Walk into any kitchen in late June and you'll find the same thing: a thin line of ants marching along the baseboard, a wasp tapping the window over the sink, and a homeowner who just bought their third can of spray this month. Spraying is the part everyone does. It's also the part that barely works, because the bugs aren't living in your kitchen — they're getting in through gaps you've never looked at, and they'll keep coming as long as the gap is open.
Peak pest season in most of the country runs from late June through August, when soil temperatures climb past 70°F and colonies are foraging hard. The good news is that the real fix isn't chemical, it's structural. A house is a leaky box, and a few hours of sealing the right openings does more than a season of spraying. This is exclusion work — closing the doors instead of fighting the guests already inside — and it's the single most effective thing a homeowner can do before the heat fully sets in.
Start with the gaps you can feel, not the ones you can see
The instinct is to look for holes. The better method is to feel for air. Most pest entry points are also air-leak points, so on a hot afternoon, run the back of your hand slowly around the frame of every exterior door. Where you feel warm air pushing in, you've found a gap wide enough for an ant, and usually for a lot more. A standard interior door has a sweep at the bottom; an exterior door needs one too, plus weatherstripping on the sides and top. If you can see daylight under your front door, that's a gap roughly an eighth of an inch — wide enough for a mouse to flatten itself through, never mind insects.
A door sweep from Home Depot runs about $8 to $15, and the brush-style ones seal better against an uneven threshold than the rigid vinyl kind. For the sides, a roll of M-D Building Products foam or rubber weatherstripping is around $6 to $12 and installs with a peel-and-stick backing in under ten minutes per door. Don't skip the garage's man-door — the door from the garage into the house is the most-ignored entry point in the whole building, and it sits right next to where ants and spiders already congregate.
The threshold under the garage door itself
The big overhead garage door has its own rubber seal at the bottom, and on most houses over ten years old it's cracked, curled, or chewed through at the corners. A universal garage-door bottom seal kit costs $20 to $35 and slides into the existing track. While you're down there, check the two side seals and the top — wasps love to build under the top weatherstrip of a garage door because it's warm, dry, and nobody ever looks up there.
Seal where pipes and wires enter the house
Every line that comes into your home — the water supply, the gas line, the dryer vent, the AC refrigerant lines, the cable and electrical conduit — passes through a hole drilled in your siding or foundation. Whoever drilled it made it bigger than the pipe so the line would fit, and almost nobody went back to seal the gap. These penetrations are highways. Go around the outside of the house and find every one of them; you'll typically have eight to fifteen.
For the gaps themselves, the tool depends on the size. Anything up to about a half inch, fill with a good exterior silicone caulk — GE or DAP both make tubes for around $6 that hold up to UV and temperature swings. For bigger voids, the kind where you can fit a pencil, use expanding foam, but here's the catch: standard expanding foam is soft, and mice and some insects will chew straight through it. For anything a rodent could reach, stuff the gap with copper mesh or steel wool first, then foam over it. Copper mesh from a hardware store is a few dollars and it's the one material a mouse won't gnaw.
The dryer vent deserves its own look. The flap on the exterior vent hood is supposed to close when the dryer is off, but lint gums it up and it ends up propped open all summer — an open four-inch tunnel straight into your laundry room. A replacement vent hood with a tight louvered or magnetic closure is $12 to $25 and it solves a pest problem and a draft at the same time.
Windows and screens: the failure is almost always the frame, not the mesh
People assume a torn screen is the problem, and sometimes it is. More often the screen is fine and the gap is around it — the screen frame doesn't sit flush in the window track, leaving a quarter-inch channel down each side. Mosquitoes and gnats pour through that channel all evening. Press each screen and watch whether it rocks in the frame; if it does, foam weatherstrip tape along the track edges takes up the slack.
If the mesh itself is torn, you don't need a whole new screen. A screen repair kit with a roll of mesh and a spline tool is about $15, and re-screening a standard window takes maybe twenty minutes once you've done one. For a window you open constantly, it's worth upgrading to a tighter mesh — standard fiberglass screen has openings around 1.2 millimeters, which stops houseflies but lets in no-see-ums and the smallest gnats. A "no-see-um" mesh with roughly 0.6-millimeter openings keeps those out, though it does cut airflow noticeably, so it's a trade you make on a porch screen, not on every window in the house.
The yard decisions that matter more than any spray
You can seal a house perfectly and still get overrun if the conditions right outside the wall are inviting. Mosquitoes don't travel far from where they hatch, and they only need a bottle cap's worth of standing water to breed — a single cycle takes about a week in summer heat. Walk the perimeter and dump anything holding water: the saucers under your potted plants, a sagging spot in a tarp, the kids' wading pool, a clogged gutter, the bottom of a recycling bin. A birdbath is fine if you change the water every few days; left alone, it's a mosquito nursery.
Mulch and firewood are the other two. A bed of damp mulch pushed right up against the foundation is a comfortable, humid runway for ants, termites, and earwigs. Pull mulch back so there's a few inches of bare gap between it and the siding, and you make the wall far less appealing. Stacked firewood against the house is a classic mistake — it's a hotel for carpenter ants and spiders, and it should sit at least 20 feet away and up off the ground. None of this requires a product. It requires an afternoon and a willingness to move some things you've gotten used to ignoring.
When to actually call a professional
Exclusion handles the everyday stuff. There are a few things it doesn't, and pretending otherwise wastes your summer. Carpenter ants showing up indoors repeatedly — especially the big black ones with wings — can signal moisture-damaged wood inside a wall, and that's a job for someone who can find the source. Any suspicion of termites (mud tubes on the foundation, wood that sounds hollow) is a call-the-pro situation immediately, not a caulk situation. A wasp nest larger than a golf ball, or one inside a wall void where you hear buzzing but can't see the nest, is worth the $150 to $300 a pest company charges rather than a ladder and a can of spray at dusk. Knowing the line between a sealing job and a professional job is part of doing this well.
A realistic weekend plan
Treat this as one Saturday, not a summer-long campaign. Spend the morning on the perimeter walk: find your pipe penetrations, check the dryer vent, dump the standing water, pull the mulch back, and note every door and window that needs attention. Make one hardware run with the list — caulk, a door sweep or two, weatherstrip tape, copper mesh, maybe a garage-door seal — and you'll spend somewhere between $60 and $120 depending on how many doors and how rough the garage seal is. Spend the afternoon installing. By evening you've closed the entry points that a whole season of spraying never touched, and you've done it once instead of every week until September.