Why is a rat problem usually outside the house?
Norway rats live at ground level in burrows, under sheds and along foundations, and they come indoors mainly to reach food or shelter. A rat seen inside usually means a burrow or runway outside, and the outdoor population is the source to deal with first.
The Illinois Department of Public Health describes Norway rats as the most common rat in urban and suburban areas. A rat in a south-suburb yard is often living in a burrow dug beside a fence, a garage, a shed or the foundation, and it may travel between several yards along the same line.
That makes the outdoor survey the most useful part of the visit. The burrow locations and the runways show where the animals live and how they reach the house, and the plan is built from those marks.
How is a rat different from a mouse in the yard?
Rats are heavier, dig more, chew harder materials and use ground-level routes, while mice climb and travel inside walls. The control for a rat therefore starts outdoors with burrows and food, and it needs sealing methods that resist chewing.
A mouse can fit through a gap a rat cannot, but a rat can enlarge a gap a mouse could not, by gnawing or digging. For that reason the exclusion is built from materials such as metal mesh and cement, not from a soft filler that a rat can chew out in an evening.
The bait and trap sizes also differ. A rat-sized station is placed along the ground route, and a mouse-sized trap sits along the wall. Using the wrong size or position is a common reason for a rat job to fail.
What food draws rats to a suburban lot?
Open garbage, compost, spilled birdseed, pet food left outside, fallen fruit and the scraps from a grill are the main attractions. Rats will travel a considerable distance for a reliable food source, so removing the food is often as important as removing the animals.
A closed lid that is not fastened is not enough. Rats can lift lids and chew through thin plastic. A garbage enclosure with a secured lid and a clean area beneath it removes the easiest meal on the lot.
Bird feeders are the most common surprise. A feeder under the tree is a food source for rats that run along the fence, and it can be moved away from the house and the fence line with little effect on the birds.
How do you seal a foundation against rats?
Sealing against rats uses materials they cannot chew or dig through, such as metal mesh set in mortar or concrete, placed at openings in the foundation, around utility penetrations and at the bottom of vent screens. Sealing is done after the active rats are reduced.
Soft materials such as foam or simple caulk are not enough on their own, because a rat can chew through them in a short time. A technician uses hard materials and checks each joint, especially where a pipe passes through a block or brick wall.
Sealing is planned so that the animals are not closed inside. A rat sealed into a crawlspace or a cellar will find another way out or stay and damage the insulation, so the work is sequenced with the removal.
Can a neighbour's rats move onto my lot?
Yes. Rats travel along fence lines, sheds and drainage routes, so a rat population on one lot can reach the next within a short distance. The survey notes where the runways enter the property and whether the problem is shared with the neighbour.
Working with a neighbour who has the same problem is often more effective than working alone. The technician can explain which source is on which lot without assigning blame, and a shared plan can cover both sides of the fence.
A lot that is cleaned up while the neighbour's garbage and compost stay open will see rats return. The plan includes the sources the homeowner controls and states clearly which ones are outside the job.