Rodent Exclusion and Rodent-Proofing on Long Island

• Full exterior inspection at ground level and roofline: foundation, sill plate, siding gaps, utility penetrations, vents, garage door, crawl space access, and the roof edge for squirrels and rats that climb.
• Interior inspection at the places the CDC lists: gaps around pipes under sinks and behind appliances, around water heater and furnace pipes, floor drains, and door and window frames.
• Sealing every opening larger than a quarter inch, which UC IPM says is the threshold to exclude both rats and mice.
• Materials by opening: copper mesh or hardware cloth packed and backed with sealant for small gaps, quarter inch hardware cloth over vents and crawl space openings, metal flashing or sheet metal at corners and sill gaps, and cement or mortar at foundation holes. The CDC's list is steel wool with caulk for small holes and lath screen, metal, cement, hardware cloth, or metal sheeting for larger ones.
• Door sweeps and garage door seals where the gap is the entry.
• A written map of what was sealed and where, so you and any future inspector can see it.

Because a trap catches the mouse that is already inside, and the hole lets in the next one. The CDC says mice can fit through a hole the width of a pencil, a quarter inch, and UC IPM says rats, especially young rats, can squeeze beneath a door with only a half inch gap. UC IPM is also clear about what does not hold: steel wool is a good temporary plug but rusts, and plastic screening, rubber, vinyl, expanding foam, wood, and other gnawable materials are ineffective. Rats can chew through plastic, foam, wood, and caulk. Sealing with metal and concrete is what holds through the next ten Octobers.

Inspect and mark. Every entry point, inside and out, is found and marked before anything is sealed.

Confirm the house is empty of rodents, or run trapping first. Sealing a rodent inside is how you get a smell in the wall. On active jobs, trapping and exclusion run together and the final seals go on when the monitors read zero.

Seal with the right material for each opening. Mesh and sealant, hardware cloth, flashing, or cement, matched to the gap.

Document. You get the written map of the work.

• Keep bulk food, bird seed, and pet food in metal or hard plastic with tight lids; the CDC and Illinois DPH both list them as attractants.
• Move the woodpile. The CDC's guidance is 100 feet from the house and a foot off the ground; on a Long Island lot, as far as the property allows.
• Trim branches off the roof so rats and squirrels lose the runway, and keep shrubs off the siding.
• Fix the door sweep the day it tears. It is the most common entry we find on a house that was otherwise sealed.
• Watch the fall. UC IPM says mice enter homes in autumn when nighttime temperatures drop, so a September walk-around with a flashlight is worth more than a January call.

• Oyster Bay
• Huntington
• Port Washington
• Massapequa
• Babylon
• Northport
• Long Beach
• Bayside
• Riverdale