Walk around your house and count the small openings in the wall and the roof: dryer vent, bathroom fan, range hood, attic vents, crawl-space vents, and the cap on each plumbing stack. Every one of them is designed to let air out or in. Every one of them can also let a mouse in if the cover is missing, bent or loose.
The usual suspects.
| Vent. | Where. | Typical failure. |
|---|---|---|
| Dryer exhaust. | Exterior wall. | Flap stuck open or missing, cap gone. |
| Bathroom fan. | Wall or soffit. | Damper broken, screen torn. |
| Range hood exhaust. | Wall or roof. | Damper stuck, screen missing. |
| Attic vents (gable, ridge, soffit). | Roof or eaves. | Screen bent, torn or pushed aside. |
| Crawl-space vents. | Foundation. | Cover rusted or broken. |
| Plumbing stack. | Roof. | Cap missing or cracked. |
Start with the ones at ground level, since you can see them without a ladder. Then look at the ones on the roof from the ground, and use binoculars if you have them.
What to look for.
- A flap that hangs open or no longer closes.
- A cover that is missing or lying in the planter.
- A screen that is bent, rusted or pushed in.
- Droppings, grease marks or shredded material below the vent.
- Daylight visible from the inside through the opening.
If you see any of these, photograph the vent and note its location. A technician can then decide which material fits.
Why metal beats everything else.
Plastic covers crack in the sun. Mesh sold for screens is often thin enough to chew. Foam and caulk are soft. For vents that must breathe, the best answer is a formed metal hood or screen fastened with screws, and for vents that must stay clear, such as the dryer, a hood with a spring-loaded flap.
Fine mesh on a dryer vent is a fire risk, because lint builds up quickly. Use the right hood, and clean it regularly. The exclusion page explains how each type of opening is handled.
Attic and roof vents.
Gable vents, ridge vents and soffit vents usually have screens to keep out animals and insects. Over time the screens corrode or detach. A rat can pull a loose screen aside, and a mouse can pass through a torn corner.
These repairs often need a ladder and care on the roof. A technician replaces damaged mesh with stainless or galvanized screening that is screwed in, not stapled. If you can only reach the ones at ground level, note which ones you cannot see.
Narrate the problem to a live person and skip the web search.
(818) 791-1810Signs that an animal is already using a vent.
- Droppings or grease marks on the sill or siding below.
- Nest material visible in the duct.
- Scratching sounds that begin or end at the vent.
- A draft or smell coming from the opening.
Do not stick your hand inside a vent. Photograph what you see and call. If a duct is full of nest material, it needs to be cleaned before use, because blocked ducts can cause fires or moisture problems.
A note about tile and stucco.
Houses with tile roofs have gaps where tiles meet the ridge or the wall. Houses with stucco have seams around penetrations. Whatever material your house uses, the seam where one material meets another is a place to look. Some of those seams close with metal flashing or mortar-grade sealant.
We have no survey of how many homes in Agoura Hills use each material. The technician looks at what you have.
A twice-a-year routine.
- Walk the exterior in spring and fall.
- Test each damper by hand or watch it during a run cycle.
- Replace caps and flaps that are missing or loose.
- Photograph anything you cannot fix and keep the pictures for the call.
Ten minutes twice a year protects you from a surprising number of problems. If you find gaps, a short call gets a plan going, and the trapping page and inspection page explain what comes next.
Handling droppings without raising dust.
Dried rodent waste breaks into fine particles, so the safe way to deal with it is slow and damp. These steps follow public health guidance and apply even if you never book a visit.
- A single dry pellet can crumble at a touch and release a cloud you cannot see.
- Public health pages put airing out first on the list, with roughly thirty minutes as the benchmark.
- Gloves while working and soap afterward make a pair that protects you.
- Wet every inch you plan to touch, including the spot underneath the pellets.
- Seal towels, gloves and waste in a bag, then drop that bag into a second one before disposal.
- Washing is the final step, whether or not you wore gloves.
Federal pages behind the cleanup steps.
Open these when you want the full reasoning behind a step.
- CDC: wet-wipe method for rodent waste: Damp-cleaning directions for households, one move after another.
- CDC: seal up, trap up, clean up: Close holes, store food well and clear nesting spots around the home.