Chimney anatomy

01 · Chimney cap

A chimney cap sits atop the chimney to prevent rain, debris, and animals from entering.

• Rust or corrosion can weaken the cap.
• Caps can become dislodged or damaged by strong winds.
• Nests or debris can accumulate if the cap is inadequate.

02 · Crown

The crown is a concrete or stone slab that seals the top of the chimney.

• Cracking due to weather exposure can lead to water leaks.
• Poor construction can cause premature degradation.
• Sealant wear may allow moisture to penetrate.

03 · Flashing

Flashing is metal sheeting that creates a waterproof seal between the chimney and roof.

• Improper installation can lead to water leaks.
• Corrosion or rust can cause flashing to fail.
• Sealant can deteriorate over time, allowing water entry.

04 · Brick and mortar

The brick and mortar form the structural walls of the chimney.

• Weathering can cause bricks to crack or spall.
• Mortar joints can erode, leading to structural instability.
• Moisture penetration can lead to further deterioration.

05 · Flue liner

The flue liner guides smoke and gases safely outside, protecting the chimney walls.

• Cracks or gaps can allow gases to escape.
• Build-up of creosote can be a fire hazard.
• Improper sizing can lead to inefficient venting.

06 · Smoke chamber

The smoke chamber funnels smoke from the firebox into the flue.

• Uneven walls can cause smoke to back up.
• Creosote can build up, increasing fire risk.
• Cracks or gaps can disrupt airflow.

07 · Damper

The damper seals the chimney when not in use to prevent drafts and heat loss.

• Rust can make the damper difficult to operate.
• Improper sealing can lead to heat loss.
• Debris can block the damper, preventing closure.

08 · Firebox

The firebox is where the fire is built, and it is lined with firebrick to contain the heat.

• Cracked firebricks can lead to heat damage.
• Mortar joints can degrade, compromising safety.
• Soot and debris can accumulate, requiring cleaning.