Every spring, Homer Glen homeowners hear scratching and chirping echo down the flue. The lasting answer is not a one-time removal; it is the right exclusion hardware on top.
Removal is temporary; exclusion is permanent
Getting an animal out of a flue solves today’s problem. It does nothing about the open hole in your roof that invited it. An uncapped chimney is, from a squirrel’s point of view, a hollow tree with a perfect sheltered cavity, and from a starling or chimney swift’s view, a tall protected nesting shaft. Unless you close the entry point with proper hardware, the next animal moves in on the same schedule the following year. The job that matters is sealing the top correctly, and that is where this article focuses.
Jason Lecter has pulled enough nests out of local flues to know that the homes that stay clear are the ones with well-chosen, well-installed exclusion hardware. The pattern is predictable: a homeowner pays to have an animal removed, feels relieved, and then calls back a year later with the same scratching overhead because nothing ever closed the opening. Breaking that cycle costs less than repeating the removal, and it protects the flue from rain and embers at the same time. Here is what works and why.
The hardware that keeps wildlife out
- A properly sized chimney cap with spark-arrest mesh. This is the single most effective barrier. The mesh must be a gauge small enough that a squirrel cannot gnaw or squeeze through, yet open enough not to choke the draft. Flimsy aluminum caps fail because squirrels chew them; stainless mesh resists both teeth and rust. A cap also stops rain and embers, so it earns its keep year-round.
- Multi-flue cap or crown-mounted screening for chimneys carrying more than one liner, so no flue is left uncovered as a side door for birds.
- A top-sealing damper that closes the flue at the crown with a rubber gasket when the fireplace is idle. It seals out animals and drafts in one piece and replaces a worn throat damper that no longer shuts tight.
- Caulk-free, mechanically fastened installation. Hardware that is simply wedged or glued on gets dislodged by raccoons and heavy wind. We bolt or band caps to the crown so they stay put.
We size and fit all of this during our chimney cap and crown service, measuring each flue so the cap fits snugly rather than relying on a one-size big-box lid.
Timing, legality, and doing it right
There is a legal wrinkle worth knowing. Chimney swifts and many songbirds are protected under federal law, so if a nest is active with eggs or chicks, it cannot be removed until the young have fledged. The smart move is to cap the chimney in late fall or winter, well outside nesting season, so no animal is trapped inside and no active nest is disturbed. If you already hear activity in spring, call us to assess before anyone touches it; we will tell you honestly whether it is safe and legal to proceed. Sealing an animal inside is both inhumane and a serious odor and decay problem, so the timing of the work matters as much as the hardware itself.
Before any cap goes on, the flue should be checked and cleaned. A nest left behind is a fire hazard and a draft blocker, and old droppings can carry health risks, so we clear the flue during a chimney sweeping visit and inspect for damage the animals may have caused. We work to the NFPA 211 standard throughout, meaning the mesh openings and clearances on the hardware we install meet the recognized benchmark rather than an installer’s guess.
Homeowners who want this handled once and for all across chimney services in Homer Glen usually book the clean-and-cap together. For straightforward costs before we arrive, see our pricing page.
Frequently asked questions
What is the best way to keep squirrels out of a chimney?
A stainless steel cap with properly gauged spark-arrest mesh, bolted or banded to the crown. Squirrels chew through aluminum, so the metal and the fastening both matter.
Will a chimney cap hurt my draft?
Not if it is sized correctly. The mesh openings must be small enough to exclude animals yet open enough to pass smoke freely. We size the cap to the flue to protect the draft.
Can you remove a bird nest any time of year?
No. Chimney swifts and many songbirds are federally protected, so an active nest with eggs or chicks must stay until the young fledge. We assess first and advise what is legal.
What is a top-sealing damper?
It is a damper that closes the flue at the crown with a rubber gasket when the fireplace is idle, sealing out animals and drafts far better than a worn throat damper down in the firebox.
Do I need to clean the chimney before capping it?
Yes. Any nest, debris, or droppings should be removed first, because leftover material is a fire and draft hazard. We clean and inspect, then install the hardware.
When is the best time to animal-proof my chimney?
Late fall or winter, outside nesting season, so no animal is trapped inside and no protected nest is disturbed. It also gets you ready before the next spring.
Published October 25, 2026.
