Exclusion and pest-proofing

Exclusion is the work of keeping pests out of a building for good. You find the gaps that rodents, bats, birds, insects and other wildlife use to get in, and you close them with materials the animal cannot chew through or squeeze past. University of California IPM calls exclusion, or 'building them out', the most successful and longest-lasting strategy for rat control around structures. The job is closer to light construction than to spraying: ladders, rooflines, crawlspaces, hardware cloth, sheet metal and sealant. It suits people who like building and fixing things, who are comfortable at height and in tight spaces, who notice small details, and who want work they can point at when the day is done. It is also a field with an unusual legal position. In some states, exclusion done without pesticides sits outside pest control law altogether. In others it needs a pest licence or a limited certificate, and contractor licensing can come into play on bigger jobs. BLS does not track exclusion as its own occupation, so pay figures here are honest approximations, clearly labelled.

Most days start at the truck. Exclusion crews carry more hardware than a typical pest route: extension and step ladders, sheet metal, galvanized mesh, steel wool, sealants, a drill and fasteners, and the personal protective gear for attics and crawlspaces. BLS describes pest control work in general as travel to a client's home or business, indoors and outdoors, in all types of weather, and that is exactly what exclusion looks like.

A large share of the work is inspection. You walk the outside of the building looking at the roofline, eaves, soffits and rafters, the foundation, vents, doors and windows without weather stripping, and every place a pipe, cable, gas line or electrical line goes through a wall. Inside, you look in attics, basements, closets, under sinks and behind appliances. These are the same places the CDC tells homeowners to check. The reason it takes so long is the size of the target: the CDC notes a mouse can fit through a hole the width of a pencil, about a quarter of an inch. You photograph and measure what you find, and on many jobs you also write the estimate. BLS lists measuring the area to be treated, estimating the cost of services and creating barriers to prevent pests from entering among the core duties of pest control workers.

Install days are hands-on. Small holes get steel wool held in with caulk or foam; larger openings get lath screen or metal, cement, hardware cloth or metal sheeting, which is the material list the CDC gives. Material choice matters more than it looks. UC IPM warns that rats can chew through plastic, foam, wood and caulk, recommends sealing every hole larger than a quarter inch to keep out both rats and mice, specifies 18-gauge or 16-gauge galvanized half-inch mesh for vent grills, and says never to use lightweight chicken wire. Much of this is done on a ladder at the roofline or on your knees in a crawlspace.

Exclusion rarely works alone, and the crew has to coordinate with whoever handles trapping or baiting. UC IPM advises minimizing entry points before baiting outside, so poisoned rats do not come inside to die. Where wildlife is involved, timing is set by the animal and by state wildlife law. Bat exclusion is the clearest example: Wisconsin prohibits bat exclusions from June 1 to August 15 to protect mothers and flightless pups, and Georgia says bat exclusions should be avoided between April 1 and July 31, with any exclusion in that window done by a licensed Nuisance Wildlife Control Operator. The dates are different in each state, so the schedule on a bat job comes from the local rule, not from the sales calendar.

The rest of the week is follow-up and paperwork: return visits to check that sealed points held and that no new activity has appeared, photos for the customer file, and notes for the technician who services the account. Weather decides a lot. Roof and ladder work stops when it is unsafe, and OSHA requires fall protection at four feet in general industry and six feet in construction, so the job plan has to account for height from the start.