What Is Rodent Exclusion?
Rodent exclusion is the work of sealing a building so rats and mice cannot get back in. Trapping deals with the rodents inside today; exclusion deals with the ones that would follow them. The Virginia Department of Health puts it directly: “The most effective and permanent rodent control is to keep rodents out of buildings.”
Skipping it tends to bring the problem back. University of Nebraska-Lincoln Extension reports that “rodents will reinvade structures through unsecured openings following rodent control programs.”
Order matters too. The same UNL guidance warns: “If there is any doubt about whether a hole or gap is being used by an animal, do not close the opening until the species has been properly identified and a control program has been decided upon.” So we identify the rodent, deal with the active population, and then seal.
Our exclusion work covers:
- Sealing every exterior gap and vent with hardened material cut to its size
- Fitting door sweeps
- Screening vents and weep holes so air still flows and water still drains
- Carpentry and foundation repair where the building itself has given way
Common Rodent Entry Points
The most common rodent entry points on a Chesapeake house are the joints where two materials or two parts of the building meet. Most of the city’s houses are newer: in the ZIP code area that covers much of Greenbrier, U.S. Census Bureau estimates show 80.7% of housing units were built in 1980 or later and 34.6% in 2000 or later. Newer construction still has these joints, and we work through them in three zones:
| Zone | What we check |
|---|---|
| Ground level | Foundation cracks, crawl space vents and access doors, brick-veneer weep holes, garage door corners, door thresholds |
| Wall | HVAC line sets, dryer vents, hose bibs, cable, gas and electrical entries, gaps behind exterior trim |
| Roofline | Soffits and roofline returns, gable and attic vents, plumbing vent stacks, chimneys |
The size that matters is small. Under UC IPM guidance, anything over a quarter inch gets sealed, and UNL adds that gnawing can quickly enlarge smaller crevices. For a closer look at each type of opening and how to spot an active one, see how rats and mice get into Chesapeake homes.
Materials We Use to Seal Gaps
We seal gaps with materials rodents cannot chew through, matched to the size of the gap and the rodent it has to stop. Our specifications follow University of Nebraska-Lincoln Extension’s recommended materials for rodent-proofing:
| Material | Specification | Where we use it |
|---|---|---|
| Hardware cloth (mice) | 24 gauge, 1/4 x 1/4-inch mesh | Vents and openings where mice are the target |
| Hardware cloth (rats) | 19 gauge, 1/2 x 1/2-inch mesh | Larger vents where airflow matters and rats are the target |
| Galvanized sheet metal | 24 gauge or heavier | Gnawed edges, door bottoms, pipe and wall barriers |
| Concrete or mortar | Rigid patch | Foundation cracks and masonry gaps |
| Copper or stainless steel wool | Tightly wedged | Gaps under 3/4 inch wide that cannot be closed another way |
What we do not rely on matters as much. UC IPM says “plastic screening, rubber, vinyl, insulating (expanding) foam, wood, and other gnawable materials are ineffective for plugging holes used by house mice,” and to “never use lightweight ‘chicken wire’, since rats can easily pass through wire openings.”
Caulk and foam still have a place, as filler. UNL’s method is to fill the void to stop airflow, then “install a gnaw-resistant barrier” over the gap. That is how we finish utility penetrations.
Crawl Space & Foundation Proofing
Crawl space and foundation proofing seals the lowest part of the house, where Norway rats and mice most often start. The City of Chesapeake’s Property Maintenance Code sets the standard: foundation walls “shall be maintained plumb and free from open cracks and breaks and shall be kept in a condition so as to prevent the entry of rodents and other pests.”
Foundation work has to account for burrowing. University of Nebraska-Lincoln Extension says rats “burrow straight down into the ground at least 36 inches,” so a crack at the base of the wall can connect to a tunnel well below the surface. We repair foundation gaps with rigid material and use exclusion carpentry where framing has been chewed or damaged.
Crawl space vents are there to move air, so we size the screen to the vent and the rodent, keeping the space breathing while the gap stays closed (see the FAQs below). Access doors get the same attention.
For removal and cleanup under the house as well as sealing, see our crawl space rodent control service.
Attic, Roofline & Vent Proofing
Attic and roofline proofing closes the high gaps that a ground-level seal misses. Virginia Tech’s pest guidance reminds homeowners not to stop at the first three feet of wall, since rodents also get in at the eaves, roof and attic vents.
Getting up there is easy: UNL notes rats and mice “climb almost any rough vertical surface such as wood, brick, concrete, and weathered sheet metal.” On a Chesapeake house, the roofline work usually means:
- Sealing soffit gaps and the returns where the roofline meets the wall
- Screening gable and attic vent grills with 18-gauge, 1/2-inch galvanized expanded metal or 16-gauge, 1/2-inch galvanized wire cloth, as UC IPM recommends
- Screening rooftop plumbing vent pipes over 2 inches in diameter
- Fitting chimneys with a spark arrester
Branches are the other way up. UC IPM advises pruning tree limbs within 3 feet of a roof and removing overhanging limbs within 6 feet to keep rats and tree squirrels off the roof top. If rodents are already living overhead, our attic rodent removal service clears the attic before the roofline is sealed.
Door, Garage & Utility Penetration Sealing
Doors, garage doors and utility penetrations are the mid-level gaps most homeowners never check, and each seal has to survive daily use as well as teeth.
Doors. University of Nebraska-Lincoln Extension says the gap between a door bottom and its threshold should be less than 1/4 inch, and that “rats and mice can quickly gnaw through rubber or vinyl weather stops.” Its fix is metal flashing on the lower edge of the door. UC IPM adds that double doors should be sealed at the astragal gap between them. We fit door sweeps and metal edging where the door needs it.
Garage doors. We inspect the bottom seal, the corners where it meets the frame and the wall between the garage and the house, and seal gaps there with chew-resistant material.
Weep holes. Brick-veneer weep holes need to drain, so we screen them rather than fill them.
Utility penetrations. HVAC line sets, cable, gas and plumbing entries are filled to stop airflow and then covered with a gnaw-resistant barrier. Virginia Tech advises sealing air conditioning units well, since they offer “warmth, a nesting site, and a ready source of water.”
Dryer vents. UNL warns that “clothes dryer vents require special treatment, as improper screening hastens lint build-up and increases the likelihood of fires,” so we never stuff mesh into a dryer vent. A proper vent cover does the job.
Rodent Exclusion Cost
Rodent exclusion with Chesapeake Rodent Control costs $180 to $250 per visit for exclusion and proofing. Where in that range a house falls depends on how many gaps the inspection finds and where they are.
| Service | Price per visit |
|---|---|
| Exclusion & proofing | $180–$250 |
| Follow-up visit | $99–$120 |
If rodents are still active, removal comes first and is priced separately: $99 to $149 for mouse inspection and treatment, or $150 to $220 for rat treatment. You get the exact figure on the callback, and when the sealing is finished the technician walks you through every point we closed.
Repairs, storms and new utility lines can open fresh gaps later. Our rodent proofing checklist for Chesapeake homes helps you spot them before a rodent does.