How to Replace a Chimney Collar on a Roof

Replacing a leaking chimney collar, sometimes called a storm collar, prevents rainwater from entering the void between the chimney flue and the chimney chase. The flue's bottom connects to the fireplace's firebox. The flue runs through the center of the chimney chase, the brick-and-mortar part of the chimney. The flue's top penetrates the chase top, the metal flashing that covers the top of the chimney chase. The chimney collar slides over the flue and directs water away from the gap between the flue and the chase top. Flue termination caps keep rainwater from entering the flue's interior.

Utility knife
Putty knife
Screwdriver set
High-temperature sealant
Caulking gun

Instructions

- 1
  Cut through the sealant surrounding the joint between the flue pipe's termination cap and the flue pipe with a utility knife. Scrape the sealant from the flue pipe with a putty knife.
- 2
  Loosen the termination cap's mounting screws, using the correct screwdriver to turn the screws counterclockwise. Pull the termination cap off the flue pipe, exposing the chimney collar.
- 3
  Slice the sealant covering the seam between the chimney collar and the flue pipe with the utility knife. Peel the sealant off the chimney collar's mounting band and the flue pipe.
- 4
  Loosen the locking bolt holding the ends of the mounting band together, using the correct-size hex-head screwdriver to turn the bolt counterclockwise.
- 5
  Grip both sides of the chimney collar and lift the collar off the flue pipe. If the flue will not release the collar, slip a slotted screwdriver between the collar and the flue pipe. Pry on the collar with the screwdriver until the collar breaks free of the flue pipe.
- 6
  Slide the new chimney collar over the end of the flue pipe, keeping the wide end of the collar facing down. Position the bottom of the collar against the chase top.
- 7
  Tighten the chimney collar's locking bolt until the collar's band tightens against the flue pipe, using the correct hex-head screwdriver to turn the bolt clockwise.
- 8
  Apply a bead of high-temperature sealant around the seam between the chimney collar and the flue pipe, using a caulking gun to apply the sealant. Cover the collar's locking bolt with the sealant, protecting the bolt's head and threads from moisture-caused damage.
- 9
  Set the termination cap on the end of the flue pipe. Tighten the termination cap's mounting screws with the correct screwdriver.
- 10
  Seal the seam between the termination cap and the flue pipe with the high-temperature sealant.

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