closing the wrong gap can push activity deeper into the building or trap rodents inside voids.
Why this matters
Proofing is the difference between control and a treadmill.
Control ends. Without proofing, every trapping success is temporary. The next rodent uses the same route the previous one used.
Audit and compliance. Auditors expect to see structural remediation, not just trapping. A proofing plan and completion records are part of a defensible pest program.
Building protection. Rodents gnaw insulation, cabling, packaging and stock. Closing the envelope also protects assets that are expensive to repair or replace.
Neighbour risk. Terrace, strip retail and multi-tenancy sites share walls, roof voids and drainage. A closed envelope on your side reduces exposure to a neighbour's problem.
What to do immediately
- Walk the perimeter with a torch. Look along the ground line for gaps under doors, damaged brickwork, weep holes and unsealed service penetrations. Note every gap wider than an adult thumb.
- Check the roof line externally. Eaves, flashings, vents and service entries are the most common high entry points. Use binoculars if the roof isn't safely accessible.
- Inspect drainage. Confirm floor wastes, gullies and grease trap access have intact covers. Note any disused pipework connected to active drainage.
- Photograph and log gaps. A short photo log with locations gives a technician a clear scope and forms part of the audit trail.
- Arrange a professional inspection. Ask for a proofing plan that identifies materials, priorities and staged works — not a general recommendation to "seal gaps".
Common mistakes
Using soft sealants alone. Silicone and expanding foam are useful backers, but rodents chew through them. Anything gnawable needs a metallic or hard layer.
Sealing before mapping activity. Closing a used route can trap rodents inside or push activity elsewhere. Proofing follows evidence.
Focusing only on doors. Under-door gaps matter, but rodents also use eaves, vents, weep holes, drainage and service penetrations. A door strip alone rarely fixes a commercial problem.
One-off proofing. Buildings move, seals age, deliveries damage frames. Without a periodic review, the envelope reopens.
How Ratman approaches this
Ratman's proofing follows the same commercial structure used across the site: evidence first, mechanical trapping, monitoring, then proofing.
Inspection
Full internal and external inspection maps every candidate entry point — ground line, roof line, service penetrations, drainage, delivery zones and shared boundaries.
Identifying causes
Not every gap is active. Rub marks, gnaw marks, droppings and grease trails identify which routes are in use so proofing can be prioritised.
Mechanical trapping
Traps are placed along active routes before proofing begins, so rodents on site are removed rather than sealed in.
Monitoring
Scheduled inspections confirm that closed routes stay closed, and identify new gaps caused by building movement, damage or renovation work.
Proofing
Steel mesh, escutcheon plates, sheet metal kick strips, brush seals, mortar and concrete fill. Damaged flashings, doors and drainage are referred for repair with a clear scope. Everything is documented in the site log.
When to call a professional
Some proofing is straightforward maintenance; other work benefits from a documented professional program:
- An ongoing rodent problem despite trapping — a sign the envelope isn't closed.
- An audit or council inspection has requested structural remediation.
- Multiple entry points across roof, walls and drainage that need coordinated works.
- Shared boundaries with neighbouring tenancies where proofing needs to be planned across the block.
- A new fit-out or renovation where rodent risk should be designed out from the start.
- A heritage or complex building where materials and access require specific expertise.
A documented proofing program gives you a mapped scope, priorities, materials and completion evidence — the record auditors, landlords and insurers actually want.
Frequently asked questions
How small a gap can a rat get through?
A rat can pass through a gap the width of an adult thumb — around 20 mm. A mouse needs only the width of a pencil, around 6–7 mm. Any gap you can push a biro through is a rodent gap. Assume anything larger is an active route.
Isn't silicone or spray foam enough to seal gaps?
No. Rodents chew through silicone, spray foam, plaster and untreated timber. Effective proofing uses a metallic or hard layer — steel mesh, escutcheon plates, sheet metal kick strips or mortar fill — either alone or backing softer sealants.
Should we seal every gap immediately?
Not before you know what's active. Closing a used route can trap rodents inside a void, push them deeper into the building or hide evidence needed to map activity. Proofing follows inspection and trapping, not the other way around.
How long does commercial proofing last?
Correctly installed mesh, escutcheon plates and metal kick strips typically last for years. What fails is soft sealant used alone, aged brush seals under high-traffic doors and building movement around service penetrations. A yearly proofing review keeps the envelope closed.
