Quick answer: Do not seal an opening just because an animal might fit through it. First establish whether it is a damaged gap, a ventilation opening, an appliance exhaust or a drainage outlet. Preserve the opening's function, and confirm whether animals or dependent young are inside before exclusion. If you cannot identify the opening, leave it unchanged and ask the relevant qualified professional.
A squirrel at the roof edge, a bird at a wall outlet and insects near a brick joint can look like the same problem: a hole that needs closing. The openings may do entirely different jobs. This guide helps you choose the next inspection question; it does not provide a repair specification or confirm an animal from a hole.
Start with two separate questions
- What is the opening for? Find its purpose from building or equipment records, or ask the relevant trade. Position and appearance are clues, not proof.
- Is it currently used by an animal? Record visible activity from a safe place. A quiet period does not confirm that a hidden space is empty.
Keep children and pets away from suspected entry points. Do not reach inside, remove a nest, push a tool into a duct or climb onto the roof to improve your view. Wildlife status and the building detail need separate checks.
Four openings that need different answers
On a phone, swipe this table to read the inspection questions. It compares functions, not universal hardware sizes.
| Possible opening | Function to confirm | What not to do | Next question |
|---|---|---|---|
| Soffit or attic vent | Air movement through the intended ventilation system | Pack it with foam or choose dense mesh without checking airflow | What compatible cover preserves the required ventilation? |
| Clothes-dryer outlet | Dryer exhaust with an opening flap or louvers | Add a screen that can collect lint, or run the dryer to drive an animal out | Has the outlet and duct been checked, and which unscreened termination is appropriate? |
| Brick weep opening | Drainage from a brick-veneer wall assembly | Fill it with caulk, mortar or foam | Can an appropriate pest guard retain the drainage path? |
| Damaged joint or gap around a penetration | Whether this is a defect rather than a required opening | Seal around an unknown pipe, appliance vent or flashing detail | Which building component is involved, and who should inspect it? |
Soffit vents: exclusion must preserve ventilation
Soffits are beneath the roof edge; not every soffit panel is a vent. DOE / PNNL describes durable, securely attached covers and warns that fine screening can restrict airflow. Do not choose one mesh size for every animal and every ventilation system. Ask the inspector to identify the actual entry route and explain how the proposed cover maintains ventilation.
A damaged roof-edge opening is not proof of a squirrel, and a visible adult does not establish whether young remain inside. If your first problem is an unexplained sound, use the attic sound comparison as a list of observations, not a diagnosis. Avoid disturbing the space to collect more clues.
Dryer outlets: do not add a generic screen
PNNL's dryer-exhaust guide explains that a screen can trap lint and obstruct airflow; it describes flap or louvered terminations without screening. A product sold as a general pest barrier is not evidence that it is suitable for your dryer's outlet.
If birds or nesting material may be inside a suspected dryer outlet, stop using the dryer pending assessment. Do not run it to test occupancy or clear the obstruction. Ask a qualified wildlife professional about the animal and an appropriate appliance or vent professional about the equipment. The bird-in-dryer-vent guide covers that specific situation; this article does not supply a nest-removal or duct-cleaning procedure.
Brick weep holes: a drainage opening is not missing mortar
In a brick-veneer drainage assembly, water needs a path out through weep openings. PNNL's wall-flashing guide explains that function and shows open-weave protection that preserves drainage. A repeating open joint can be intentional, but repetition alone does not certify what you are looking at.
Do not plug a suspected weep hole because insects are nearby. Ask a masonry or building-envelope professional whether it is a drainage opening, whether the drainage path is functioning and whether a compatible pest guard is suitable. Do not fill the cavity or drill a new opening based on this guide.
Unknown openings: identify the equipment before changing anything
A round hood on a wall does not identify the appliance it serves. Ventilation intake, dryer exhaust and combustion equipment must not be treated as interchangeable. Use equipment documentation or an appropriate qualified technician; local requirements and the manufacturer's instructions matter. This page does not specify covers for combustion exhaust, chimneys, gas appliances or electrical components.
For an animal at a chimney, see the chimney wildlife assessment guide rather than adapting a soffit solution. Do not block an unknown opening as a temporary experiment.
What to record without approaching the opening
- Its location: roof edge, wall, brick base or another surface.
- Visible condition from a safe position: displaced cover, damaged material or an unobstructed intentional opening.
- Dates and times of visible animal entry or exit, without inferring a species from hole size.
- Existing photographs, equipment model information and earlier work records, if already available.
- Any unknowns: hidden cavity, possible young, uncertain equipment or inaccessible area.
Send these observations to the appropriate professional and ask for the proposed work in writing. Do not enter a contaminated space or reach inside to complete the list.
Before approving exclusion
- Confirm the opening's function and the actual animal activity.
- Ask how occupancy and dependent young will be assessed, and which local wildlife rules apply.
- Ask why the selected barrier suits this opening, species and equipment.
- Have the provider explain how ventilation, drainage, service access and any moving flap remain functional.
- Request completion photographs, inspection limitations and any maintenance instructions.
These are homeowner questions, not a universal construction checklist. A wildlife provider may need to coordinate with another trade. Repairing one opening does not establish that every possible entry route has been addressed.
Frequently asked questions
Can I use expanding foam for any animal entry gap?
No. First distinguish a repairable defect from ventilation, drainage or equipment. Foam is not a universal exclusion specification, and an occupied cavity must not be sealed.
Is the smallest mesh always best?
No. Animal exclusion and airflow requirements must both be considered. Dryer exhaust is a clear example where a generic screen is not the answer.
Does a neat row of gaps prove they are weep holes?
No. It is a clue to check, not a diagnosis of the wall assembly. Have the function confirmed before changing them.
Should I close a gap when I no longer hear an animal?
Silence does not prove vacancy. Ask how hidden animals, young and other entrances will be checked before work.
Sources and review scope
- DOE / PNNL: Screens and Other Deterrents — opening-specific exclusion and airflow cautions.
- DOE / PNNL: Clean Dryer Exhaust — unscreened dryer termination; cleaning procedures are not reproduced here.
- DOE / PNNL: Flashing at Bottom of Exterior Walls — brick-veneer drainage and weep openings.
Sources checked October 3, 2026 (ET). The comparison and inspection questions are an editorial synthesis, not a property inspection, manufacturer approval or local-code determination. No field experience, construction dimensions, removal service or guaranteed outcome is claimed.