A chimney is a hollow tower with a door to your living room. Without a cap, animals treat it as a front door.

What animals do

Raccoons raise young in flues. Squirrels, birds and bats nest or get trapped. Animals that die inside cause odor and can block the flue.

What a cap does

A stainless steel cap with a screen keeps animals out, blocks rain and stops sparks from reaching your roof.

Choosing a cap

It should fit the flue, have mesh small enough to stop animals and be made of stainless steel or similar material. Have it checked yearly.