What a chimney camera inspection shows

The limits of a flashlight look

From the firebox, with the damper open and a strong light, you can see the damper, part of the smoke chamber and sometimes the first few feet of the flue. From the top of the chimney, you can see down the top few tiles. Everything in between, which is most of the liner on a typical two-story house, is out of sight.

The Chimney Safety Institute of America (CSIA) points out that flues are allowed to have offsets, so many flues cannot be viewed straight through at all. Even a perfectly straight flue looks like a dark tunnel past the first few feet, and hairline cracks, open joints and small gaps are not visible at that distance.

That middle section is where many problems are: cracked tiles from a past chimney fire, joints that were never filled, and erosion from condensation.

How a camera inspection works

1. Prepare the flueIf heavy soot or creosote would hide the liner surface, the flue is usually swept first.
2. Run the cameraA small, lighted camera on a flexible rod or cable is fed up from the firebox or down from the top. Some cameras can pan and tilt.
3. Watch and recordThe technician watches a live screen, stops at each joint and problem area, and records images or video.
4. Review the findingsThe footage or still images are used to explain what was found and to support recommendations.

CSIA's description of a Level 2 inspection includes visual inspection by video scanning or other means to examine the internal surfaces and joints of all flue liners. Its Level 2 procedure for masonry chimneys lists video scanning for cracks, gaps, liner damage and offsets.

What a camera can show

What a camera cannot show

• Behind the liner. A camera sees the inside face of the flue. It does not show the condition of the brick or framing around it, or clearances to wood, unless there is a gap to look through.
• Through heavy deposits. Thick creosote hides the surface beneath it. Sometimes deposits must be removed before the liner can be judged.
• Around tight bends. Sharp offsets, small flues and some damper and cap configurations can stop a camera or limit its view.
• Inside some factory-built systems. Insulated metal chimneys can be viewed on the inside, but the insulation between the walls is not visible.
• The future. A camera records conditions on that day. It does not show how long a liner will last.

When a camera cannot reach part of the flue, a good report says so. A finding of "could not be viewed" is information too.

When a camera inspection makes sense

• Buying or selling a home with a fireplace or chimney. See Buying a home with a fireplace.
• After a chimney fire or a suspected one. See Signs you've had a chimney fire.
• Before installing an insert, stove, gas logs, or a new furnace, boiler or water heater on an existing flue.
• When smoke, odor or stains show up where they should not.
• After a lightning strike, storm, fallen tree or chimney movement.
• When tile pieces show up in the firebox.
• When a chimney has not been inspected in years.

These line up with the situations CSIA describes as calling for a Level 2 inspection. See Chimney inspection levels 1, 2 and 3.

Reading the results

Camera images can be hard to interpret if you have never seen the inside of a flue. A few tips:

• Ask the technician to point out where in the flue each image was taken, measured from the top or bottom.
• Ask whether a finding is a defect, a maintenance item or normal for the material.
• Keep the photos or video. They give a baseline to compare against next time and can help with insurance or a home sale.
• If the report says part of the flue could not be viewed, ask why and what it would take to see it.

A camera shows conditions. Deciding what they mean for your appliance, and what repair fits, is the next step.

Cameras on different kinds of flues

What a camera can show depends partly on what it is looking at.

• Clay tile liners are the most common in older masonry chimneys. The camera looks at each tile face and each joint between tiles.
• Unlined masonry flues are found in some older homes. The camera shows the condition of the brick and mortar that the smoke touches directly, which can reveal gaps and deterioration.
• Stainless steel liners are checked for deposits, damage, separated sections and corrosion. The insulation around them is not visible.
• Cast-in-place and resurfaced flues are checked for cracks, voids and coating condition.
• Factory-built metal chimneys are checked on the inside for deposits, damage and joint separation; the manufacturer's instructions describe what is acceptable.

Furnace, boiler and water heater flues are often smaller and may have connectors that limit access, but they are frequently worth scanning because condensation can erode them quietly.

Images are evidence, not a verdict

Camera footage is powerful because it shows the actual surface of the flue. It still needs interpretation. A dark line on a tile can be a crack, a creosote streak or a mortar seam. A rough joint may be normal for the age of the chimney or a gap that needs repair. Lighting, lens angle and moisture can all change how something looks.

That is why a camera finding is weighed together with the rest of the inspection: the appliance and fuel the flue serves, the age and type of liner, signs of past fires or leaks, and what the homeowner has noticed. Example images you find online cannot tell you what is happening inside your own chimney. Only an inspection of your flue can do that.

If a recommendation surprises you, ask to see the specific image behind it and have it explained. Clear evidence makes decisions easier, whether the answer is a repair or simply a cleaning and a note to recheck next year.

How we use the camera

Every visit starts with an assessment, and our technicians use a chimney camera when the flue allows. You receive findings with photos before any repair is scheduled, so you can see what we saw. When something needs repair, we explain the options, which may include flue repair or a new liner. See our chimney inspection page, or request service.

Questions homeowners ask

Sources

1. CSIA: Frequently Asked Questions
2. CSIA: The Three Levels of Chimney Inspections
3. CSIA: Level 2 Inspection SOP, Masonry Chimney (PDF)
4. CSIA: After a Chimney Fire

This guide is general information. It can't diagnose a specific chimney; an inspection can.