How to Inspect Your Chimney

Chimneys look solid and permanent, but they take a beating. Heat, moisture, freeze-thaw cycles, and corrosive combustion byproducts all work to break them down over time. Meanwhile, inside the flue, creosote accumulates with every fire. Left unchecked, you’re looking at chimney fires, carbon monoxide intrusion, or structural failure. Annual inspection isn’t optional—it’s essential.

Why This Matters

Chimney problems are dangerous because they’re hidden:

• Chimney fires – Creosote ignites and burns at extreme temperatures
• Carbon monoxide – Blocked flues send CO into your home
• Structural collapse – Deteriorated masonry falls
• Water damage – Failed flashing and crowns let water into the house
• Fire spread – Cracked flues let heat reach combustible materials

The consequences of neglect range from expensive repairs to loss of life. Inspection catches problems while they’re still manageable.

What Can Go Wrong

Creosote Buildup

Every wood fire produces creosote—unburned particles that condense inside the flue. It accumulates in stages:

1. First degree: Light soot, brushes out easily
2. Second degree: Flaky, tar-like deposits
3. Third degree: Glazed, shiny, extremely flammable

Creosote is highly combustible. A spark can ignite it, creating a chimney fire that reaches 2,000°F.

Masonry Deterioration

Brick and mortar don’t last forever:

• Mortar joints crack and crumble
• Bricks spall (faces pop off)
• Crown (top surface) cracks
• Water infiltrates and freezes, accelerating damage

Flue Liner Problems

The clay tile or metal liner protects the masonry from heat and gases:

• Cracked tiles
• Missing sections
• Corrosion (metal liners)
• Improper installation

Flashing Failure

Where chimney meets roof, metal flashing creates a watertight seal:

• Rust
• Separation from chimney or roof
• Damaged sealant

Blockages

Anything that restricts airflow is dangerous:

• Animal nests
• Debris
• Collapsed liner sections
• Creosote buildup

Exterior Inspection (DIY)

Walk around your house and look at the chimney from the ground using binoculars:

Crown Condition

The concrete or mortar cap at the top:

• Cracks or missing sections
• Deteriorated surface
• Proper slope (should shed water away from flue)

Cap and Spark Arrestor

If present, check:

• Secure attachment
• No holes or gaps
• Screen intact (keeps animals out)

Masonry

Look for:

• Missing or loose bricks
• Cracked or deteriorating mortar joints
• White staining (efflorescence—sign of water penetration)
• Spalling (brick faces popping off)
• Leaning or tilting

Flashing

Where chimney meets roof:

• Visible gaps
• Rust
• Lifted sections
• Staining on chimney or roof nearby

Overall

• Vegetation growing on chimney (indicates moisture)
• Staining below the roofline (water intrusion)
• Any visible damage

Interior Inspection (DIY)

From the Firebox

1. Open the damper fully
2. Shine a flashlight up the flue
3. Use a mirror to see areas you can’t directly view

Look for:

• Creosote buildup: Black, tar-like deposits on flue walls
• Debris: Leaves, twigs, animal nesting materials
• Damper condition: Operates smoothly, seals when closed
• Visible cracks: In the firebox or smoke chamber
• Smoke stains: On the front of the fireplace (indicates drafting problems)

From the Cleanout

If you have a cleanout door at the base of the chimney:

1. Open it carefully—debris may fall out
2. Look up into the flue
3. Check for debris accumulation
4. Note any creosote presence

Professional Inspection

DIY inspection can catch obvious problems. But certified chimney sweeps see things you can’t:

• Video inspection: Cameras show the entire flue interior
• Hidden damage: Cracks, gaps, and deterioration inside the chimney
• Proper assessment: Level of creosote and cleaning needed
• Code compliance: Whether the system meets current standards

Professional inspections are classified by levels:

• Level 1: Basic visual inspection (annual if no changes)
• Level 2: Includes video scan (when changes made, or after problems)
• Level 3: Involves removal of components for hidden access

When to Call a Pro

Schedule professional inspection:

• Annually if you use the fireplace
• Before the first fire of the season
• After any chimney fire (even small ones)
• If you notice any warning signs
• When buying or selling a home
• After seismic activity or major storms

DIY vs. Call a Pro

DIY: Ground-level exterior inspection, basic firebox check, annual monitoring.

Call a pro: Professional inspection, chimney cleaning, repairs, relining, or any work beyond observation. Find a chimney sweep →

How Often to Inspect

• DIY visual check: Annually
• Professional inspection: Annually if you use the fireplace
• Professional cleaning: As recommended by inspection (usually annually for regular use)

The Bottom Line

Chimneys fail silently until they don’t. A yearly inspection—both your visual check and a professional evaluation—catches problems while they’re fixable. Creosote removal, mortar repair, and flashing fixes are all far cheaper than rebuilding a chimney or recovering from a chimney fire. Don’t skip it.