Commercial Rodent Exclusion: How We Sealed a Restaurant Roof.

When a local restaurant owner started hearing scratching in the walls and finding droppings in storage areas, he knew he had a rodent problem. But trapping and baiting alone weren't going to solve it — the rats were getting in from the roof. That's where exclusion comes in.

What Is Pest Exclusion?

Most pest control focuses on treating what's already inside. Exclusion is the opposite — it's about finding every gap, crack, and opening where pests are getting in and permanently sealing them out. Think of it as fixing the hole in the boat instead of just bailing water.

For rodents especially, exclusion is the only long-term solution. Rats and mice can squeeze through openings as small as a quarter. If you're only trapping and baiting without sealing entry points, new rodents will keep replacing the ones you remove.

The Problem: A Commercial Roof Full of Entry Points

When we inspected the roof of this commercial restaurant building, we found what we often see on flat commercial roofs — multiple vulnerable entry points that rodents were actively using to access the building.

The issues included open pipe penetrations with no screening, gaps around HVAC equipment curbs, deteriorating roof membrane creating openings at wall junctions, and unsealed utility penetrations where plumbing and electrical lines entered the building. Every one of these was a potential doorway for rats.

Our Approach: A Systematic Roof Exclusion

We tackled this job methodically, working through every penetration and gap on the roof using professional-grade materials designed to hold up against both rodents and Pacific Northwest weather.

Pipe and vent screening was the first priority. We cut and formed 1/4-inch galvanized hardware cloth into caps and screens for every open pipe and vent on the roof. Each piece was secured with self-tapping hex head sheet metal screws spaced every few inches around the perimeter, then sealed with NP1 polyurethane sealant — the same commercial-grade sealant used by professional roofers and glaziers. The result is a permanent barrier that allows airflow but keeps rodents out.

HVAC equipment gaps were sealed using the same hardware cloth and screw method, custom-fit around each unit's curb and housing. Rats love the warmth that radiates from HVAC equipment, so these gaps are always high-priority targets.

Wall penetrations and irregular gaps were packed with copper mesh — a material that rats can't chew through — then sealed over with polyurethane sealant. The copper mesh gives the sealant something to grip inside the gap while providing a chew-resistant barrier. Together, the layered system is virtually impenetrable.

Membrane repairs at roof-to-wall junctions and around equipment curbs were sealed with flashing tape and sealant to close off any remaining routes.

Why Materials Matter

Not all exclusion work is created equal. We've seen DIY attempts using spray foam alone — rats chew right through it, sometimes within days. Foam is a sealant and weatherproofing layer, not a chew barrier. Proper exclusion requires physical barriers like hardware cloth or copper mesh that rodents simply cannot get through, combined with professional sealants that bond permanently to metal and masonry surfaces.

Every material we use is selected for durability in outdoor conditions. NP1 polyurethane sealant stays flexible through temperature swings, bonds to galvanized metal, and holds up against rain and UV exposure for years. Galvanized hardware cloth resists corrosion. Copper mesh doesn't rust and rats won't touch it.

The Result

After completing the exclusion work, every entry point on that roof was sealed. Combined with our ongoing interior rodent management program — including bait stations and monitoring — the building is now protected from both the outside in and the inside out.

The restaurant owner has peace of mind knowing that new rodents can't enter the building, and the existing population is being managed and eliminated through our regular service program.

Does Your Home or Business Need Exclusion?

If you're dealing with recurring rodent problems, there's a good chance they're getting in somewhere you haven't found yet. Common entry points include roof penetrations, gaps around HVAC equipment, utility line entries, foundation cracks, garage door seals, and crawl space vents.

At Orange Mango Pest Control, we don't just treat the symptoms — we find the source and seal it permanently. Our exclusion services are available for both residential and commercial properties throughout Bonney Lake, Tehaleh, Lake Tapps, and the surrounding areas.

If you're hearing scratching in the walls or finding droppings in your home or business, give us a call. We'll inspect, identify the entry points, and seal them for good.