Squirrel in the Chimney: What to Do

Trapped or nesting?

Squirrels are active in daylight, so the noise comes in the morning and late afternoon rather than at night. The kind of noise tells you a lot about what is going on and how urgent it is. Listen at the fireplace opening and, if the chimney also serves a boiler or water heater, at the cleanout door in the basement.

• Frantic scratching and scrambling, sometimes against the damper: a squirrel that fell in and is trying to climb out
• Scratching that gets weaker over a day or two, then stops: a trapped squirrel running out of strength
• Leaves, twigs and shredded material falling onto the hearth: nest building
• High-pitched chirping or squeaking from one spot: young in a nest
• Thumps and rolling on the roof near the chimney: squirrels using it as a highway

Why squirrels end up inside

Squirrels explore anything that looks like a hollow tree, and an uncapped flue in a mature neighborhood is exactly that. Some climb in deliberately to nest on the smoke shelf or in the top of a large old flue, where the brick is rough enough to grip. Others lean too far over the edge of a smooth clay flue tile and fall.

Late winter to spring and again in late summer are the nesting seasons, and those are when calls about squirrels in chimneys peak. Leafy streets in Queens, Long Island, Westchester, north Jersey and the Philadelphia suburbs see it every year, often on chimneys whose caps rusted away or blew off in a storm.

A squirrel stuck in the chimney

Clay flue tile and metal liners are too smooth to climb. A squirrel that drops into a fireplace flue usually lands on the damper or the smoke shelf behind it. In a heating flue, it can fall all the way to the base and end up behind the cleanout door in the basement, or even inside the connector pipe to the boiler.

If the squirrel is already in the firebox behind closed glass doors, you can open a window or an outside door in that room, close the doors to the rest of the house, then open the fireplace doors and leave the room quietly. Most squirrels run for daylight. Do not open the damper or the cleanout door to look: a frightened squirrel will come straight out at you and into the house.

When the squirrel is in a boiler or water heater flue

A squirrel or nest in a flue that vents a boiler or water heater is more than a nuisance. Nest material can block the exhaust path and push combustion gases back into the basement, and a squirrel trapped at the base can block the connector. If you suspect an animal in a heating flue, keep carbon monoxide alarms working, and treat an alarm, or anyone feeling ill, as a reason to leave and call 911 or the utility.

Do not run the appliance with a known blockage. Call your heating service or the chimney crew to clear the flue before the boiler fires again.

What not to do

Lighting a fire or a smoke bomb can kill young in a nest and set dry nest material burning on the smoke shelf. Mothballs and ammonia rags put fumes into the house and do not reliably drive squirrels out. Poison is a bad idea in a chimney: the animal dies inside and leaves you with the smell, and other animals can be poisoned too.

Climbing on the roof to drop a rope or board down the flue is not worth the risk either. Chimney tops are high, steep and often loose, and the job is easy for someone with the right gear and dangerous for anyone without it.

Who to call

For a live squirrel that will not come out, or a nest with young, call a wildlife removal professional. They can give a trapped squirrel a way to climb out, or use a one-way door at the top so a mother can leave and not return. Mothers have to take the young with them, so timing matters. Some states require a license for paid wildlife removal, so ask.

Call animal control if the squirrel gets into the living space. A chimney crew handles the next part: removing the nest, sweeping the flue, fixing a chewed damper or seal, and capping the top.

• Squirrel in the firebox behind glass: often you can handle it by opening an outside door, then the glass, and leaving the room
• Squirrel trapped on the damper or at the base: a wildlife professional or the chimney crew gives it a way out or removes it
• Nest with young: a wildlife professional lets the mother move them, often with a one-way exit
• After the animals are out: the chimney crew removes the nest, sweeps, repairs and caps the flue

Cleanup and damage checks

Once the chimney is empty, the nest material comes out. Squirrels pack leaves, twigs, insulation and paper onto the smoke shelf, and it is dry, flammable and right where the fire's heat collects. The flue is swept, and the damper is checked for chewed gaskets or bent plates. In heating flues, the base and connector are cleared and the cleanout door checked for a tight seal.

Look for collateral damage too. Squirrels chew on flashing edges, soft caps and the wood trim around a chimney chase, and those gaps can let them into the attic even after the flue is capped.

Squirrel-proofing the top

Squirrels chew. Thin aluminum caps and light screens do not last against them. A heavy stainless steel cap with solid mesh, fastened to the chimney so it cannot be pried up, closes the flue for good. Every flue on the chimney needs one, including the boiler flue, or a single full-width cap can cover them all.

Trim branches that let squirrels jump onto the roof near the chimney. Check for gaps at the flashing and around a framed chimney chase as well, since squirrels can get into the attic that way even when the flue is capped.

After a storm, take a look at the chimney top from the street. Wind and falling branches loosen caps more often than people expect, and a cap knocked sideways in November is often a nest by March. Catching it early means a quick refit instead of another removal and cleanup.