Air Gaps, Cracks, and Crevices: Sealing Your Home Against Pests
Walk around an older house at dusk with a flashlight and you quickly realize the place breathes through a hundred small openings. That breath invites life. Ants follow the humid trails, spiders set up in the eaves, wasps find the soffit gaps, and rodents treat the quarter-inch space under the garage door like a key to the city. I have spent plenty of evenings on ladders and under porches learning where pests slip through and how to keep them out without turning a home into a sealed jar. The goal is not hermetic perfection. It is good exterior hygiene, smart material choices, and careful workmanship where it matters most.
Why pests get in and what “sealed” really means
Pests push into buildings for three reasons: food, water, and a safe microclimate. They do not need a hole you can see from the street. A mouse compresses its body to fit a gap the size of a dime. A German cockroach can squeeze through a crack as thin as a credit card. Carpenter ants do not need a door, only damp wood and a hairline route from soil to sill.
When professionals talk about sealing a house, they mean two overlapping efforts. The first is exclusion, which prevents entry by closing and screening openings. The second is moisture management, which reduces the conditions that attract pests and let them thrive. A tidy kitchen matters, but on the construction side, gutters that don’t dump water against the foundation matter just as much. On a good day, sealing work cuts pest pressure and lowers energy waste by the same stroke.
Know your adversaries by their preferred pathways
Different pests prefer different highways. If you understand those routes, you stop taking random swings and start placing effective blocks.
Ants like predictable edges. They trail along foundation ledges, siding laps, plumbing penetrations, and landscape borders. They need moisture, so look for them near hose bibs, air conditioner lines, and bath vents where condensation often occurs. Once inside, they follow baseboards and pipe chases.
Cockroaches hitchhike on boxes and appliances, then fan out through kitchen and bath voids. They move behind refrigerators, in the warm space around dishwashers, through gaps at cabinet backs, and in the voids where plumbing meets walls. They also follow sewer and drain lines, which can let them pass between units in multifamily buildings.
Rodents prefer cover. They move through ivy, along fences and foundation shrubs, up downspouts, and across utility lines. They’ll gnaw almost any material softer than metal or stone. Garage door gaps and warped crawlspace hatches are common giveaways. So are unscreened weep holes, large A/C penetrations filled with soft foam, and soffit openings under loose fascia.
Spiders and wasps gravitate to sheltered, high places with intermittent airflow. They find attic vents, soffit gaps, and porch ceilings. If you see paper wasp nests under a second-story eave, look nearby for open lap joints or torn screens.
Termites and wood-borers focus on moisture, soil contact, and wood that stays damp. No amount of caulk replaces a proper termite barrier, but sealing cracks at slab perimeters and keeping wood off soil interrupts their exploration.
Each of these patterns suggests a map of priority zones, not an overwhelming checklist that treats every square foot as equal.
Walk the exterior like an inspector
I carry a bright headlamp, a putty knife, a screwdriver, a roll of painter’s tape, and a notepad. The tape flags issues without committing to a fix on the spot. The screwdriver and putty knife test materials. If I can sink either into a wood trim joint, there’s rot or poor paint maintenance that invites pests.
Start at the pest control las vegas ground and keep your eyes moving in a slow sweep. Look for daylight under doors, gaps between siding and trim, missing sealant around penetrations, and any place soil piles against wood. Pay attention to gradients. Water follows gravity, then pests follow the moisture trail. If a downspout dumps next to the foundation, that corner often grows gaps as materials swell and shrink.
Move up to the first-floor eaves. Poor soffit ventilation can be a two-way street for pests, and attic screens are the thin line between your insulation and a starling family. If you can run a finger around a vent and feel frayed mesh, plan on replacing it with heavier hardware cloth secured with screws, not staples.
Windows and doors deserve a slow look. Aluminum storm windows and older wood frames often have open weep holes. Those should be open for drainage but screened for insects, which calls for tiny mesh inserts or careful fabrications. Weatherstripping that looks intact may be too compressed to work. Close the door and look for light. If light gets through, so does air and whatever rides it.
An exterior walk takes patience and habit. On your second pass, it is easier to catch the small things, like the missing knockout plug in the corner of a junction box or the hairline gap where a PVC vent pipe enters stucco. Those little gaps become big annoyances later.
Materials that work, and the ones that disappoint
Sealing jobs fail in two main ways: the wrong material for the substrate or sloppy prep. A bead of top-notch sealant smeared over dirty, chalky paint will fail faster than a middle-of-the-road product properly applied to a clean, primed surface. The materials below have earned their keep.
High-quality exterior acrylic-latex caulk with silicone. Look for “elastomeric” on the label and a generous movement rating, often plus or minus 25 percent. It adheres well to painted wood, fiber cement, and some masonry, and it remains paintable. Pure silicone sticks tenaciously but resists paint, which is why I reserve it for color-matched, hidden areas, like behind trim or at metal-to-stone joints.
Polyurethane sealants. These cure to a tough, flexible rubber. They bond to masonry and metals, handle joint movement better than most caulks, and last a long time. They can be a bear to tool and clean up, and some yellow in sunlight. I use them where the joint matters structurally and where a durable seal buys peace of mind, like at a sill plate to slab joint under a threshold.
Backer rod. Foam rods fit into larger joints so the sealant sits in a proper hourglass profile rather than a deep wedge. The rule of thumb is a sealant depth roughly half the width of the joint, with a maximum depth around half an inch unless the manufacturer says otherwise. Without backer rod, you waste product and increase the risk of a brittle, three-sided bond that tears when materials move.
Expanding foam. There is a world of difference between generic “big gap filler” and pest-rated or low-expansion foams. Standard foam becomes a rodent’s chew toy. Look for foams labeled as pest-resistant and low expansion. Use them around window and door frames, sill plates, and pipe penetrations, where controlled expansion matters. For large penetrations, I often build a layered seal: hardware cloth anchored to framing, then foam as a filler, then a surface sealant that resists UV.
Hardware cloth and screens. For anything with a mesh, size matters. Quarter-inch hardware cloth keeps rodents out of vents and crawlspaces. For insects, smaller is better, but go too fine and you restrict airflow. A standard insect screen, around 18 by 16 mesh, keeps most flying insects at bay. For gnaw-prone locations, wrap foam or insulation with hardware cloth before cladding.
Flashing tapes and sheet metals. Sometimes the best seal is to shed water rather than block it with goo. A self-adhered flashing tape around a hose bib or at a meter base prevents water from getting behind the siding. A small aluminum drip cap above an exterior outlet or a trim board keeps the joint dry. Dry joints stay tight.
Weatherstripping and door sweeps. Closed-cell foam strips work for interior air sealing but degrade fast at exposed exterior doors. I prefer silicone bulb weatherstripping for jambs and a good aluminum sweep with replaceable rubber at the bottom. If you can slide a nickel between the door and threshold with the door closed, you need an adjustment or a new sweep.
Steel wool and copper mesh. Rodents hate pushing through steel wool, and copper does not rust. I pack either around pipes, then cap with sealant. On its own, packed mesh loosens over time. The combination holds, and it keeps gnawers from finding purchase.
The joints that matter most
I make a short list on every job, then work outward to less critical gaps. It helps to focus on joints that have both airflow and cover. Pests love an opening that is sheltered, because the wind does not dry it and predators leave it alone.
Foundation to sill plate. Where a wall meets a slab or stem wall, any continuous gap is a highway for ants and roaches and a draft that spikes your energy bill. If exposed on the interior, seal with a polyurethane or an acrylic elastomeric plus backer rod, depending on the size. On the exterior, this joint often hides behind the bottom course of siding or a water table trim. Where accessible, I run a small bead under the drip edge to stop air while allowing water to drain. Never seal weep systems in brick or manufactured stone. Those weeps exist for a reason.
Utility penetrations. Cable, gas, condensate lines, and electrical conduits often pass through oversized holes with a ragged smear of old sealant. Clean the area, insert a section of backer rod or mesh to control depth, and seal with a UV-stable product. For refrigerant line sets wrapped in insulation, rodents love that foam wrap. I slide a short sleeve of PVC or a metal escutcheon over the insulation where it enters the wall, then seal the sleeve perimeter.
Attic and crawlspace vents. Replace flimsy, torn screens with hardware cloth fastened by screws and washers. On crawlspace doors and hatches, add a compression latch and apply closed-cell gasket tape around the frame so it seals without sticking. If the crawlspace is vented, do not block ventilation entirely. Aim for secure screening and proper grading to manage moisture.
Garage door interface. That pencil-thin strip of daylight along the sides and bottom invites mice. Replace bottom seals that have stiffened. Adjust the tracks so the door presses evenly against the weatherstripping. If your driveway slopes, a simple aluminum threshold kit can create contact where the door misses high spots.
Eaves, soffits, and fascia. Any loose board or open return at a roof edge is a calling card for squirrels, starlings, and wasps. I replace rotted sections, prime all cuts, and back the joint with a drip cap. Semi-rigid soffit vents crack over time. If you can flex a vent with two fingers, it is likely too flimsy; upgrade to a heavier vent with a built-in screen or retrofit hardware cloth on the backside.
Windows and doors. Check the exterior casing to siding joint. If the original builder relied solely on caulk, it has probably failed. Where practical, add a small metal head flashing or a tape tucked under the siding above the head trim. Seal the vertical joints with a paintable elastomeric after cleaning and lightly sanding. On the interior, adjust latches so the weatherstripping compresses, not just touches.
Plumbing and under-sink gaps. Inside the home, the cutouts around pipes under sinks are often rough and oversized. Trim them with plates or escutcheons if you like a neat look, but from a pest standpoint, first stuff copper mesh around the pipe, then seal. Leave enough flexibility for future repair work by not gluing everything into a single hardened mass.
The moisture connection that most people miss
I worked on a house where ants returned every spring despite careful sealing. We finally traced the problem to a small garden bed against the south wall. The irrigation dripline soaked the soil, which wicked moisture into the sill through hairline cracks in the stucco. The sill stayed just damp enough to interest the ants and soften the caulk. The fix had three parts: pull the soil back to create a small air gap between bed and wall, add a gravel strip that broke the capillary path, and re-seal the stucco joint after drying the wall for a week. The ants lost interest.
Moisture is not simply rain. It is condensation on an A/C suction line, a slow drip from a hose bib vacuum breaker, and a gutter elbow that doesn’t seat fully, which dribbles during every storm. Each tiny leak adds a wet circle of opportunity. Before you reach for the tube of sealant, step back and make sure you are not trapping water pest control las vegas nv that needs a path out. Good sealing is often about steering water away and letting assemblies dry, not smearing over a damp joint.
Balancing airtightness with necessary openings
Not every gap deserves a bead of caulk. Drainage planes behind siding, brick weeps, and attic vents need to function. The trick is to protect them from pests without disabling their purpose.
Brick veneer weeps. Those open verticals at the bottom of a brick wall let water escape and air circulate. Plugging them invites trapped moisture and hidden rot. Insert purpose-made weep screens or stainless-steel mesh that blocks insects while preserving airflow. Keep mulch and soil at least a few inches below the weep course.
Attic ventilation. Ridge and soffit vents control moisture and temperature in the attic. Insect screen at the soffit and baffles to keep insulation from blocking airflow are the right tools. If bats are a concern, a one-way exclusion device combined with reinforced screening is the humane, effective approach. Permanent sealing without evicting the bats first simply moves the problem inside.
Dryer and bath vents. Use a tight-sealing exterior hood with a damper that actually closes. A louver that hangs open invites wasps, but you still need the vent to function. Inspect annually. Lint builds up around dryer hoods and attracts insects and mice. A quick scrub and a shot of compressed air make a difference.
How to execute clean, durable seals
Too many jobs fail for lack of prep. Good sealing work looks almost boring in how methodical it is.
- Gather the right supplies: a cleaning solvent appropriate to the surface, rags, painters tape, a high-quality caulk gun with a smooth rod, backer rod in two sizes, your chosen sealant, a utility knife, and nitrile gloves.
Mask edges when looks matter. A simple tape line creates crisp joints and keeps sealant from smearing onto siding texture. On rough masonry, tape is less useful, so practice steady tooling with a wet finger or a flexible spatula.
Cut the nozzle to match the joint, not the other way around. Most jobs need a small opening. Cut at a shallow angle and test on scrap before you touch the house.
Tool the bead promptly. Most elastomeric sealants gel within minutes. Press firmly to wet both sides of the joint and form that hourglass shape over the backer rod. Wipe excess onto a scrap piece of cardboard. Resist the urge to pass over the same spot repeatedly. Smooth once, then leave it.
Respect cure times. Just because a sealant skins over does not mean it is ready for paint or weather. Read the label. Some products need 24 to 48 hours before painting. If rain is in the forecast, hold off. A night of patience beats a week of repairs.
Document what you used, where. When the day comes to touch up, you will thank yourself. A small sketch and a note like “polyurethane at south sill, 3/8 inch with backer rod” saves you from guessing later.
Common mistakes that invite the very pests you’re fighting
I have seen great materials undone by small errors. The usual suspects show up again and again.
Overfilling joints with foam. Big gaps tempt big sprays. Excess foam bows trim, traps water, and leaves a crumbly surface that pests chew. Fill in lifts. Let the first layer cure, then add just enough to be proud of the surface so you can trim flush.
Smearing silicone over paint. Silicone needs a clean, compatible surface. On chalky paint, it peels like sunburned skin. If a previous homeowner applied silicone in the wrong place, remove it completely, clean the surface, and switch to a paintable sealant, or repaint before resealing.
Sealing over wet or moldy surfaces. Sealants do not cure correctly on wet substrates and mold simply grows under the skin. Dry the area thoroughly. Address the leak, clean with a suitable biocide if necessary, and only then seal.
Blocking designed drainage. If a joint routinely weeps water, ask why. The answer might be by design. Brick bottom joints, window weep holes, and some base flashing details should not be sealed. Instead, screen them with a purpose-made insert or mesh.
Ignoring the landscape. Mulch and foliage that press against siding are pest hotels. Even a perfect seal gets tested if a vine delivers ants to the second-floor soffit. Keep vegetation trimmed back by at least a foot. Maintain a mulch-free strip of gravel at the foundation.
Inside work that pays off
Sealing is not only an exterior task. Inside, you can cut off avenues and remove incentives that make the outside job easier.
Under- and behind-cabinet gaps. Pop off the toe-kick panels and look for open holes where pipes and wires come through. Pack with copper mesh, then seal. Wipe up spilled dishwater and crumbs that accumulate in those dark spaces. Small maintenance in the hidden areas stops roach expansion.
Attic and basement penetrations. Seal around light fixtures, bath fans, and plumbing stacks that pass through top plates. Those gaps create stack effect airflows that pull in insects from the perimeter and the crawlspace. In a basement, seal around sill plates and rim joists, then insulate. A warmer, drier rim discourages condensation and mildew that attract pests.
Door sweeps inside the garage. If you have a door from the garage to the house, treat it as an exterior door. Add a sweep and compressible weatherstripping. Garage pests otherwise wander into the conditioned space overnight.
Pantry and waste areas. Store grains and pet food in sealed containers. Wipe the inside rim of trash bins. A spotless kitchen is a myth, but a few habits remove long-term attractants, which strengthens the effect of your sealing work dramatically.
When to call a specialist
Most sealing tasks suit a careful homeowner or a capable handyman. There are times when the risks and regulations make a professional the better call. Suspicion of termites or carpenter ants in structural members calls for a licensed pest control operator. Wildlife in attics, especially bats or protected birds, require humane, legally compliant exclusion. Large masonry cracks that indicate settlement need an assessment before you dress them cosmetically.
An integrated pest management contractor can also audit your home and prioritize sealing tasks in a sensible sequence. In multifamily buildings, coordination matters. Sealing your unit while the neighbor’s remains a sieve shifts the traffic rather than solving the flow.
A seasonal rhythm that holds the line
I treat sealing as a habit, not a project with a finish line. Twice a year is a good cadence. Spring brings expansion as temperatures rise. Small gaps that developed over winter now show themselves. Fall is the time to close doors on rodents seeking warmth.
Keep a simple log of what you notice: the withered door sweep, the lifted flashing, the gap that reopens on the sun-baked west wall. Houses move. Sealants age. Screens tear. A maintenance rhythm, anchored by a few hours and a short shopping list, reduces surprises.
A real-world example, start to finish
A family called about mice in their kitchen, and we found several likely culprits. The home sat on a half basement, half crawlspace. The crawlspace access panel in the garage used a warped plywood cover with no gasket. The A/C line set penetrated stucco with a fist-sized hole filled long ago with soft foam. The garage door bottom seal had hardened and shrunk. Under the sink, a pair of one-inch gaps around the drain and supply lines opened into the wall cavity.
We tackled it in layers. First, the garage. We replaced the door sweep, adjusted the tracks for even contact, and installed a neoprene threshold to suit the sloped slab. At the crawlspace hatch, we built a new door with a solid frame, added closed-cell gasket tape around the perimeter, and installed a compression latch so it sealed tight without needing to be kicked into place. At the stucco penetration, we anchored a short length of PVC sleeve around the insulated line set, packed copper mesh into the remaining annulus, then sealed with a UV-stable polyurethane and a small stucco patch to blend it.
Inside, we stuffed the under-sink gaps with copper mesh and sealed with a paintable elastomeric. We added a sweep to the garage-to-kitchen door and replaced tired weatherstripping. We also trimmed back ivy that climbed the side wall and removed a mulch pile that had been heaped against the stucco, wicking moisture into the lower wall. Two weeks later, the traps in the kitchen stayed empty. Six months later, still empty. The house did not become a bunker. It simply stopped offering an easy path and an easy reward.
Simple checklist for a weekend sealing push
- Walk the foundation, flag gaps at penetrations, sills, and siding joints.
- Inspect soffits, attic vents, and fascia for loose sections and torn screens.
- Check all doors for light leaks, replace sweeps and adjust weatherstripping.
- Clean and seal utility penetrations with backer rod and appropriate sealant.
- Trim vegetation away from the house and pull mulch back from the foundation.
The payoff you feel and the problems you stop before they start
Most homeowners notice the quieter feel first. A sealed home muffles wind whistles and door rattles. Then comes the more even temperature and lower dust, because air and its freeloaders have fewer pathways. Pest sightings drop, not because you declared war, but because you removed the invitation.
I favor fixes that respect how a house works: water sheds, air moves, materials expand and contract. The best sealing does not fight those realities. It works with them, closing the unnecessary openings while leaving the necessary ones protected and functional. Once you see your home through that lens, the hunt for air gaps, cracks, and crevices becomes less about chasing pests and more about stewardship. The bugs and rodents get the message. They move on to the next house with the easy pickings. You get a tighter, drier, calmer one, and a few fewer midnight scrambles for the flashlight.
Business Name: Dispatch Pest Control
Address: 9078 Greek Palace Ave, Las Vegas, NV 89178
Phone: (702) 564-7600
Website: https://dispatchpestcontrol.com
Dispatch Pest Control
Dispatch Pest Control is a local, family-owned and operated pest control company serving the Las Vegas Valley since 2003. We provide residential and commercial pest management with eco-friendly, family- and pet-safe treatment options, plus same-day service when available. Service areas include Las Vegas, Henderson, Boulder City, North Las Vegas, and nearby communities such as Summerlin, Green Valley, and Seven Hills.
9078 Greek Palace Ave , Las Vegas, NV 89178, US
Business Hours:
- Monday - Friday: 9:00 AM - 5:00 PM
- Saturday-Sunday: Closed
People Also Ask about Dispatch Pest Control
What is Dispatch Pest Control?
Dispatch Pest Control is a local, family-owned pest control company serving the Las Vegas Valley since 2003. They provide residential and commercial pest management, including eco-friendly, family- and pet-safe treatment options, with same-day service when available.
Where is Dispatch Pest Control located?
Dispatch Pest Control is based in Las Vegas, Nevada. Their listed address is 9078 Greek Palace Ave, Las Vegas, NV 89178 (United States). You can view their listing on Google Maps for directions and details.
What areas does Dispatch Pest Control serve in Las Vegas?
Dispatch Pest Control serves the Las Vegas Valley, including Las Vegas, Henderson, North Las Vegas, and Boulder City. They also cover nearby communities such as Summerlin, Green Valley, and Seven Hills.
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Dispatch Pest Control provides residential and commercial pest control services, including ongoing prevention and treatment options. They focus on safe, effective treatments and offer eco-friendly options for families and pets.
Does Dispatch Pest Control use eco-friendly or pet-safe treatments?
Yes. Dispatch Pest Control offers eco-friendly treatment options and prioritizes family- and pet-safe solutions whenever possible, based on the situation and the pest issue being treated.
How do I contact Dispatch Pest Control?
Call (702) 564-7600 or visit https://dispatchpestcontrol.com/. Dispatch Pest Control is also on Facebook, Instagram, YouTube, Pinterest, and X.
What are Dispatch Pest Control’s business hours?
Dispatch Pest Control is open Monday through Friday from 9:00 AM to 5:00 PM. Hours may vary by appointment availability, so it’s best to call for scheduling.
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