How to Read a Chimney Inspection Report

Start with the scope, not the findings

It is tempting to skip straight to the list of problems. The first lines of the report are more important, because they tell you what the findings cover.

• The inspection level. CSIA describes three levels, from a check of readily accessible parts (Level 1) to one that adds a video scan of the flue and accessible attic, basement and crawl space areas (Level 2), to one that involves removing components to reach concealed areas (Level 3). A report that does not name a level is harder to compare later. Our guide to inspection levels explains each.
• The flues and appliances. Count them. A house with a fireplace, a furnace and a water heater may have two or three flues. If the report describes fewer than you have, ask about the missing one.
• Limitations. Roofs too steep or wet to walk, flues blocked by heavy deposits, or areas behind finished walls are normally listed as not inspected. CSIA's own procedure states that following it does not guarantee every defect will be found.

A finding that says nothing was wrong only covers what was actually looked at.

A sample finding, read line by line

"Flue B (gas boiler). Clay tile liner, nominal 8 x 13. Video scan: open mortar joint approx. 14 ft above cleanout; cracked tile approx. 22 ft above cleanout. Liner is oversized for the connected appliance. Recommend a listed liner sized to the appliance before continued use. Priority: safety."

1. Where"Flue B (gas boiler)" tells you which passage and what uses it. Reports often letter or number flues, so keep a note of which is which.
2. What it is"Clay tile liner, nominal 8 x 13" is the material and size. Size matters because liners are matched to the appliance they serve.
3. What was seen, and where along the flueThe heights are measured from a reference point, here the cleanout. They let a second inspector, or a camera on a later visit, find the same spot.
4. What it means"Oversized for the connected appliance" is an interpretation, not just an observation. It is fair to ask what it is based on.
5. What is recommended, and how urgently"Before continued use" and "priority: safety" mean the appliance should not keep venting into that flue until the work is done.

Real reports use their own layouts, but most findings can be pulled apart into these same five pieces. If one is missing, that is the question to ask.

Terms that come up again and again

The code figures above come from the 2003 International Residential Code text reproduced by Buckley Rumford Fireplaces. New Jersey enforces a later edition, and the local construction office applies whatever version is current.

Reading camera stills and photos

Photos are the evidence behind each finding, and the flue photos are the hardest to read. A few habits help:

• Match each photo to a finding. A good report labels photos with the flue and the height or location. If a photo has no caption, ask what it shows.
• Find the joints first. In a clay tile flue, the joints between tiles appear as lines crossing the flue at regular intervals. Once you can see them, a dark gap at a joint or a crack running across a tile is easier to pick out.
• Read the surface. Dull, dry, powdery deposits look different on camera from shiny, glassy ones. Shine usually means a hard deposit that the report should comment on.
• Look for daylight. On a camera still taken near the top, light coming through a wall of the flue is a defect, not a reflection.

A camera shows the inside face of the liner. It cannot see behind it, and heavy deposits can hide the surface. Our guide to camera inspections covers what the video can and cannot reveal.

Putting the findings in order

The report lists findings by location. You have to decide the order in which to act on them, and some depend on others.

1. Anything marked as a safety itemItems that say not to use a fireplace or appliance until corrected come first. Follow that instruction in the meantime.
2. Cleaning, if it was recommendedHeavy deposits can hide damage. A flue swept before the next camera run shows more.
3. Water sourcesCrown, cap, flashing and cricket repairs come before masonry repairs below them. The National Park Service's repointing guidance says the cause of deterioration should be dealt with before repointing.
4. Decisions that set the size of later workIf you are thinking about an insert, a stove or a new furnace, decide before a liner is sized, because the liner is matched to the appliance. See inspection before a new appliance.
5. Masonry and cosmetic repairsRepointing, brick replacement and stain cleanup come once the water is under control.
6. Things to monitorItems marked for observation go on next year's list, with the photo as a baseline.

Timing outside the chimney matters too. If a roof replacement is coming, flashing and crown work are often best planned with it; see planning the chimney with a roof replacement.

When the report says "further evaluation"

Some findings end with a referral instead of a fix. These are not dodges; they mark where a chimney inspection reaches its limits.

• Further evaluation of a concealed area. When a hazard is suspected behind a wall, ceiling or chimney component, CSIA's Level 3 is the step that involves removing parts to reach it. Ask what would be opened and who restores it.
• Evaluation by an engineer. The Brick Industry Association lists cracks wider than about 2 mm, cracks through several bricks and stepped or diagonal cracking among conditions that warrant a professional engineer. A chimney report may refer these out.
• Service by an appliance technician. A chimney inspection looks at how an appliance connects and vents. The burner, controls and gas piping belong to a qualified heating or gas technician.

Comparing two reports or two proposals

If you get a second opinion, the wording will differ even when the findings agree. Compare by part and location rather than by vocabulary:

• Did both inspect the same flues, at the same level, with the same access to the roof and attic?
• Do the measurements and heights roughly match?
• Do both reports show photos of the same condition?
• Where they disagree, is one describing something the other could not reach?

A difference in recommended repairs is often a difference in approach to the same finding, such as relining versus resurfacing a flue. Our guide to flue resurfacing vs. a new liner explains one common example.

Keeping the report useful later

File each report with its date and photos. NFPA 211, as CSIA's FAQ summarizes it, expects a yearly inspection, and each new report is easier to read next to the last one: a crack that has not changed in three years tells a different story from one that appeared since spring. Reports also matter at a home sale and, sometimes, with an insurance claim; see chimney damage and homeowner's insurance.

Our inspections deliver findings with photos before any repair is scheduled, and home-sale inspection reports are handed over on site at the end of the visit. See chimney inspection.

Questions homeowners ask

Sources

1. CSIA: The three levels of chimney inspections
2. CSIA: Level 2 inspection procedure for masonry chimneys (PDF)
3. CSIA: Frequently Asked Questions
4. 2003 International Residential Code, Chapter 10, Chimneys and Fireplaces (text reproduced by Buckley Rumford Fireplaces)
5. Brick Industry Association, Technical Note 46: Maintenance of Brick Masonry (PDF)
6. National Park Service, Preservation Brief 2: Repointing Mortar Joints in Historic Masonry Buildings (PDF)

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