Where rodents get in.
A house has dozens of small openings, and most are invisible from the ground. The typical entries cluster around utilities, rooflines and doors. A technician walks the exterior with a flashlight and a probe, looking for daylight, gnaw marks and greasy rub smears.
| Gap type. | Barrier chosen. | Remarks. |
|---|---|---|
| Gap around a pipe sleeve. | Copper mesh packed in, collar of sheet metal. | Sealant locks the edges. |
| Open dryer or bath vent. | Screened metal hood. | Replace plastic flaps that no longer close. |
| Soffit seam at the roof edge. | Hardware cloth under trim. | Sized to the width of the gap. |
| Garage door bottom corner. | New gasket, metal kick plate. | Check the slab for erosion. |
| Crawl space vent. | Quarter-inch mesh in a frame. | Allows airflow, blocks teeth. |
The right sequence.
Sealing follows a sequence. Trapping or confirmation comes first, so no animal is locked in. Large openings are closed next, then small ones, working from the ground up. Finally the technician looks again for fresh signs near each patch.
- Confirm the animals are out, either by catches or by a quiet trap line.
- Close ground-level openings first, since they are the most used.
- Move up to vents, soffits and roof edges.
- Seal utility penetrations last, using metal collars.
- Inspect each patch at the recheck.
Why material matters.
Rodent incisors grow continuously and are kept sharp by gnawing. Soft materials give them something to work on. Metal, masonry and cured mortar do not, so a repair made from those lasts for years where a foam bead lasts a few days.
Mesh sized to a quarter inch blocks mice and rats while allowing airflow. Where a code or a product label restricts how much ventilation a vent must keep, the technician matches the opening to the original.
Easy exterior chores.
Trim limbs that reach the roof, since a branch is a bridge. Rake mulch back from the foundation so the sill is visible. Check that the garage door seal sits flat on the floor, and replace it if daylight shows.
Do not stuff holes with paper or rags. A rodent pulls them out within a night, and you lose the evidence of where the animal was working.
Awake at 2 a.m. and hearing scratching? Call anyway.
(888) 686-4821Additions, bump-outs and older frames.
Buildings of mixed ages, from the Schenck-Mann House of about 1700 to postwar ranches and newer infill, tend to have joints where old and new work meet. Those seams settle and open over the years, and mice use them. When you describe your house, mention any addition, converted porch or finished garage, because the technician inspects those junctions closely before closing them.
Cleanup rules from public health agencies.
If waiting for the crew is not an option, go through the items in order and stop whenever something seems unclear.
- Dry droppings crumble easily, which keeps the broom and shop vacuum in the closet.
- Airing out a closed room for about thirty minutes is the first CDC move.
- Put gloves on at the beginning, and close out the job with soap and water.
- Disinfectant needs time to work, so wait several minutes after spraying before wiping.
- Use a second bag if the first one is thin or heavy.
- Feeling off afterward? Tell a doctor what the cleanup involved and let the doctor judge.
Agency wording in full.
Full text lives at the links below.
- CDC tips to seal homes against rodents: Where the sealing and tidying suggestions on this page come from.
- CDC instructions for rodent mess indoors: Air out, soak, bag: this is the order the CDC publishes.