The Labor Day Checklist: The Garage, Shed, and Weatherstripping Gaps Pests Use to Get In

Almost every pest problem we get called about started as a gap somebody walked past a hundred times. Not a dramatic hole — a worn rubber seal at the bottom of a garage door, a dryer vent whose flap stopped closing years ago, a half-inch of daylight at the corner of a crawlspace screen. The pests did not force their way in. They found an opening that was already there, in a house that looked perfectly closed up from ten feet away. Labor Day weekend is a good time to go find yours, because the work is genuinely a weekend project and because what comes next in the calendar — cooling nights, the first rain — is exactly what drives things indoors.

Exclusion work is worth doing at any point in the year, but there is a reason this particular weekend is the one we point people at.

What follows it is the seasonal shift that produces our heaviest call volume. As nights cool through September and October, rodents that spent the summer perfectly comfortable in ivy, woodpiles, and palm crowns start testing structures for somewhere warmer. When the first real rain arrives, everything living in soil, mulch, and ground cover moves at once — ants, spiders, roaches, earwigs — and they move toward the nearest dry void. Both of those events find whatever openings your house has. Neither of them creates new ones.

So the gap you close in the first week of September is a gap that is not available in November, which is the entire point. Exclusion is the only part of pest control that gets more valuable the earlier you do it.

If you only do one section of this list, do this one. More pests enter Southern California homes through the garage than through any other single part of the structure, and the reasons compound: it is the largest opening in the building, it opens and closes several times a day, its seal is a wear item that nobody replaces on a schedule, and it usually connects to the living space through a door that was never weatherstripped properly.

Once the garage is handled, walk the full perimeter of the house slowly and look at every point where something passes through an exterior wall. This is the category that produces the most surprise, because these openings were made deliberately by a trade that had no reason to care about pests.

The subarea and the attic are where a small entry becomes a large problem, because both are quiet, undisturbed, and mostly unvisited. They are also where the damage that shows up on an inspection report is generated.

On a raised foundation, walk the perimeter and check every foundation vent. The original galvanized screening rusts through at the edges, and it is common to find a vent that looks intact from three feet away and has a fist-sized opening at one corner. The crawlspace access door is the other classic — they warp, the latch stops engaging, and they end up propped rather than closed.

Up top, the items worth looking at are the attic and gable vents, the ridge and eave venting, and the roof-to-fascia line. Roof rats are the relevant pest here and they are excellent climbers, so height is not protection. Anything that lets a tree branch, a fence top, or a utility line put an animal onto the roof turns every gap up there into a usable entrance. Check where different roof planes meet, and where the gutter meets the fascia board — gaps at those junctions are extremely common on older South Bay housing stock.

Last, because these are the smallest openings, but worth doing because they are the ones you interact with daily and therefore the ones that annoy you most when something gets through.

Most of this list is genuinely a homeowner job with a caulk gun, a roll of hardware cloth, and an afternoon. Some of it is not, and the difference is worth knowing before you spend a weekend sealing something that will reopen.

Treat it as a symptom rather than a gap when: a screen or vent keeps being torn open in the same place, which means something is actively working at it rather than passing by; the wood around an opening is soft, crumbling, or stained, which is a moisture or wood-destroying-organism question before it is an exclusion question; a crawlspace access or vent frame is sagging out of square; or you are finding droppings, gnaw marks, or insulation debris inside, which means the sealing decision is now about what you would be sealing in.

That last one deserves emphasis. Closing a structure that already has an active rodent population inside is the wrong order of operations, and it produces exactly the outcome nobody wants — animals dying in inaccessible wall voids. This is why our own rodent work prioritizes mechanical exclusion and trapping inside the structure rather than poison bait indoors, and why a proper exclusion job establishes what is currently inside before it starts closing things. Find out first, then seal.