Foundation & Crawl Space
Start low, because Norway rats come in low. Their burrows run along foundations and under woodpiles (UC IPM) and can drop 36 inches or more into the soil (University of Nebraska-Lincoln Extension). Chesapeake’s Property Maintenance Code expects foundation walls kept free of open cracks and tight enough to stop rodents.
Census estimates put 68.3% of Chesapeake’s housing units at 1980 or newer, yet in the ZIP code area that covers much of South Norfolk, 32.7% date from before 1960. Ticks here plus noise under the floor point to rodent control for the crawl space.
- A foundation crack or mortar joint a pencil slides into
- A crawl space vent screen that is rusted, torn or missing
- A crawl space access door that sits loose or will not close flush
- A burrow hole against the foundation, a stoop or the AC pad
- A gap where the siding or sill plate meets the top of the foundation
- Soil washed out from under a slab edge or step
- Stored items hiding the base of the wall
Doors & Garage
Doors fail at the bottom edge, and the garage door is the widest one on the house. UC IPM says a 1/2-inch clearance under a door is all a rat needs. University of Nebraska-Lincoln Extension sets the target below 1/4 inch and notes that rubber and vinyl weather stops do not hold up to gnawing.
Past the overhead door, a mouse has cover and time to work on the shared wall into the house.
- Daylight under or at the corners of the closed garage door
- A garage door bottom seal that is torn, chewed or lifts off the slab
- A gap behind the garage door’s side weatherstrip
- An exterior door with room underneath to slide a pencil through
- A gap down the middle where double or French doors meet
- A door sweep that is worn through, missing or gnawed
- An open gap around a pipe or duct leading from the garage into the house
- Chewed bags or droppings along the garage walls
Pipes, Cables & Utility Penetrations
Every line through an outside wall leaves a ring of open space around it. UC IPM names water, electric, sewer and drain lines among the openings to seal, and Virginia Tech’s guidance singles out air conditioning units, which give rodents warmth, water and a nesting spot.
Check what fills each ring. UNL warns that sunlight breaks down foam, and UC IPM counts expanding foam among the materials that fail against house mice. The entry-point guide covers each kind of opening in more depth.
- A gap wider than 1/4 inch around the HVAC refrigerant lines
- Foam around a pipe or cable that is chewed, holed or crumbling
- An open ring around a hose bib or water line
- A gap at the electric meter or the cable and phone line entry
- An old hole left where a cable or dish line was removed
- Open space around the gas line or AC condensate drain
- Indoors, gaps around pipes under a sink or behind the washer
Vents & Weep Holes
Vents and weep holes have to stay open, so look for a missing or flimsy cover. Pacific Northwest National Laboratory’s building guidance calls for corrosion-proof mesh no coarser than 1/4 inch on vents, except vents feeding an air handler, and UC IPM rules out chicken wire because rats pass through it.
Dryer vents need a working flap, not mesh: UNL notes that screening one the wrong way speeds up lint buildup. Brick weep holes drain the wall, so the fix is a screen that still lets water out.
- A dryer vent flap that is stuck open or missing
- An exhaust vent hood with a cracked or missing flap
- A vent covered with plastic screen or chicken wire instead of metal mesh
- A foundation or gable vent screen rusted or pushed through
- A gable vent with a bent louver or a gap around its frame
- An unscreened weep hole along the bottom course of brick
Roofline, Soffits & Attic
The roofline is where climbing rodents get in. Virginia Tech’s guidance lists eaves, roofs and attic vents as entry points, UC IPM calls roof rats “very agile climbers,” and UNL notes that brick, wood and concrete all give rats and mice enough grip to climb.
UC IPM’s branch distances are 3 feet from the roof, and 6 feet for limbs that hang over it. Live activity up there means our attic rodent work comes before sealing.
- A soffit panel that is loose, sagging or pulled away at a corner
- An open pocket at a roof return where a lower roof meets a wall
- A gap between the fascia board and the roof deck
- A rooftop plumbing vent wider than 2 inches with no screen on top
- A chimney with no cap or spark arrester
- A limb within 3 feet of the roof, or overhanging it within 6 feet
- A vine growing up the wall toward the eaves
- Droppings, tunneled insulation or daylight at the eaves in the attic
Yard, Vegetation & Food Sources
The yard decides what draws rodents toward the house. UC IPM’s figures run to 500 feet a night for Norway rats and past 300 feet for roof rats, and if your yard backs onto woods or water you cannot tidy beyond the fence. Our page on what draws rats to a yard goes deeper.
The City of Chesapeake collects bagged trash weekly from the City-issued container. Leaves, pine straw and grass clippings go out in clear bags on trash day, and bulk yard debris is one 4 x 4 x 6 foot pile a week, set out no more than three work days early. The EPA lists leaf piles and deep mulch as potential nesting sites, so keep waiting piles off the walls.
- A trash container with a chewed hole or a lid that will not close
- Pet food or birdseed kept in its paper bag in the garage or shed
- Pet food left out after your pet has finished eating
- Leaves, brush or yard waste bags piled against the house
- Firewood or lumber stacked on the ground or against the house
- Shrubs within 2 feet of the wall
- Mulch heaped deep against the foundation
Score Your Rodent Exposure
Your score is the number of items you ticked, shown in the bar as “N of 43 issues found.”
| Ticked | Band | What it means |
|---|---|---|
| 0 | No issues found | Nothing on the list showed up |
| 1 to 3 | A few openings | A short repair list in one or two zones |
| 4 to 8 | Several openings | Gaps across more than one zone |
| 9 or more | Many openings | Routes in at several levels of the house |
Treat the number as a rough guide. It is not a scientific risk score and it is not an infestation test. Every tick counts the same, and a score of 0 does not prove the house is free of rodents.
What to Fix First
Deal with signs of rodents inside first, then seal from the ground up. University of Nebraska-Lincoln Extension’s advice is to leave a hole open until you know whether it is in use, since sealing can shut rodents in.
| If you ticked | Do this | Why |
|---|---|---|
| Droppings, chewing, burrows or attic signs | Have the rodents removed first | Sealing an opening in use traps them inside |
| Foundation and door items | Close these next | Norway rats and mice work at ground level |
| Pipe and utility items | Fill the ring, then cover it with metal or mortar | Foam alone is not a barrier |
| Vent and weep-hole items | Screen or replace covers | They still have to move air or drain water |
| Roofline items | Plan for ladder work | Climbers reach them from walls and limbs |
| Yard items | Clean up as you go | Removes the draw, not the gap |
Steel wool buys time in a small hole, but UC IPM notes it can rust. For the rest, our rodent proofing service seals each gap with hardened material sized to it.
When to Book an Inspection
You need an inspection if you ticked any sign of rodents themselves, any roofline item or nine or more items, or found an opening you cannot tell is in use.
Chesapeake Rodent Control starts every job with a full interior and exterior inspection covering runs, droppings, burrows and every gap, vent and gnaw point. Exclusion and proofing is $180 to $250 per visit, and the price is confirmed before any work starts. Once the work is finished, the technician walks you through what was found, removed and sealed. Call (757) 551-3952 or request a free callback and bring your list.